PETROLEUM HYDROCARBONS POLLUTION OF NIGERIAN WATERS AND SEDIMENTS AROUND LAGOS AND NIGER DELTA AREA OF NIGERIA By OLADIIPO EBENEZER ADEKANMBi B.Sc. Hons. (Chem) (Ibadan) M.Sc. (Anal. Chem) ( Ibadan) A Thesis in the Department of Chemistry Submitted to the Faculty of Science in Partly Fulfilment of the Requirements for the degree of DiOCTOR OF PHILOSOPHY UNIVERSITY OF IBADAN MARCH 1989 UNIVERSITY OF IBADAN LIBRARY . r • * ' >. ii \-fci - ■, ABSTRACT There i<^a paucity of scientific data on the levels and pattern of distribution of petroleum hydrocarbons in the Nigerian aquatic environment. The levels of total hydrocarbons in 241 water and 222 sediment samples in’ the major river systems draining into Nigerian coastal environment around Lagos and the Niger Delta area have been used to monitor the pattern of distribution of hydrocarbons within these areas over different weather regimes during-1984-85. The Utorogu pipeline oil spillage incident in Bendel State of Nigeria in 1984 was used as a case study for assessment of environmental impact of oil spillage in V - aquatic ecosystem in Nigeria. Samples were also collected and analyzed for total hydrocarbons from Kaduna (Northern Nigeria) and Ibadan (Western Nigeria) for comparative information and controls respectively. Water samples were analyzed for .petroleum'hydro - carbon by infrared (IR) and gas chromatographic (GC) techniques whereas sediment samples were analyzed by gravimetry and gas chromatography (GC). i UNIVERSITY OF IBADAN LIBRARY t iii The infrared (IR) results for 1984 (wet season) showed that Lagos and Lekki lagoons had hydrocarbon level (presented as range followed by mean value in bracket), 1.64-11,40 (S.60) mg/1; Niger Delta, ND (net detectable)-70.70 (6.1S)mg/l; Utorogu 0.17-10.50 (2.22)mg/l; Kaduna 4.30-9.90-(6.98)mg/1, while Ibadan water samples (serving as control area)' showed no detectable levels of hydrocarbon. In 1985 (dry season) there was a decrease in the \ - ■ hydrocarbon levels found in the water samples. Lagos and Lekki lagoons recorded 0.10-0.41 (0.25)mg/l; Niger Delta 0.10-1.80(0.52)mg/l and Utorogu 0.1_-4.67 (2.14)mg/1. The gas chromatographic values for hydrocarbon ' * concentration in water were much lower than the infrared values. All the samples except Upomani discharge point (3.36 mg/1) had values below 1 mg/1 by GC. Nonetheless, the 1R values correlated well with the GC values. . ‘ The corresponding hydrocarbon levels (on dry weight basis) in i sediment samples in 1984■ were: . Lagos and Lekki lagoons ND-95.54 (30.33) pg/g;' UNIVERSITY OF IBADAN LIBRARY IV Niger Delta ND-74.05 (9.09) pg/g; Utorogu 14.04- 267.48 (98.88) pg/g and Kaduna 0.62-21.52 (12.36) pg/g* ' In 1985 the values of hydrocarbon levels recorded in the sediment samples were as follows: Lagos and ‘ Lekki lagoons 0.20-10.30 (4.20) ug/g; » Niger Delta 0.05-44.06 C6.64) pg/g; Utorogu (Jan- Feh.) ND-9.41 (2.98)pg/g; Utorogu (June-July) 0.03- 68.06 (21.66)pg/g; Kaduna 2.91-5.00 (5.96)pg/g and Ibadan 8.09-27.79 (17.94)ug/g. The Lagos lagoon sedi­ ment samples monitored from January to December 1985 gave ND-2766. 27 -fll.13)pg/g. , * v The results of this work showed that Lagos lagoon was more polluted than the Niger Delta in terms of petroleum hydrocarbons. Highest values of petroleum hydrocarbons were recorded close to oil activity points such as Ogharife field effluent canal, Chanomi- creek at Egwa field, Orughene creek, in the Niger Delta arxe a; or near human settlements s.uch as Obotebe andi Bakana or in an industrial area.like Lever Brother's discharge point and Berger/National Oil/Ijora in Lagos. UNIVERSITY OF IBADAN LIBRARY i V The results of Utorogu oil spillage gave a pic­ ture of the impact of oil in the aquatic environment. During the first sampling trip which took place within four months after the oil incident, aquatic t* ' lives (plants and animals) were seriously affected in the Utorogu swamp, but before the end of the study * period (June 198S) the swamp had recovered and was bubbling with life again. Oil pollution indicator parameters such as the Carbon Preference Index (CPI), Pristane:Phytane ratio (Pr/Ph); Presence of Phytane, and Unresolved Complex Mixture QJCM) and the. Marine Oil Pollution Index (MOPI) indicated that some of the stations were polluted by oil while most of the points studied in both Lagos and the Niger Delta were contaminated with petroleum hydrocarbons which may be from crude oil, refined oil or both. Moreover, all the contaminated and polluted samples showed petroleum hydrocarbon at different stages of weathering as reflected in their carbon i range, the Pristane: n-C^yj Phytane:n-C^g and UCM: n-alkane ratios. UNIVERSITY OF IBADAN LIBRARY ACKNOWLEDGEMENTS My sincere thanks go to my supervisor, Dr. 0. Osibanjb, for his guidance, criticisms, suggestions, encouragement and supervision to make this work a success. He was a constant inspiration to 'me throughout the programme and I also learnt some useful lessons from him. ------______ ' • I am also very grateful to Professor J.- A. Faniran for his care and love to see me through this programme, Dr, S. 0. \Ajayi, Dr. B r-B. Adeleke, Dr. R. Oderinde and Dr. C. M. Ekweozor for their invaluable contributions towards the successful outcome of this wo.rk. I will like to seize this opportunity to thank Dr. J. Nwankwo of the NNPC, Mr. Courant and all the personnel of the Research Planning - Institute (RPI) of South Carolina, u.S.A. and Mr. Ajao of the Nigerian •Institute for Oceanography and Marine Research (NIOMR), for the collection of samples and all other necessary information needed for this project. The Environmental Protection Service of Canada for the useful literature materials. UNIVERSITY OF IBA AN LIBRARY Vll My sincere thanks also go to my brother, Mr. Yomi Adekanmbi, for his personal sacrifice and the willingness with which he took over the great burden left behind by our late father, -Pa Peter Aroh Adekanmi. He is the embodiment of kindness and a good motivator. Furthermore, my special thanks go to the following persons for their encouragement and support - Messrs Segun, Kehinde, Taiwo and Dotun (baby of the home) Adekanmbi. My thanks also go to the Head of lEhvironmental Science Department, Ibadan Polytechnic and the laboratory staff of the same department, Chemistry Department, University of Jos, Chemistry Department, Obafemi Awolowo University and Mr. Aiyemonisan of the Chemistry Department, Obafemi Awolowo UniversityH. Some lovely friends also deserve special thanks for their various contributions. These include my one and only Alhaji Kolade Jinadu. He is a special brand of friend who gave me everything humanly possible and always put a smile on my face. Dr. Kayode Bamgbose UNIVERSITY OF IBADAN LIBRARY v m (Coachito), he is also in a special class. My asso­ ciation with him was very rewarding and his recruitment skill defiend any scientific explanation. Mr. Frank Aigbokhan lent me a big hand when it mattered most. Messrs Adeyeye and Ajewole were always at hand with their words of wisdom. I shall not fail torrecognise the special love and care given to me by my dearest mother, Madam Adesipe Adekanmbi and my ever-loving mother-in-law, Madam Lydia Bodunrinde. Other lovely people worthy of mention for their unalloyed support are Mr. and Mrs. Femi Oguntoyinbo, Mrs. Ladun Ogunbuyide, Mrs. Bunmi Adekanmbi, Miss Yemi Bodunrinde, Miss Morenike Bodunrinde, Surv. Seinde Esan, Mr. and Mrs. Awelewa, Dr. and Mrs. Omoleye, Dr. and Dr. (Mrs.) Dairo, Mr. and Mrs, Osegboun, Mr. Kayode Abegunde, Femi Olatunji, Timothy Adedayo, Miss Ima-Qbong Etuknwa and Foluso Oguntoyinbo. I need to say a very big thank you to my kind, loving and devoted wife, Mojisola Alake for standing by me through thick and thin of this programme and for wearing a man's heart even when situation appeared so UNIV RSITY OF IBADAN LIBRARY 5 I • ix • hopeless. I doff my hat in great salute to my Jewel of inestimable value. I also thank my children, Toyin, Tosin, Tope Diipo (Jnr.) and Tomilola for their love, understanding and patience during the course of this work, ' ‘My thanks also go to Mrs. Petters for the marve­ llous job she did in typing the worh and Mr. J. Faborode for the diagrams. • V ' I am also very grateful to the Chemistry Depart­ ment, University of Ibadan for providing most of the facilities used for this research work. Finally, I am very grateful to my Heavenly Father and to Him I give all thanks,.honour and glory for His kindness and mercy over me and my family. UNIVERSITY OF IBADAN LIBRARY t DEDICATION This work is dedicated to the GLORY OF GOD for HE has been so wonderful and gracious to me and my family thrpugh CHRIST JESUS. "Give thanks in all circumstances, for this is God’s will • for you in Christ Jesus." v'*'’ V- ' I Thes. 5:18. UNIVERSITY OF IBADAN LIBRARY i XX CERTIFICATION I certify that this work was carried out by Oladipo Ebenezer ADEKANMBI in the Department of Chemistry, University of Ibadan. DR. 0. OSIBANJO, C.Chem., MRSC, -B.Sc. Hons (lb.), M.Sc., Ph.D. (B'harm); Reader in Analytical Chemistry,’ University of Ibadan, Ibadan, Nigeria. UNIVERSITY OF IBADAN LIBRARY TABLE OF CONTEXTS \ \ Page TITLE i ABSTRACT ii A C KNOWLE D CEMENTS v i DEDICATION x CERTIFICATION x i TABLE OF CONTENTS x ii LIST OF TABLES . :xx iv . LIST OF FIGURES xxx i i i CHAPTER ONE: INTRODUCTION 1 1.1 THE ORIGIN OF PETROLEUM ... 1. 1.1.1 METAMORPHOSIS 5 1.1.2. MIGRATION 9 1.2 THE NATURE OF PETROLEUM ... 12 . 1.2.1 COMPOSITION 12 1.2.1.1 HYDROCARBONS • « n 13 1.2.1.2 POLYNUCLEAR AROMATIC HYDROCARBONS (PAHS) 20 1.2.1.3 NON-HYDROCARBONS ... 28 UNIVERSITY OF IBADAN LIBRARY 1 ! xiii Page l.o DISTINGUISHING FEATURES BETWEEN BioGENIC AND ANTHROPOGENIC HYDROCARBONS ... 35 1.4 CONCEPT OF POLLUTION ... ... 45 1.4.1 MARINE POLLUTION ... 46 1.4.2 THE FATE OF POLLUTANTS ... 48 1.5 SOURCES OF HYDROCARBONS IN THE MARINE ENVIRONMENT ... . . _* . ____ 54 1.5.1 BIOSYNTHESIS ... . ... 55 1.5.2 GEOCHEMICAL PROCESS ' ... 57 1.5.3 ANTHROPOGENIC INPUT .... 60 1.6 AIR POLLUTION FROM THE USE OF PETROLEUM- 68 1.6.1 INTRODUCTION ... ... 68 1.6.2 t EFFECTS ON FLAN ... ... 70. 1.6.3 EFFECTS'ON ANIMALS ... 77. 1.6.4 EFFECTS ON.PLANTS • ... 78 1.6.5 METEOROLOGICAL EFFECTS ... 78. 1.7 THE PHYSICAL, CHEMICAL AND BIOLOGICAL FATE OF OIL IN THE MARINE ENVIRONMENT ... 79 1.7.. 1 EVAPORATION ... . .... 81 1.7.2 DISSOLUTIONS . . ... 83- 1.7.3 MICROBIAL (BIOCHEMICAL) DEGRADATION - ... ... 88 UNIVERSITY OF IBADAN LIBRARY / XIV Page 1.7.4 CHEMICAL DEGRADATION 97 1.7.5 EMULSIFICATION ... 99 1.7.6 FORMATION OF TAR LUMPS 102 1.8 PATHWAYS AND TOXICOLOGICAL EFFECTS OF PETROLEUM POLL»U TION .... • 102 1.8.1 . EFFECTS OF OIL POLLUTION ON LAND ■ 1.03 1.8.2 EFFECTS OF OIL POLLUTION ON ' AQUATIC ORGANISMS . 106 ■ ' 1,9: OIL SPILLS: A GLOBAL PICTURE ... 116 1.10- OIL POLLUTION PROBLEMS IN NIGERIA ... 125 1.11 AIM OF STUDY .... 132 CHAPTER TITO: DETERMINATION OF PETROLEUM HYDROCARBONS IN ENVIRONMENTAL • SAMPLES 135 2.1- INTRODUCTION 135 2.2 SAMPLING, CHOICE OF SAMPLE AND SAMPLE PRESERVATION 140 2.2.1 WATER . ... - 141 2.2.2 SEDIMENT 14? 2.3 SAMPLE COLLECTION AND FREQUENCY OF SAMPLING ... ' 14 3 2..3.1 SAMPLE CONTAINERS 14 5 UNIVERSITY OF IBADAN LIBRARY I XV Page 2.4 SAMPLING AND tSAMPLE PRESERVATION • • • 146 : ;4.i SAMPLING • • • 146 2.4,2 IN-SITU SAMPLING SYSTEMS’FOR WATER • « • 151 2.4.3 PROBLEMS OF SAMPLING FOR WATER 152 2.4.4 SAMPLING FOR SEDIMENT • • • 15 3 2,. 4,5' PRESERVATION * • * 155 2.5 EXTRACTION OF SAMPLES . . . 156 2.5.1 EXTRACTION OF WATER SAMPLES . ; . 157 - 2.5,2 DETERMINATION OF VOLATILE HYDROCARBONS IN- WATER • • • 15 8 2.5,3 COUPLED COLUMN LIQUID CHROMATOGRAPHY ... • • • 160 2.5.4 SOLVENT EXTRACTION OF PARTICULATE MATTER • • • 163 2.5.5 SOLVENT EXTRACTION OF WATER ■ • • 165 2.5. 6 COMMENTS ON THE SOLVENT EXTRACTION OF WATER SAMPLES • • • 17 2 2.5.7 EXTRACTION OF SEDIMENT • • • 174 2.5.8 COMMENTS ON THE SOLVENT ^ EXTRACTION OF SEDIMENT SAMPLES 192 2.6 A RAPID FIELD METHOD FOR DETECTING OIL IN SEDIMENTS ... ;.. 193 UNIVERSI Y OF IB D N LIBRARY 1 XVI Page CLEAR-UP OF SAMPLE EXTRACTS • • * 196 2.7.1 COLUMN CHROMATOGRAPHY (CCJ • * • 197 2.7.2 THIN LAYER CHROMATOGRAPHY (TLC) 199 INSTRUMENTAL ANALYSIS OF PETROLEUM HYDROCARBONS ' • • * 201 2.8.1 GRAVIMETRY • • • 203 2.8.2 SPECTROPHOTOMETRIC METHODS • • % 204 2.8.2.1 INFRARED SPECTROMETRY . . . 205 2.8.2.2 ULTRAVIOLET ABSORPTION SPECTRO­ PHOTOMETRY 209 2,8.2.3 FLUORESCENCE SPECTROMETRY . . . 2 20 2.8.3 HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC) • • • 222 2.8.4 GAS LIQUID CHROMATOGRAPHY (GLC) 226 2.8.4.1 SAMPLE INTRODUCTION * • * • 230 2/8.4.2 THE SUPPORT • * « 231 2.8.4.3 COLUMN TUBING • • « 235 2.8.4.4 UPPER TEMPERATURE LIMIT • • to 237 2;8.4.5 SAMPLE RECOVERY ... • * « 241 2.8.4.6 DETECTOR < * • 242 2.8.4. 7 PACKED GC COLUMNS FOR SEPA RATING HYDROCARBONS" « « • 243 UNIVERSITY OF IBADAN LIBRARY / X V I 1 • - Pa^e 2.8.4.7.1 ADSORBENTS . « • • 245 2.8.4.7.2 MODIFIED ADSORBENT • • • 245 2,8.4.7.3 CONVENTIONAL PACKED COLUMNS • • • 246 2.8.5 COMPARISON OF CAPILLARY' COLUMN AND PACKED COLUMN GC FOR / HYDROCARBONS ANALYSIS 248 / 2,8.5.1- NATURE OF THE COLUMNS ♦ • • 249 2.8.5.1.1 COLUMN MATERIAL • • • 250 2. 8.5.2 SAMPLE CAPACITY ... « • • 251 2.8.5,3 SEPARATION EFFICIENCY AND - RESOLUTION 252 2.8.6 GAS CHROMATOGRAPHY-MASS SPECTROMETRY __ 254 CHAPTER THREE: EXPERIMENTAL ... « • • 258 3.1 DESCRIPTION OF THE SAMPLING AREA • • • 25 8 3.1.1 WATER-TYPE CLASSIFICATION * • • 281 - 3.2 SOLVENTS AND CHEMICALS « • • 285 3. 2.1 PRECAUTIONARY MEASURES • • » 285 3. 2. 2 CHEMICALS . . . . • • * 285 3. 2.3 REFERENCE OIL . . 1 . : . . 286 3.2.4 INTERNAL STANDARDS • • « 287 . 3. 2.4.3. PREPARATION OF INTERNAL STANDARDS * * * 288 UNIVERSI Y OF IBADAN LIBRARY xv ii i \ Page 3.2.4.2 EXTERNAL STANDARDS 288 3.3 APPARATUS AND EQUIPMENT ... 292 3.4 a APPROACHES TO THE PETROLEUM HYDROCARBONS DETERMINATION" - ... 294 3.5 CLEANING OF APPARATUS 'AND REAGENTS 296 3.6 WATER,SAMPLES COLLECTION AND PRESERVATION 297 3. 7 SEDIMENTS * . . . ___ 298 * 3.8 DETERMINATION OF PETROLEUM HYDROCARBONS 299 3. 8,1 RECOVERY STUDIES BY I.R 300 . 3.8.2 PRECISION STUDIES BY IR SPECTROPHOTOMETRIC METHOD 302 3.8.3 CALIBRATION GRAPH FOR OIL IN WATER BY INFRARED SPECTROMETRY 303 3.9 DETERMINATION OF PETROLEUM HYDROCARBONS IN SEDIMENTS 309 3.9.1 INTRODUCTION 309 3.9.2 EXTRACTION TECHNIQUES • ... 310 3.9.2.1 REFLUX METHOD 510 3.9.2.1.1 SAMPLE PREPARATION 310 3.9,2.1.2 DETERMINATION OF DRY WEIGHT OF SEDIMENT SAMPLE ... . . . ' 311 3.9.2.1.3 DIGESTION OF SEDIMENT SAMPLE * * • 312 UNIVERSITY OF IBADAN LIBRARY XIX Page 3.9.2.1.4 EXTRACTION OF PETROLEUM HYDROCARBONS ... ... 312 3.9.2.1.5 CLEANUP OF EXTRACTS USING SILICA GEL COLUMNS ... 313 3.9’. 2.1.6 SEPARATION OF ALKANES AND ' * . . - AROMATICS USING ALUMINA COLUMN 314 3.9.2.2 SOXHLET EXTRACTION METHOD ... 316 3.9.2.2.1 EXTRACTION ... * ... 516 3.9.2.2.2 COLUMN CHROMATOGRAPHY ... 318 \\ . 3.9.3 PRECISION STUDIES ... 320 3.10 QUALITATIVE AND QUANTITATIVE DETERMINA­ TION OF PETROLEUM HYDROCARBONS IN SEDIMENTS— ... ... 320 3.10.1 CALIBRATION ... ... 523 3.10.2 IDENTIFICATION' ... ... 523 3.10.3 QUANTIFICATION .... .... 329" . 3a0.-3.1 PEAKS ... ... 330 3.10.3.2 UNRESOLVED COMPLEX MIXTURE (UCM) 532 CHAPTER FOUR: RESULTS AND DISCUSSION ... 334 4.1"' ANALYTICAL DATA QUALITY ASSURANCE ... 334 4.1.1 THE RECOVERY STUDY OF OIL IN WATER ... ... 334 / . v UNIVER ITY OF IBADAN LIBRARY t XX Pa ' > l 4,1.2 THE RECOVERY STUDIES OF PETROLEUM HYDROCARBONS IN SEDIMENTS/ * * * 33S 4.1.3 STATISTICAL ANALYSIS • • • 54 5 CONFIRMATION OF THE HYDROCARBON COMPOUNDS 346 RESULTS • • * * • « • 352 4.3.1 SURFACE. WATER RESULTS i • t 35 2 4.3.1.1 LAGOS AND LEKKI LAGOONS % • • 35 3 4.3,1. 2 BENIN RIVER SYSTEM • • * 354 4.3.1.3 ESCRAVOS RIVER SYSTEM , « • « 355 4.3.1.4 FORCADOS-WARRI RIVER SYSTEM * • • 356 4.3.1.5 RAMOS RIVER SYSTEM • • •. 356 4.3.1.6 ’NUN-EKOLE-BRASS ... • • • 357 4.3.1.7 ORASHI RIVER SYSTEM • * • 357 4.3.1.8 BONNY-NEW CALABAR RIVER SYSTEM 358 4.3.1.9 IMO RIVER SYSTEM • • • 358 4.3.1.10 CROSS RIVER-CALABAR RIVER SYSTEM • • • 359 4.3.1.11 KADUNA RIVER SYSTEM • • * 359 4.3.1.12 IBADAN « • • 359 4.3.1.13 UTOROGU SWAMP AND OKPARI RIVER 571 UNIVERSITY OF IBADAN LIBRARY XXI Pa qe 4.4 DISCUSSION ... ... 574 4.5 SEDIMENT ... ... 583 4.5.1 LAGOS AND LEKKI LAGOONS 384 4.5.2 BENIN RIVER SYSTEM ...' 385 4.5.3 ESCRAVOS RLVER SYSTEM ... 586 4.5.4 FORCADOS-WARRI RIVER SYSTEM ... 5S6 4.5.5 RAMOS RIVER SYSTEM • '... 5S7 4.5.6 NUN-EKOLE-BRASS RIVER SYSTEM ... 5S7 4.5.7 ORASHI RIVER SYSTEM .. . 587 4.5.8 BONNY-NEW CALABAR RIVER SYSTEM ' 588 4.5.9 IMO RIVER SYSTEM -... 588 4.5.10 CROSS RIVER-CALABAR RIVER SYSTEM 589 4.5.11 KADUNA RIVER SYSTEM ... 589 -4.6,1 LAGOS AND LEKKI LAGOONS ... 397 4.6.2 BENIN RIVER SYSTEM ' ... 397 4.6.3 • ESCRAVOS RIVER SYSTEM ... 598 4.6.4 FORCADOS-WARRI RIVER SYSTEM ... 598 4.6.5 ORASHI RIVER SYSTEM ... 399 4.6.6 BONNY-NEW CALABAR RIVER SYSTEM 599 4.6.7 CROSS RIVER-CALABAR RIVER SYSTEM 599 UNIVERSITY OF IBADAN LIBRARY XXII Pa e*e 4.6.8 KADUNA 404 4.6.9 IBADAN 404 4.6.10 UT0R0GU SWAMP AND OKPARI RIVER 4.6.11 LAGOS LAGOON (JAN-DEC. 19S5) .. i.~ GAS CHROMATOGRAPHIC DATA ... 417 4.7.1 LAGOS AND LEKKI LAGOONS 4Tr1X £O 4. 7. 2 NIGER DELTA ... * s. 426 4.7.3 UTOROGU SWAMP AND OKPARI RIVER 4 30 l.S DISCUSSION - ... 4 40 4..8.1 LAGOS AND LEKKI LAGOONS • I 7TP "Tr £m 4.8.2 BENIN RIVER SYSTEM 4 43 4.8.3 ESCRAVOS RIVER SYSTEM 4.8.4 FORCADOS-WARRI RIVER SYSTEM 4.8.5 RAMOS RIVER SYSTEM * 446 4.8.6 NUN-EKOLE-BRASS RIVER SYSTEM 447 4.8.7 ORASHI RIVER SYSTEM 4.8.8 BONNY-NEW CALABAR RIVER SYSTEM 448 -^4.8.9 IMO RIVER SYSTEM ... 448 4.8.10 CROSS RIVER-CALABAR RIVER SYSTEM 449 4.8.11 KADUNA RIVER-SYSTEM 449 UNIVERSITY OF IBADAN LIBRARY • xxiii Pa qe Pace 4.5.12 IBADAN ... • ... 45S 4.8.13 UTOROGU-OKPARI SYSTEM ... 45S 4.8.14 LAGOS LAGOON CJAN-DEC. 19S5) ... 465 -.1 OVERALL SUMMARY OF SEDIMENT RESULTS CIS 84-19 85) ... ... 467 PETROLEUM HYDROCARBON CONCENTRATION MAPS 476 -.11 HYDROCARBONS SOURCE CHARACTERIZATION ... 477 -.11 WEATHERING OF PETROLEUM IN THE AQUATIC ENVIRONMENT IN THE STUDY AREAS ... 525 -15 ACCUMULATION OF PETROLEUM HYDROCARBONS 541 -.1- COMPARISON OF LEVELS OF PETROLEUM HYDROCARBONS IN SEDIMENTS OF NIGERIAN- COASTAL WATERS WITH SIMILAR RESULTS FROM OTHER COUNTRIES ... ... 546 -.15 CONCLUSION ! ... ' ... 551 -.16 SUGGESTIONS FOR FUTURE STUDY ... 555 - 17EAENCES ... ... 557 UNIVERSITY OF IBADAN LIBRARY ( xxiv ' LIST OF TABLES Table THE AVERAGE" COMPOSITION OF CRUDE OIL ... ... 15 2 'HYDROCARBON COMPOUND TYPES * . . - 19 5 SOME POLYNUCLEAR AROMATIC HYDROCARBONS FOUND IN THE MARINE ENVIRONMENT •. . . . 22 4 . ELEMENTAL ANALYSIS OF CRUDE OILS ‘ ... 54 5A ORGANIC POLLUTANTS OF NATURAL ORIGIN PARTLY CHANGED BY PROCESSING -(TENTATIVE) ... ... 51 SB • ORGANIC POLLUTANTS OF SYNTHETIC ORIGIN . (TENTATIVE) .... ... 52 6 ESTIMATED ANNUAL INPUTS OF OIL TO. THE OCEANS, 1978 ... ... 66 7 INDUSTRIAL SOURCES OF AIR POLLUTANT EMISSIONS .... ... 69- 8 SOLUBILITIES OF ALIPHATIC AND AROMATIC PETROLEUM HYDROCARBONS IN SEAWATER AND DISTILLED WATER AT 25°C ... 87 9 •... MICRO-ORGANISMS CAPABLE OF OXIDIZING/ CO.-OXIDIZING PETROLEUM HYDROCARBONS AND/OR THEIR DERIVATIVES ... 95 TCf" EVALUATION OF EXPERIMENTS AND OBSERVA­ TIONS OF THE SUBLETHAL EFFECTS ON ORGANISMS BOTH OF POLLUTION AND OF OTHER ASSOCIATED ACTIVITIES OF THE PETROLEUM INDUSTRY 115 UNIVERSITY OF IBADAN LIBRARY XXV 'zble ?age ' : MAJOR OIL SPILLS (1957-1983) 117 OIL SPILL INCIDENTS IN WEST AND CENTRAL AFRICA, 1975-1980 INVOLVI! - SHIPPING ... 12 2 15 • THE MAJOR OIL SPILLS IN NIGERIA 1978/79 129 - f AN OVERVIEW OF OIL SPILLAGE IN- NIGERIA, 19 72-79 ... ' . . . 1 SO 15 YEARLY DISTRIBUTION OF OIL SPILLS. 1970-1982 . . . 131 16 .RELATIVE CONCENTRATIONS OF OIL IN- FILTERABLE ,■FILTER-PASSING AND UNFILTERED SAMPLES /BY FLUORESCENCE SPECTROMETRY), pg/100 ml 1 ~]f\ 17 ANALYTICAL TECHNIQUES FOR THE DETERUMINATION OF HYDROCARBONS IN- WATER 171 18 COMPARISON OF METHYLENE CHLORIDE (CH-jQ - " AND' TETRACHLOROMETHANE CCC1 0 AS ~ SOLVENTS FOR EXTRACTING PETROLEUM RESIDUES FROM SEA WATER COLLECTED ALONG THE HALIFAX-BERMUDA SECTION USING T-TEST FOR PAIRED VARIABLES - THE DIFFERENCE WAS SIGNIFICANT AT THE 951 LEVEL . ... i #3 19 . ANALYTICAL TECHNIQUES FOR THE DETERMINATION OF HYDROCARBONS IN- SEDIMENT 178 20 COMPARISON OF EXTRACTION METHODS FOR HYDROCARBONS IN MARINE SEDIMENTS ... ISO UNIVERSITY OF IBADAN LIBRARY XX Y1 Tabl e Page 21 PER CENT RECOVERY OF HYDROCARBONS ADDED TO SEDIMENT 184 22 ■ METHODS OF SEDIMENT ANALYSIS IN * INTERLABORATORY CALIBRATION 186 23 SUMMARY OF INTERLABORATORY INTER­ CALIBRATION EXERCISE-S 1976-81 ... 189 24 • CONCENTRATIONS (IN PPM) OF ' NAPHTHALENE (N), ME THYL NA PHTHAL EXES (MN) IN WATER SOLUBLE FRACTIONS OF 3 OILS AS DETERMINED BY GAS CHROMA- TOG RAP HY (GC) AND ULTRAVIOLET SPECTROPHOTOMETRY (UV) - ... 216 25- ULTRAVIOLET ABSORBANCE CHARACTERIS­ TICS OF THE OIL AT DIFFERENT CONCENTRATIONS FROM POLLUTED VICTORIA BAY • ... ... 218 26 ULTRAVIOLET ABSORBANCE CHARACTERISTICS OF A CRUDE OIL AT DIFFERENT CONCENTRATIONS ... ... 219 27 SUMMARY OF ANALYTICAL METHOD (GC) FOR PETROLEUM HYDROCARBONS IN ENVIRONMENTAL SAMPLES _ ... 238 28 GAS CHROMATOGRAPHIC DETECTORS AND THEIR APPLICATION ... ... 244 29 COMPARISON OF PACKED AND CAPILLARY ^ COLUMNS AND METHODS .... ... 256 30 DESCRIPTION OF SAMPLING STATIONS FOR WATER AND SEDIMENTS AROUND LAGOS AND NIGER DELTA AREAS OF NIGERIA 1984-85 265 UNIVERSITY OF IBADAN LIBRARY xxv ii 'able Page 31 ' DESCRIPTION OF SAMPLING STATIONS ON 0KPAR1 RIVER 276 32 LAGOS LAGOON STATIONS 278 35 COMPOSITION OF MIXED ALIPHATIC HYDRO­ CARBON STANDARDS FOR GC ANALYSIS ... 290 34 COMPOSITION OF MIXED AROMATIC HYDRO­ CARBON STANDARDS FOR GC ANALYSIS. ... 291 35 CONCENTRATIONS AND ABSORBANCE DATA OF SYNTHETIC STANDARD FOR THE CALIBRATION GRAPH OF OIL IN WATER -BY INFRARED SPECTROPHOTOMETRIC METHOD 306 36 . THE ELUTION OF THE DIFFERENT FRAC-- TIONS IN THE SEPARATION OF ALKANES AND AROMATICS FROM A SEDIMENT EXTRACT 315 37 PACKED COLUMN GAS CHROMATOGRAPHY/ FLAME IONIZATION DETECTION ANALYTICAL CONDITIONS USED.'' IN THE PRESENT STUDY 322 38 RECOVERY DATA OF OIL IN WATER BY INFRARED SPECTROPHOTOMETRIC METHOD . 336 39 PRECISION DATA OF OIL IN WATER BY TETRACHLOROMETHANE EXTRACTION WITH INFRARED.SPECTROPHOTOMETRIC METHOD 337 40 PERCENTAGE RECOVERY OF ALKANES FROM SPIKED SEDIMENT SAMPLES BY- TWO • DIFFERENT EXTRACTION METHODS 339 41 PERCENTAGE RECOVERY OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) FROM • SPIKED SEDIMENTS BY TWO DIFFERENT METHODS 340 UNIVERSITY OF IBADAN LIBRARY • xxviii a b l e P a g e 4 2 PRECISION DATA OF HYDROCARBONS IX SEDIMENTS BY REFLUX AND SOXHLET EXTRACTION METHODS ... ... 342 -3 RESULT OF REFERENCE SAMPLE (0039 IAEA/MONACO) EXTRACTED BY BOTH REFLUX AND SOXHLET METHODS ... 347 • ^ .1 TOTAL HYDROCARBON CONCENTRATIONS IN If ATE R SAMPLES FROM LAGOS AND LEKKI LAGOONS BY INFRARED SPECTRO- PH0TOMETRIC (IR) AND GAS. CHROMATO­ GRAPHIC CGC) METHOD (mg/1) f . - 360 -4.2 TOTAL HYDROCARBON CONCENTRATIONS IN WATER SAMPLES FROM BENIN RIVER SYSTEM (mg/1) ... ... 561 --.3 TOTAL HYDROCARBON CONCENTRATIONS IN WATER SAMPLES FROM ESCRAVOS RIVER TOTAL HYDSRYOCSATREBMON' CONCENTRATIONS IN W.A.T.E R SAMPLES FR.O.M. . 362 44.4 FORCADOS RIVER SYSTEM ... 363 44.5 RAMOS RIVER SYSTEM ... * ... 364 44.6 NUN-EKOLE-BRASS RIVER SYSTEM ... 365 44.7 ORASHI RIVER SYSTEM ... ... 366 44.8 BONNY-NEW CALABAR RIVER SYSTEM ... 367. 44.9 IMO RIVER SYSTEM ... ... 363 4 4.10 CROSS RIVER-CALABAR RIVER SYSTEM . . 3 6 9 44.11 KADUXA RIVER SYSTEM ... * "... 370 44.12 IBADAN .... . .. 370 UNIVERSITY OF IBADAN LIBRARY X X I X Table 15 TOTAL HYDROCARBON CONCENTRATION IN WATER SAMPLES AT UTOROGU SWAM? AND OKPARI RIVER IN SENDEE STATE BY INFRARED SPECTROMETRI'C CIR) METHOD a . . . • • • 572 -6 PETROLEUM HYDROCARBON LEVELS BY GC IN SOME WATER SYSTEMS COMPARED WITH NIGERIA WATER SY* STEM ... • 582 47 ' GRAVIMETRIC DATA OF SEDIMENT SAMPLES AROUND LAGOS AND NIGER DELTA AREA OF NIGERIA, WET SEASON (AUGUST-NOVEMBER 1984) (jig g"1 DRY WEIGHT) 390 \ ig GRAVIMETRIC DATA OF SEDIMENT SAMPLES AROUND LAGOS AND NIGER DELTA AREAS OF ■ NIGERIA (FEBRUARY 198.5) (DRV WEIGHT BASIS) 400 ^9 GRAVIMETRIC DATA OF SEDIMENT SAMPLES AT UTOROGU SWAMP AND OKPARI RIVER IN BENDEL STATE OF NIGERIA (OCTOBER 1984) 406 . 50 GRAVIMETRIC DATA OF SEDIMENT SAMPLES AT UTOROGU SWAMP AND OKPARI RIVER IN BENDEL STATE OF NIGERIA (JAN-FEB. 1985) 408 51 GRAVIMETRIC DATA OF SEDIMENT SAMPLES AT UTOROGU SWAMP AND OKPARI RIVER IN BENDEL STATE OF NIGERIA (JUNE- JULY 1985) 410 SI'' GRAVIMETRIC DATA OF SEDIMENT SAMPLES FROM LAGOS LAGOON (FEBRUARY-DECEMBER 1985) (DRY WEIGHT BASIS) 413 UNIVERSITY OF IBADA LIBRARY XXX Page 53 THE HYDROCARBON CONTENT IN SEDIMENT AROUND LAGOS AND NIGER DELTA 'AREA OF NIGERIA IN PPM ON DRY WEIGHT BASIS (BY GC) 419 54 THE HYDROCARBON CONTENT IN SEDIMENT AROUND LAGOS AND NIGER DELTA AREAS OF NIGERIA IN PPM ON DRY WEIGHT BASIS (FEBRUARY 1985) (BY GC) 427 55 THE-HYDROCARBON CONTENT IN SEDIMENT AT UTOROGU SWAMP AND OKPARI RIVER IN BENDEL STATE OF NIGERIA (PPM DRY WEIGHT BASIS) (BY GC) (OCTOBER- NOVEMBER 1984) 451 . \ 5o THE HYDROCARBON CONTENT IN SEDIMENT AT UTOROGU SWAMP AND OKPARI RIVER IN BENDEL STATE OF NIGERIA (PPM DRY WEIGHT BASIS )(BY GC) (JANUARY- FEBRUARY 1985) 4 54 57 THE HYDROCARBON CONTENT IN SEDIMENT AT UTOROGU SWAMP ’AND OKPARI RIVER IN BENDEL STATE OF NIGERIA (PPM DRY WEIGHT BASIS) (BY GC) (JUNE-JULY 1985) 455 58 THE HYDROCARBON CONTENT IN SEDIMENTS AROUND LAGOS LAGOON (PPM DRY WEIGHT BASIS) (JANUARY-DECEMBER 1985) (BY GC) ... 457 59 SUMMARY OF THE TOTAL ORGANIC EXTRACT AND TOTAL HYDROCARBON CONCENTRATIONS OF LAGOS LAGOON* NIGER DELTA AND UTOROGU SAMPLES (GRAVIMETRY AND GAS . CHROMATOGRAPHY) (jig g~1 DRY WEIGHT) 4 50 UNIVERSITY OF IBADAN LIBRARY XXXI Table Pa ge 60 SUMMARY OF TOTAL ORGANIC EXTRACT AND - TOTAL HYDROCARBON CONCENTRATION OF UTOROGU SWAMP.AND OKPARI RIVER (GRAY. AND GC).pgg-1 DRY WEIGHT 4 61 61 SUMMARY OF THE TOTAL ORGANIC EXTRACT AND TOTAL HYDROCARBON CONCENTRATIONS OF LAGOS LAGOON'SEDIMENT SAMPLES * (GRAVIMETRY AND GAS CHROMATOGRAPHY) (1985) (pg g-.l DRY WEIGHT) 4 6 5 62 SUMMARY OF THE DISTRIBUTION OF TOTAL ORGANIC EXTRACT (TOE), RESOLVED AND n-ALKANES, THE UNRESOLVED COMPLEX MiXTURE (UCM) TOTAL ALIPHAIIC, AROMATIC, TOTAL HYDROCARBONS AND MOPI IN SEDIMENTS OF ALL THE VARIOUS RIVER SYSTEMS STUDIED BETWEEN 1984- 1985 (pg g-1 DRY WEIGHT BASIS) 4 7 2 63 ; SOURCE CHARACTERIZATION OF HYD'RO- ' CARBONS FOUND IN SEDIMENTS FROM LAGOS LAGOON, KADUNA AND DELTA AREA OF NIGERIA (CONCENTRATION ug g-1) ... 494 64 SOURCE CHARACTERIZATION OF HYDRO­ CARBONS FOUND IN SEDIMENTS FROM UTOROGIJ SWAMP AND OKPARI RIVER (OCTOBER 1984) 500 65 SOURCE CHARACTERIZATION OF HYDRO­ CARBONS FOUND IN SEDIMENT FROM . UTOROGU AND OKPARI RIVER (FEBRUARY 1985) 501 66 SOURCE CHARACTERIZATION OF HYDRO­ CARBONS FOUND IN SEDIMENT FROM UTOROGU SWAMP AND OKPARI RIVER (1985 JUNE) 502 67 SOURCE CHARACTERIZATION OF HYDRO­ CARBONS FOUND IN SEDIMENTS FROM LAGOS LAGOON (1985) 504 UNIVERSITY OF IBADAN LIBRARY I xxx ii .Eole Page n-ALKANES AND UNRESOLVED COMPLEX MIXTURE (UCM) PARAMETERS OF SEDIMENT SAMPLES FROM LAGOS, NIGER DELTA, KADUNA AND IBADAN AREAS OF NIGERIA 52 S n-ALKANES AND UNRESOLVED COMPLEX- MIXTURE QiCM) PARAMETERS OF SEDIMENT SAMPLES COKFARI RIVER - 1984) 534 n-ALKANES AND UNRESOLVED COMPLEX MIXTURE CUCM) PARAMETERS OF SEDIMENT SAMPLES COKPARI RIVER', FEBRUARY 1985) ... 535 71 -n-ALKANES AND UNRESOLVED COMPLEX MIXTURE CUCM)" PARAMETERS OF SEDIMENT SAMPLES fQKPARI RIVER. 3RD SAMPLING) " 536 n-ALKANES AND UNRESOLVED COMPLEX ' MIXTURE (UCM) PARAMETERS OF SEDIMENT SAMPLES (LAGOS LAGOON, 1985) 538 '5 COMPARISON OF THE ALIPHATIC HYDRO­ CARBONS (BY GC) IN WATER AND SEDIMENT SAMPLES FROM SAME SAMPLING ' SITE 544 "4 COMPARISON OF PETROLEUM HYDROCARBON (ALIPHATIC FRACTION) LEVELS IN SEDIMENTS OF NIGERIA COASTAL WATER WITH SIMILAR RESULTS FROM OTHER ‘ COUNTRIES 549 UNIVERSITY OF IBADAN LIBRARY xxxi i i LIST OF FIGURES Figure Page 1 Scheme showing transformation of organic material to fossil fuels by reactions at varying temperatures ... ... 11 2 Types of hydrocarbons found in petroleum (Posthuma, 1975) ' 18 3 Some basic structures of S,N.O compounds in petroleum (from Posthuma, 1977) ... ... 31 4 A Polyhydroxyhopane ... ... 40 /, \i \ 4B m p ) h 2i (§>) h ... 41 4C 17 (*) H 21 ($ H . . . 41 5 The various processes which deter­ mine the fate and distribution of a pollutant added to the marine environment (Ketchum, 1970) ... 53 6 Petroleum hydrocarbons introduced into the oceans ... ... 65 7 Pathways of petroleum hydrocarbons in the marine environment 67 8 Fate of oil in the marine environment 82 9 The possible changes that can occur when crude oil is introduced into the marine environment ... ... 89 UNIVERSITY OF IBADAN LIBRARY / X X X I V ,-igure Page 10 Hypothetical mechanism for sensi­ tizer-induced free radical oxida­ tion in petroleum hydrocarbons. Gesser et al. (Environ.Sci.Tech. Vol,11, No.6, 8, 1977) 100 11 NNPC refineries, products pipeline network, depots and pump station covering the oil activity areas including the producing areas of the Niger delta ... ... 126 12 Flow diagram for analytical techni­ ques to detect and estimate petro- leum contamination ... ... 158 15 Analytical method for non-volatile hydrocarbons in ocean water - ^ . 159 14 Vertical water sampler 149 15 Horizontal water sampler ... 150 16 Van Veen grab for sediment sampling 154 17 Flow diagram for coupled liquid column chromatographic analysis 162 18 Comparison of typical separation from packed and capillary columns 255 ia Lagos and Lekki lagoons stations sampled in 1984-85 ... ... 274 2 € Niger delta station locations sampled in 1984-85 ... ' ... 275 21 Okpari river stations sampled in • -1984-85 ' ... 277 UNIVERSITY OF IBADAN LIBRARY x x x v *> 7 Lagos lagoon station where sediments were sampled in Jan-Dec. 19S5 ... 280 25 Ecological zones of the Niger delta 284 •The spectra of standard oil for infrared (1R) calibration ... 507 25 Calibration graph for oil in water by 1R spectrophotometric method .... 508 26 FID detector response for 'n-alhane at different concentrations . "... ' 524 47m 7i Gas chromatogram of n-paraffin mixed standard on 10% 0V-1Q1 326 T& Gas chromatogram of sample S-146-. - extract .... . . . 527 29 Gas chromatogram of sample S-146 extract co-injected with the mixed standard (C10~C36) , , ... 528 50 Chromatogram of a reference sample extracted by reflux method .... 34 8 31. Chromatogram of a reference sample extracted by soxhlet method 549 32 Gas chromatogram of n-paraffin mixed standard on 10% 0V-101 ... 550 33 ■ Gas chromatogram o.f n-paraffin mixed standard on 3% SE-52 ... 551 34 Mean level of petroleum in water of Lagos and Niger delta by river system (mg/1) > ... ... 381 UNIVERSITY OF IBADAN LIBRARY XXXVI Page Gas chromatogram of the hydrocarbon fraction obtained from the sediment collected from Orashi river system (Oguta Pontoon Crossing) ... 416 .Mean levels of petroleum hydrocarbons in sediment of Lagos lagoon, Kaduna and the Niger delta area by river system (in pgg~l dry weight of sediment) ... ... 4 74 Levels of petroleum hydrocarbons in Lagos.lagoon sediments (1985) ... 4 _ 5 Total hydrocarbon concentration (by IR) of water samples around Lagos and Lekki lagoon 0.984-1985), 478 Total hydrocarbon' concentration (by TR) of.water samples in the Niger delta (1984-85) ... ... 479 Aliphatic hydrocarbon (by GC) of sediment samples around Lagos lagoon ... ... 480 Aromatic hydrocarbon (by GC) of sediment samples around Lagos lagoon ... ... 481 Total hydrocarbon concentration (BY GC) of sediment samples around Lagos lagoon ... ... 482 Aliphatic hydrocarbon concentration (by GC) of sediment samples in the Niger delta ... ... 483 Aromatic hydrocarbon concentration (by GC) of sediment samples in the Niger delta ... • ... 4 84 UNIVERSITY OF IBADAN LIBRARY . xxxvii -F---i-- iss--u---r---e-- Page 45 Total hydrocarbon concentration (by GC) of sediment samples in the Niger delta . ... ... 485 4.6 Description of the marine oil pollution index (MOPI) ... 50 7 47 Chromatogram of a'-:p.etroleum con­ taminated sediment sample from Ogharife effluent canal * ... 511 48 Chromatogram of a sediment sample from Lagos lagoon showing weathered oil ... ... 512 49 - Chromatogram of sediment sample showing the -presence of both petro- genic and biogenic n-alkanes - . 513 50 Chromatogram showing a bimodal distribution of n-alkanes ... 514 51 Distribution pattern of hydrocarbon in some representative sediment samples ... ... 515 5 2 GC chromatogram of Bonny light crude 516 53 GC chromatogram of Bonny medium- crude * * % • • • 517 54- GC chromatogram of Brass crude ... 518 5fy GC chromatogram of Qua Iboe .... 519 56 GC chromatogram of Nigerian diesel 5 20 57 GC chromatogram of automotive gas oil (refined) t * « « » 5 21 UNIVERSITY OF IBADAN LIBRARY / xxxviii Figure Pag 58 GC chromatogram of Nigerian . petrol (refined) * « * * « * 522 59 ' GC chromatogram of kerosine (refined) * • • • • • 523 60 ’GC chromatogram of engine oil . ... s24 UNIVERSITY OF IBADAN LIBRARY CHAPTER ONE 1. INTRODUCTION 1.1 THE ORIGIN OF PETROLEUM . Crude oil has its origin in the organic debris of plants, algae, bacteria.,, fungi, and a multitude cf micro-organisms that have been deposited into aquatic sediments for a long time. The type of organic matter is dependent on the environment of deposition. Generally, marine, continental and puralic ('transitionai'~'betv»*een marine and continental) environments are colonised by different flora and fauna. Hence the corresponding sediments may contain grossly different types of organic matter. hhile marine biota are dominated by primitive plants and animals like planktons, algae, and diatoms, higher plants are preponderant in the continental shelf. Petroleum generated from different sources sometimes show gross dissimilarities in their content of certain classes of organic compounds due to the. varia­ tion in composition of proteins, carbohydrates, lignin, lipid, etc. of the living organisms from which they are formed. For instance, petroleum from marine source UNIVERSITY OF IBADAN LIBRARY 2 r:;ks are generally more aliphatic than their terri- , i ' :e~:us counterparts^ This-mainly reflects the :_££e.ence in the lower (lant -lipids£ ""-Hencehigh wax crudes are -rterally restricted to rocks deposited in continental and paralic or near shore-marine paleoenvironments rather than marine areas where higher plant influence is minimal^. In most aquatic systems, the rate of accumulation :£ organics in sediments is quite small compared to the primary productive rate in the surface water where -:st of the organic carbon produced is ultimately respired. In the presence of oxygen, bacteria degrada­ tion of organic debris takes place by the reaction0! UNIVERSITY OF IBADAN LIBRARY + C>2-- nCO + nl^O. V.Tiile in the absence of oxygen, anaerobic oxidation of organic material proceeds because certain bacteria utilize sulphate as a source of oxygen, according to the general reaction: CH^O + SO^---CO 2 +.H-0 + l^S. Further bacteria action continues with the reduction of carbon dioxide by hydrogen or attack by bacteria on such substrates as low molecular weight organic acids and methanol to produce methane. In oxygenated water, organic debris is oxidized relatively rapidly and extensively, so that little is preserved. In water lacking oxygen, on the other hand, organic debris is more likely to be preserved. The debris deposited in sediments also is subject to microbial attack, leading to further degradation, further breakdown of organic material likewise is :chanced in oxic environments by bioturbation which facilitates the diffusion of oxidants through the sediment, and by the presence of animal scavengers on .r within the sediment.. If sedimentation rates are identical in oxic and anoxic environments, the UNIVERSITY OF IBADAN LIBRARY 4 bioturbation that occurs under oxic water prolongs by hundreds of years the exposure of organic matter by oxidation, which strongly reduces its preservation and accumulation. However, in highly productive systems, or in systems with estuarine type circulation patterns or i % stagnant bottom water, anoxic conditions may develop in bottom \vaters and hence prevent or retard the oxida tion of detrital carbon. Such anoxic systems probably play an important role in the formation of oil. The widespread nature of oil deposits has suggested that significant amounts of oil may have been formed from organics that accumulated at the bottom' of normally oxidizing systems duringysedimentation^. Such organics, would necessarily have been rather refractory in nature. Since oxygen level in sediment generally drops to zero below a depth of no more than a few centimetres, any organics that are preserved suffi­ ciently long to be buried below a few centimetres of sediment would be efficiently removed from 'the possi­ bility of aerobic oxidation. Thus, the fi'rst step in the formation of oil presumably requires one or more UNIVERSITY OF IBADAN LIBRARY of the' followingo conditions'’. ' (a) The existence of anoxic bottom waters. (h) The production of refractory carbon compounds. (c) Rapid sedimentation. « ', 1.1.1 METAMORPHOSIS • . _ i ‘ V V. The organic carbon burred, in the sediment is ultimately incorporated into sedimentary rocks such as shales, sandstones, and carbonate rocks'. The organic carbon content of recently formed sedimentary rocks is on the order of no more than 0.1-10$ of the r o c k ^ \ The trapped organic carbon in these rocks is apparently the source of the world's petroleum reserves. There is a slow transformation of the carbon under conditions of elevated temperature (probably 10C--150UC) and pressure found deep under­ ground and perhaps through the mediation of catalysts such as aluminosilicate minerals. It has been suggested by Drsalvo et.•va l. 4 that Humic acids, 4‘ wh.i-ch are among the principal forms of organic carbon in sedimentary rocks, are probably the principal source of carbon for petroleum. UNIVERSITY OF IBADAN LIBRARY 6 i However, the presence of nitrogen and sulphur in virtually all crude oils indicates that other types of organic substances, are.also involved. The sequence of transformation that convert sedimentary organic detritus into petroleum is a continuous process and undoubtedly highly complex. By correia-' tion of the composition of crude oil with the age, it is possible to get- some idea of the sequence of / transformations that organic compounds undergo while buried in sedimentary rocks. In general there is a tendency for the higher molecular weight compounds to be broken down with time, leading to the formation of paraffins and ultimately to the production of methane and perhaps graphite as pnd products of the transfor­ mation. Thus, oil can he viewed as an intermediate stage in the breakdown of organic detritus under reducing (anaerobic.) conditions and under the influence of physical .and .chemical conditions (e.g. temperature, pressure, presence of catalysts)- peculiar to deeply buried sedimentary rocks.. In the geosphere, all deposited biomas’s undergo transformation in the first few hundred metres of UNIVERSITY OF IBADAN LIBRARY / f burial leading the conversion of the unstable bio- polymers to nitrogeneous and humic complexes which - constitute the insoluble Kerogen (Kerogen is the organic matter of rocks''that is insoluble in organic solvents, non-oxidising mineral acids and bases, which also yields one or mare hydrocarbons on heating). A small amount of soluble organic matter, bitumen, which might .be compositionally similar to crude oil, and sometimes referred to as protopetroleum is also formed. Organic matter (werogen) in sediments-occurs in many different forms, but can be classified into four main types&V" Liptinite Kerogen: have high hydrogen but low oxygen _ content due to the presence of aliphatic carbon chains. . They are considered to have been derived mainly from algae material (often bacterially degraded). They have high potential for petroleum. Exlnite Kerogen: contain a high hydrogen content / « (but lower than liptinites), with aliphatic chains and some saturated naphthene and aromatic rings and v oxygen containing functional groups. This organic UNIVERSITY OF IBADAN LIBRARY s matter is derived from membraneous plant materials such as spores, pollen, cuticle and other structured portion of plants. Exinites have a good potential for oil, can generate condensate and have a good potential for gas at higher maturation levels. Vitrinite Kero gen: have a low hydrogen content, high oxygen content and consist mainly of aromatic structure with short aliphatic chains connected byoxygen containing functional groups. . They are mostly derived from structured woody (ligno cellulose) materials and have a limited potential for oil, but a high potential for gas. Inertinites Kerogen: are the black opaque debris (high carbon, low hydrogen) that are derived from highly altered woody precursors. They have no potential for oil or gas. The main factors for recognition of a hydro­ carbon source rock are its content of Kerogen, its type of organic matter and stage of organic maturation. Good source rocks ideally require about 2-4 per cent organic matter content of a suitable type to generate and release their hydrocarbons. Under UNIVERSITY OF IBADAN LIBRARY 9 f . favourable geochemical conditions, oil can be generated from sediments containing liptinite and' exinite organic matter. Gas is usually generated from vitrinite-rich source rocks or by thermal cracking .of previously generated oil. ’ 1.1.2 MIGRATION The oil is formed over a much larger area and ultimately migrated to a localized deposit. The liquid petroleum once formed, could move upward through porous crustal materials until trapped by an impervious overlying substratum. Oil deposits are often overlaid by a pocket of gas (less dense than the oil) and invariably underlain by a reservoir of water (more dense than the oil). The existence of these two fluid in association writh an oil deposit simply reflects the tendency of fluid substances to migrate upw7ard through porous rocks until an imper­ vious substratum is encountered. The migration and pooling of oil has been essential for its storage over millions of years and hence for its abundance today. UNIVERSITY OF IBADAN LIBRARY 10 The most important characteristic of oil is the energy that can be derived from, burning (oxidizing) it. This energy was of course originally fixed via photosynthesis millions, of years ago and ha-s been stored in the chemical bonds of the organic substances of which oil is composed. The anaerobic transforma­ tions that lead to 'the formation of oil release some of the original stored energy, but a sufficient amount remains in the chemical bonds of petroleum to provide a highly useful energy source. The different reactions involved, in the conversion of organic materials into fossil fuels have been discussed by R. Paul Philip (3) (Fig. 1). -At temperatures below 50°C, many of the reactions are.chemical (such as condensation.) or biochemical and are referred' to as "diagenesis". As depth of burial increases and temperatures rise into the 50 to 200°C range, thermal alteration (maturation reactions) known as "Catagenesis" occurs. Ultimately, at temperatures above 200°C "metagenesis" of the organic natter takes place, converting any residual organic material, liquid or -solid, into methane and graphite. UNIVERSITY OF IBADAN LIBRARY i 11 CARBOHYDRATES, LIPIDS, PROTEINS, LIGNIN ' MICRC3BIAL ALTERVTION, to HYDROLYS:LS,< 50°C t1—o1 5 tz o SUGARS, AMINO • 1<—f ACIDS, FATTY ACIDS, PHENOLS CONDENSATION, CYCLIIATION, POLYMERIZATION, 50 °C ' NI'T ROGE1NO US AND n HUMIC COMPLEXES, KEROGEN t1o I 11 K THERMDCATALYTIC g CRACKING, & DECARBOXYLATION, ^ DISPROPORTIONATION, c5 50-200°C 1 ... ■ i PETROLEUM HYDROCARBONS, t1o LOW NDLECULAR WEIGHT, t—oJ. ORGANIC COMPOUNDS z ! g THERMAL CRACKING >200°C' h X HYDROCARBON, CASES 1— PYROBITUNEN, GRAPHITE Fig. 1; ' Schejne Showing Transformation of Organic Material to Fossil Fuels by Reactions at Varying Temperatures ~ UNIVERSITY OF IBADAN LIBRARY 12 1 • 2 THE NATURE OF PETROLEUM. (6)' The word 'petroleum' originates from the Latin word "petra oleum", rock oil. Petroleum varies in chemical composition, colour, viscosity, specific gravity, and other physical properties depending on • • - - - the source. The colour of petroleum varies from light yellow-brown to black and the viscosity varies from water-like to almost solid. The specific gravity of most petroleum oils lies between 0.735 and 0.950. 1.2.1 COMPOSITION^ 9̂ Crude oil is an exceedingly complex mixture,- composed of literally thousands of different kinds of organic molecules. Crude oils from different ■l ■ parts of the world may vary greatly in composition, depending on the age of the oil, the conditions of its transformation and so forth. Despite the com- plexing and variability of crude oil, some generalisa­ tion about its composition can be made. UNIVERSITY OF IBADAN LIBRARY 13 1.2.1.1 HYDROCARBONS Crude oil consists primarily of hydrocarbons. Some crude oils contain as much as 981 hydrocarbon by composition^^ . In addition to hydro­ carbons, the organic substances in crude oil include compounds containing sulphur, nitrogen and or oxygen, with sulphur being more abundant than nitrogen and nitrogen greater than oxygen. In addition, there are small concentrations of metals such as nickel, vanadium, iron, aluminium, sodium, copper and urani. um (11-12) Crude oils can be roughly characterized according to the relative amounts of the major kinds of hydro­ carbons they contain. The main classes of hydrocarbons found in crude oil are the straight-chain alkanes, the branched alkanes, the cycloalkanes, and the aromatics. Alkenes do not occur in crude oil. Combinations of straight or branched alkanes with either cycloalkanes or aromatic and of cycloalkanes and aromatics are numerous. Figure 2 shows the basic hydrocarbon struc­ tures found in petroleum. For a given carbon number the straight-chain alkane or n-paraffin is the most UNIVERSITY OF IBADAN LIBRARY 14 i abundant species found. Branched alkanes or iso­ paraffins occur in decreasing'quantities as the number of branches increases and as the branch point becomes further removed'-from the terminal end. The cycloparaffins or naphthenes usually contain a cycle- pentane or cyclohexane rin,g. Bicyclic and polycyclic naphthenes are also found. ‘ The aromatic portion of petroleum is usually less than the paraffinic portion as shown by Koons (13) for an "average” crude oil (Table 1). Aromatics occurs as single or multiple ring compounds with various alkyl substituents. Aromatics also occur in compounds such as tetralin where one ring is aromatic and the other ring is a cycloparaffin. The aliphatic hydrocarbons consist of the fully saturated normal and iso (or branched) alkanes of the general molecular formula (C v-’ith n ranging from 1 to usually around 40 although compounds with n > 60 carbons have been reported by Posthumaf Above C - 2̂ the most important group of isoalkanes are the isoprenoid hydrocarbons. (Pristane, Fig. 2) con­ sisting of isoprene building blocks. Pristane (C-̂ Q) UNIVERSITY OF IBADAN LIBRARY 15 TABLE 1: THE "AVERAGE" COMPOSITE::. C? criide~o i lCW~; ACvreurdeage By Molecular Size f t V - Gasoline - - 50 Kerosene (o-, q -C^?) - • io Light distillate oil ("C12 - CzOl' 15 Heavy distillate oil (C20_C40^ 25 Extremely heavy residuum oil 20 By Molecular Type Saturated hydrocarbons (normal and branched alkanes) 30 Naphthene hydrocarbons (cycloalkanes) 50 Aromatic hydrocarbons * 15 Polar (NSO) compounds 5 \ UNIVERSITY OF IBADAN LIBRARY 16 and phytane (C^q ) are usually the most abundant isoprenoids, while the to C^q isoprenoids are often major petroleum constituents, extended series of isoprenoids (C7q -C^q ) have been reported (1A) The saturated hydrocarbon class includes the aliphatic saturated hydrocarbons and the alicyclic alkanes consisting of compounds in which all or some of the carbon atoms are arranged in a ring. The vast majority of saturated ring structures, also called cycloalkanes or naphthenes, consist of important minor constituents which like the isoprenoids have specific animal or plant precursors^ W . g . steranes, diterpanes, andi.triterpanes (Fig. 2) and which serve as important molecular markers in post oil spill and geochemical studies . Aromatic hydrocarbons are usually less abundant than the saturated hydrocarbons, contain one or more aromatic (benzene) rings connected as fused rings (e.g. naphthalene) or linked rings (e.g. biphenyl). Petroleum contains many homologous series of aromatic UNIVERSITY OF IBADAN LIBRARY 17 t hydrocarbons consisting of unsubstituted or parent' aromatic structures (e.g. Phenanthrene) and. like . structures with saturated side chains, which replace a hydrogen atom in the ring with up to 10 or more carbon: atoms in methyl-type substituents. This higher degree of alkylation is most prevalent in two and three ringed aromatics although the higher polynuclear aromatic families ( 3 rings) do contain alkylated QL-3' carbons) side groups. The polycyclic aromatics with more than three rings consist mainly of pyrene, chrysenef benzanthracene, benzyp'yrene, benzofluorene, benzofluoranthene, and perylehe structures. The naphthenoaromatic compounds consist of mixed structures of aromatic and saturated cyclic rings. This series increases in importance in the higher .boiling fractions along with the saturated naphthenic series. The naphthenoaromatics appear related to resins, kerogen and sterols. The structures of some of the compounds described above are given irrfFigure 2 and Table 2. v UNIVERSITY OF IBADAN LIBRARY 18 n - ALkaNES CH4 c h3- c h3 CH,3 -(cH2„ ) n -CH_3 methane ethane n-alkane ISOALKANES (Hydrogen omitted) | l ! I - W - c W - -c1 -^i Tc-c 1 • - *c-1c- , 4 - ~9~ 4 - -9-, ' 4 - ) H -hopanes are bio­ genic in origin. The polyhydroxyhopane precursors shown in Fig. 4a have a 17(g,) H 2l(g,) H. stereochemistry (58) Fig. 4A: Polyhydroxyhopane. UNIVERSITY OF IBADAN LIBRARY I 41 and saturated hydrocarbons deriving from such precursors by low temperature diagenesis (as might occur in immature and unpolluted recent sediment) have also 17(p>> H. 2l(j£j '.H‘ or 17(oCpH' 21(̂ >> X stereochemistry, Figs. 4B and' 4C, but have only one C 2 2 isomer. UNIVERSITY OF IBADAN LIBRARY . This would give only one gas chromatographic peak for each hopane. homologue above C--, . In contrast, in oils, the- hopanes from C - ̂ to C._g show tv.'o gas chromatographic peaks. That is in members of the latter (mature) series with more than 30 carbon atoms, isomerisation has • taken place at to give a ’mixture of 22R and 2 2S isomers v^hich appears as a recognisable . fingerprint of doublets. However, in the former 17(Q A 21̂ £>) .H’ series, only one stereoisomer occurs at position 22 so that doublets do not occur. -- . 00 Petroleum also has a Pristane: phytane ratio near unity . y; All characteristics attributable to petroleum apply to refined petroleum products although the composition of distillate cuts are narrower in boiling range than the corresponding crude oil. Light distillate.cuts may contain olefinic material. One important interpretive caveat pertains to ite'E C. Smooth distributions of alkanes (CPI or --? = 1) within the crude oil rion-volatile boiling UNIVERSITY OF IBADAN LIBRARY range have been reported for marine bacteria by Ilan and Calvin and have been detected in marine / £ 1 \ fish by Boehm '1 - . Thus paraffinic tar and biogenic alkanes may be very similar in the C^q -C^q range. Furthermore, smooth n-alkane distributions have been noted in urban air by Hanser and Pattison(v f i? )^ and in laboratory dust samples by Gelpi et / £ O \ al.- . Thus, n-alkane distributions alone in environmental samples and especially in marine fish / cannot be attributable to oil pollution without corroboration by .other petroleum compositional features. 1 .4 CONCiiPT OF POLLUTION Marine pollution has been defined by a group of experts on the Scientific Aspect of Marine Polluticn (GESAMP) as "the introduction by man directly or indirectly, of substances or energy into the marine environment (including estuaries) resulting in suc* deleterious effects as harm to living resources, hazards to human health, hinderance to marine UNIVERSITY OF IBADAN LIBRARY 44 activities including fishing, impairment of quality for use of sea water and reduction of amenities” 64‘ . « It is not uncommon for all chemical wastes' discharged to the water bodies to be -regarded as ‘ V t. pollutants. This, however-, is a misconception since by international convention marine pollution is defined as stated- above. If chemical wastes are. dis­ charged in such a manner that they do not give rise to any of these deleterious effects, they cannot be regarded as pollutants. It must be recognised that any substance dis­ charged to the marine environment will have at least some small effect but whether the effect- is significant and deleterious is a matter of judgement which may depend on the use made of the receiving Waters. -In theory, it should be possible to use ecological techniques to assess the significance of any effects oh- marine life but in practice it is no simple matter to say whether they are deleterious since changes in the diversity and numbers of animals due to natural UNIVERSITY OF IBADAN LIBRARY 45 i causes are usually of much greater magnitude than those resulting from man's activities. By comparison with ecological techniques, it is a comparatively simple matter to measure the concen­ tration of constituents'of effluents in water, sedi­ ments and marine organisms using chemical methods an quite often when constituents are detected they are automatically regarded as pollutants although there may be no evidence whatsoever of determining effects It is only prudent to assume that these substances are pollutants, if , -for example, similar levels hav clearly been shown to be harmful during laboratory experimen. t. s 6 5• . • The pollution results from physical, chemical f. and biological factors. Domestic sewage, complex solutions of organic chemicals, organic materials entering natural waters from terrestrial ecosystem constitute the pollutants and are influenced by physical factors e.g. currents, vertical mixing and temperature stratification. Chemical properties include biological nutrients and poisons, soluble chemicals., and insoluble precipitate while the UNIVERSITY OF IBADAN LIBRARY 46 > b i o l o g i c a l vectors are - oxygen used in metabolism and trophic concentration. These factors combine together to alter the marine environment and desta­ bilize the marine ecology. 1.4.1 MARINE POLLUTION66 As human populi ations multiply and industrializ*a- tion increases and diversifies, the problem of the pollution of the environment becomes more critical. Pollution problems- mount as population move to the coasts seeking the amenities, and recreational opportunities of the sea shore, as well as' the con­ venience and advantages to be found there for certain kinds of industry. With the growing use of sea lanes for commerce, the ever-i'ncreasing size and variety of cargo ships and tankers and the use of the bed for mineral extraction, the threat of pollution to the marine environment from deliberate or accidental release of noxious materials from ships and cargoes becomes more acute everyday. The sea is also polluted by fall-out from the atmosphere.and large amounts of pollutants and wastes reach the oceans through the rivers and run-off from the land. UNIVERSITY OF IBADAN LIBRARY 47 i . Water is the usual recipient of human pollution in our environment. It is commonly the vehicle of pollution, and all too often the hydrosphere is the final repository or sink of pollution. There are some good reasons why this is so. To put a pollutant into the atmosphere usually requires a great deal of energy viz: gasification, combustion, vaporization', or of very 'fine pulverization. However, to put a pollutant into the hydrosphere or lithosphere requires very little energy. A pollutant is toxic or at least inimical to-the producer, thus pollution must he transported away from its point of origin. Pollutants are highly mobile in the atmosphere yet immobile in the lithosphere. Pollutants, such as solid wastes, deposited in the lithosphere, tend not to disperse and to accumulate eventually exhausting space in which to put them. However, pollutants dumped into the hydrosphere are also mobile and are readily transported away from the point of origin if they are soluble or dispersable, often to create a problem elsewhere. There is a pollution disposal dilemma in the process. We ;cant to get rid of the UNIVERSITY OF IBADAN LIBRARY / 43 pollutant to mobilize it, to disperse it. Yet the greater the mobility, the greate.r the dispersal, the greater the area contaminated^ ^ \ Now it appears that we may have entered into a new grim period in which global pollution of the hydrosphere of the world's oceans, has become a real threat. Lithospheric pollution alone tends to be local ai cont-ined, although leaching by ground waters, stream flooding, and so on, lithospheric pollution all too often can become hydrospheric pollution. Generally, the natural processes that remove pollu­ tants from the hydrosphere, unlike the atmosphere are much slower than the rates of input, especially cultural stress. Thus, (in addition to being the major vehicle for the transport of pollutants in our environment, the hydrosphere, notably the oceans, tends to become the sink or final repository where pollution accumulates. ^ 1 . 4 . 2 - THE FATE OF POLLUTANTS Preston e t . a l . ^ ^ and V.'idmark have tried to compile a list and classify some cf the more important pollutants that man dumps or leaks into UNIVERSITY OF IBADAN LIBRARY 49 i the oceans while Ketchum^ ̂ . has tried to represent diagramatically the major processes that determine the distribution and fate of pollutants in the marine environment. . Some of the organic pollutants both of natural (69) and synthetic origins from Widmark et.al. are shown in Tables 5 ('a) and 5(b). A sound knowledge of what becomes of the different pollutants being introduced into the aquatic environment is highly desirable for the understanding of their distribution and prediction of future pattern. For each pollutant, there are many possible patterns and interactions with the living and non-living components of the marine environment. y K e t c h u m ^ ^ summarized the various processes that will affect the ultimate distribution of a pollutant as illustrated in Fig.. 5. The favourable conditions for the disposal of waste, in the marine environment, are reflected through the dilution and dispersion of pollutants by turbulent mixing and ocean currents. Due to insufficient mixing, proper dilution of the waste fails to occur. UNIVERSITY OF IBADAN LIBRARY 50 / ' Pollutants may be concentrated by biological, chemical and physical processes. The concentration by biological processes may ultimately lead back to man as he uses the food resources of the sea. Bio-accumulation of chemical species occur with the marine organisms whereby they accumulate chemical - species in amount far above their concentration in the sea water. It has been shown that the organisms are highly selective in this respect 71 . Some species of tunicates (species of fish) have been found to accumulate the trace element Vanadium and Niobium from sea water. Other species of tunicates concen­ trate neither element. Some species of oysters are enriched in zinc some sea weeds in ruthenium. I. 2,2-bis(P-chlorophenyl)-1,1,1-trichioroethane (DDT) is concentrated from sea water by the higher gilled organisms. The processes involved in this accumula­ tion and specificity in the species are not well understood. UNIVERSITY OF IBADAN LIBRARY / 51 TABLE 5(A) :. ORGANIC POLLUTANTS OF NATURAL ORIGIN PARTLY CHANGED BY PROCESSING (TENTATIVE^69) Pollutants Comments Tannins Waste from dye industry. Lignin • Waste from paper and pulp mill industry. Carbohydrates Waste from paper and pulp mill industry, breweries, whisky industry \ ' ' and from sugar production. Oxygen consumption of local importance. Proteins, included Waste from slaughteries, dairies, and Peptides, Amino Acids, fish industry. Oxygen consumption of Amines, Fatty Acids, local importance. Lipids Hydroxy Fatty Acids Waste from the bark chipping of pine. HlelLc Acids \ ■ Pyrenthrines Insecticides. Terpenes Floatation of ore. Polycyclic Aromatic .Found, in marine organisms and Hydrocarbons (PAH) sediments, and in areas with volcanic activity. ---------------- -------------------------- ------ ------------ ----- ---- UNIVERSITY OF IBADAN LIBRARY 52 TABLE 5(B): ORGANIC POLLUTANTS OF SYNTHETIC ORIGIN (TENTATIVE/6^ Pollutants Comments Alkylbenzen Sulphonates (ABS) Detergent of the ''hard'' type, toxicity to marine organisms increasing with increasing branching. Not readily b io de gradab1 e. Linear Alkyl Sulphonates (LAS) Detergent of the ".soft" type, less' toxic to marine organisms than the former and more rapidly degraded by biological organisms. • Phenols In waste from industry, coke and gas works, also found in'natural seawater (1.3 pg/liter) . ■ Polycyclic Aromatic Hv4drocarbons From oil refineries, heating,' and so on. Aniline and Related Compounds From dye industries. UNIVERSITY OF IBADAN LIBRARY 53 ■ FIG. 5: The Various Processes Which Determine The Fate M d ■ Distribution Of A Pollutant Aided To The Marine Environment ̂ ' «, «* j - -v •_ UNIVERSITY OF IBADAN LIBRARY 54 f 1.5 SOURCES OF HYDROCARBON'S IX THE MARINE ENVIRONMENT7 2 ~ /6 • ' > Oil pollution is inevitably the consequence of the dependence of a growing population on an increasingly oil-based technology. The widespread production and transportation of oil and its use as fuel, lubricant and chemical feed stock leads to losses of different large magnitude and extent. Oceanic oil pollution has been a popular subject in governmental circles,, in the. news media, and in some technical journals. "Dialogue has been concerned mostly with the deleterious effects of oil spills or. near-shore ecosystems and beach properties. These dramatic short-term effects have masked interest in the disposal of some of the more soluble components of petroleum, such as the light hydrocarbons which may be transported downward via turbulent mixing of water masses and laterally by currents. These pro­ cesses lead to unnaturally high light hydrocarbon concentrations over areas much larger than the visible extent of the spills. Introduction of oil into the world’s ocean through UNIVERSITY OF IBADAN LIBRARY } 55 major spills accounts for several million tons of hydrocarbons released annually. Sourc.es of oil into the coastal waters include, tanker accidents, deballasting operations and tank washing as well as natural seepages and losses from off-shores production. Tank washing and accidents also release fuel oil and other refined products to the marine environment . Generally, hydrocarbon sources into the coastal and-marine environment can be grouped under three main headings, namely; (a) Biosynthesis; (b) Geochemical and (c) Anthropogenic inputs. 1.5.1 BIOSYNTHESIS Petroleum is formed from biogenic matter deposited in ancient seas, lakes and lagoons from natural precursors in organic-rich sediments. Although it is clear that most of the actual compounds found in petroleum result from diagenetic activities within the source rocks, it is clear that living organisms are capable of biosynthesising a restricted range of UNIVERSITY OF IBADAN LIBRARY 56 / 'natural' hydrocarbons, some of which are found in petroleum and some are characteristic of recent organic matter. Both aquatic and terrestrial organisms synthesise hydrocarbons either de novo or by conversion from other compounds (such as phytol to pristane). Phytoplankton produces normal alkanes in the range n-Cis ^g and ^ with n-C^ _ usually dominant . In the large brown algae (e.g. Laminaria) a single n-alkane, pentadecane (n-C^) predominates to the virtual exclusion of^ 1 1 other n-alkanes. Land P 1 ants contribute a vast input of hydrocarbon natter to.inshore waters. In such terrestrial plants the odd-numbered n-alkanes n !■ -C0z / ̂, -z, ny , z> ± , o o predominate, mainly m leaf waxes 4 6 Apart from these odd carbon- n-alkanes there are feic other hydrocarbons produced in living organisms which are also found in petroleum. However, there are several hydrocarbons found only in such .organisms, nbtably the unsaturated alkenes. These hydrocarbons may be released during meta­ bolism' or upon the death and decomposition of the UNIVERSITY OF IBADAN LIBRARY 57 organisms. 'Estimates of the rate of biosynthesis of •hydrocarbons by marine primary, productivity are generally given as 1-10 million metric tonnes per year u Recent studies also suggest the recent biogenic origin of certain cyclic alkanes. I.t .appears that pentacyclic triterpanes of the hopane type such as the 17 §3 (H)-hopanes are biogenic in origin and repre­ sent less stable forms of the 17QC> (H^-hopanes characteristic of petrogenic.sources (from early diagenesis). ,, ̂~"~ 1.5.2 GEOCHEMICAL PROCESS The geochemical processes responsible for the formation of crude oil lead to the production of an ■ * immense number of individual hydrocarbons, including many isomers and members of different homologous series. Each petroleum is an individual product v.hose composition reflects the chemistry of its source materials. In addition, it carries the indelible imprint of the geochemical subsurface processes that . have led to its formation. For certain classes of UNIVERSITY OF IBADAN LIBRARY / ss compounds, the compositional variability between crude oils is well known. Examples are the relative predominance of odd carbon number pai'affins and of the C-, c-iSoprenoia pristane in young (’immature*) cut not in older oils and the progressive .changes in the complexity of the multi-ring saturated and aromatic hydrocarbons with increasing thermal stress of the oil. M a n y •structures formed by living organisms (four and five ring naphthenes, porphyrins, etc.) survive in crude oil. Their composition is strongly affected by "the intensity of the chemical processes responsible for the formation of petroleum. Thus, the very small number of tetrapyrrole pigments may he coverted by geochemical processes into thousands of different fossil porphyrins whose structures are a unique reflection of the subsurface conditions. Submarine and co.asta) land-seeps release petroleum hydrocarbons to the marine environment. The annual input rate is variously estimated at: between less than 0 . 1 million metric tons and 10 million metric tons . A recent UNIVERSITY OF IBADAN LIBRARY 1 59 review of this subject has arrived at an annual input rate of 0 . 6 million metric tonnes per year(N11) Weathering of soils and sediments; including the mobility of some of the hydrocarbons in these .sedi­ ments to the marine environment also contribute co the oil input. Howeyer, the petroleum hydrocarbon con­ tribution from weathering is small relative to other sources because of slow degradation of the hvdro- carbons during the weathering process. No estimates of'the annual rate of input from these soutces are available. — There are chemical synthesis processes which are sources of hydrocarbons. Forest fires inject an estimated 6 million metric tonnes of hydrocarbons per year. (1 1 ) . into the atmosphere. An unknown portion is eventually delivered to marine environment. There are also chemical reactions occurring during the diagene'sis of organic matter in sediments which yield hydrocarbons. Diagenetic hydrocarbon constituents include: UNIVERSITY OF IBADAN LIBRARY 60 (a) Aliphatic hydrocarbons (b) Cycloalkanes (c) Sterenes (d) Polycyclic aromatic hydrocarbons (PAH), and (e) Pentacyclic triterpanes. One of the most significant sets of diagenetic products are the PAH compounds including some compounds which are also found in petroleum and other ,h yd, rocar. bon sources as we.l.l( 81 ) These diagenetic compounds may constitute important components of recent sediment hydrocarbon assemblages. Perylene and Retene are among those compounds formed in reducing sediment from higher plant precursors and which constitute major components of reducing sed,i. ment( 8 2 , 83 ) These hydrocarbons finally get to the marine environ­ ment either by submarine exposure of sediments or by diffusion out of the sediments. 1.5.3 ANTHROPOGENIC INPUT The largest source of oil entering the ocean is from the land, either directly from effluent pipelines UNIVERSITY OF IBADAN LIBRARY Cl i from refineries or petrochemical plants or from other discharges into river's. These may be waste oil put accidentally or deliberately into the water course or. the discharge of oily effluent from fac- * ' tories of all types. Automobiles use in total a great deal of oil. Some are burnt but some are dis­ charged as oil mist and some drip from the vehicle onto the road or car park. A great deal of used sump oil is also poured into drains or onto the ground by car owners doing their own maintenance. Oil from any of these sources is-'likely to arrive eventually in the sea. Even gaseous discharges can be \v7asiiea from the air by rain onto the ground and finally join the general run-off into the sea. The amount from this ' \ source is highly speculative. A more generally accepted figure for the run-off from land is 1.4 million tonnes per annum. Discharges directly into the sea from tankers and other ships can be divided into four main groups: Operational discharges from tankers during tank washing; 2 . Bilge discharges; UNIVERSITY OF IBADAN LIBRARY i 62 3. Spills caused by marine accidents, collisions, groundings, etc. 4. Spills during loading, discharging or bunkering. , Tank washing used to be the major cause of marine pollution from ships. If all the residual oil left in the tanks after normal discharge is washed out, about '0.3 per cent of the cargo will be so discharged. Improved methods of tank washing (load-on-top and crude oil washing) have been'introduced, which have greatly reduced the total amount of oil discharged in this way. The increase in the price of crude oil has given an added incentive to reduce the loss of oil from tank washing. All ships take in small amount of water which collect in the lower parts of the vessel or bilge. Oil fuel, used for firing boilers and oil used for lubricating can leak or be spilt and enter the engine- room bilges which are periodically pumped out. Oil- water separators are now being used in most vessels to reduce the amount of oil escaping into the sea through this route. UNIVERSITY OF IBADAN LIBRARY 63 Several authors like Porricelli and / O C \ Keithv y have reviewed the available statistics concerning losses due to tanker accidents, covering various periods and different ranges of ship size, and found the results to rat-e from 0.05 to 0.25 million tonnes per annum. There are major variations in total spillage from year to year depending on the occurrence of major accidents. The most recent and complete study strongly suggests that the rate of spillage is at the upper end of the range. The data on non-tanker accidents are scanty. There are about nine times as many non-tankers as tankers, but their aveiage size is much smaller; also, the only oil normally carried in them in bulk is bunker fuel. Reported estimates for the annual rate of loss range from 0 . 0 2 million tonnes per annum tp 0.'25 million tonnes per annum (mta). • 7 Figure 6 and Table 6 depict the amount of oil introduced into the marine environment from different sources. River run-off constitutes the major pathway UNIVERSITY OF IBADAN LIBRARY 64 followed by tankers and bilges bunkering. Industria wastes, municipal wastes and urban run-off contribut equally to petroleum hydrocarbon source into the marine environment. Pig. 7 depicts the pathways of petroleum hydrocarbons in the municipal environment. UNIVERSITY OF IBADAN LIBRARY 65 Fig, 6 : Petroleum Hydrocarbons Introduced Into The Oceans,(«) UNIVERSITY OF IBADAN LIBRARY 66 TABLE 6 : ESTIMATED ANNUAL INPUTS OF OIL TO THE OCEANS, 1978 • Source MillionTonnes % Load-on-top tankers 0 . 1 1 2 . 2 2 Non-load-on-top tankers 0.50 1 0 . 1 0 Bilges and bunkering 0 . 1 2 2.42 Terminal operations 0 . 0 0 1 0 . 0 2 Dry docking 0.25 5.05 Tanker accidents 0.30 6.06 Non-tankers accidents 0 . 1 0 2 . 0 2 Sub-Total (1.381) Off-shore oil production 0.06 1 . 2 1 Coastal oil refineries 0.06 1 . 2 1 Industrial waste 0.15 3.03 Municipal waste 0.30 6.06 Urban run-off 0.40 8.08 River run-off 1.40 2 8.28 Natural seeps 0.60 1 2 . 1 2 Atmospheric rain-out 0.60 1 2 . 1 2 Sub-Total (3.57) Overall Total 4.951 UNIVERSITY OF IBADAN LIBRARY 67 / Fig. 1 ■■ Pathways Of Petroleum Hydrocarbons In The Marine Envir UNIVERSITY OF IBADAN LIBRARY f 6S 1 . 6 ' AIR POLLUTION FROM THE USE OF PETROLEUM 1.6.1 ' INTRODUCTION •Air pollution can be defined as the additions to our atmosphere of any material(s) having a deleterious effect on life. Typical air pollutants include things such as carbon monoxide (CO), nitrous oxides (NOx), sulphur oxides (SOx), and various hydrocarbons and particulates. They -can be one of two types: 1. A primary pollutant, or one lethal as it originates from -the source; or ' - 2. A secondary pollutant, one formed through the reaction of primary pollutants (this reaction can occur at the emission point, or at far removed localities). Air pollution is generated by six major types of sources: (Table 7) 1. Transportation 2. Domestic heating 3*'"' Electric power generating 4. Refuse burning 5. Forest and agricultural fires 6. Industrial fuel burning and process emissions. UNIVERSITY OF IBADAN LIBRARY 69 TABLE 7: INDUSTRIAL SOURCES OF AIR POLLUTANT EMISSIONS( 86) Type of Industry Type of Emissions 1 . Petroleum refining Particulates, sulphur oxides, hydrocarbons, CO. 2. Smelters for A1, Cu, Particulates, sulphur oxides. Pb, Zn 3. Iron foundries Particulates, CO. 4. Kraft pulp and Particulates, CO, sulphur paper mills oxides. 5. Coal cleaning and Particulates, CO, sulphur refuse oxides 6. Coke (for steel Particulates, CO, sulphur manufacturing) oxides. 7. Iron and steel mills Particulates, CO. 8. Grain mills and grain handling Particulates 9. Cement manufacturing Particulates. 1 0 . Phosphate fertilizer plants Particulates, fluorides. UNIVERSITY OF IBADAN LIBRARY / 70 * -- It is necessary to also examine the effects of these air pollutants on animals (including man), on.' plants, and or materials, as well- as the meteorolo­ gical effects. / a * 1.6.2 EFFECTS ON MAN Health Effects . Many of the common air pollutants *can have very serious effects on human health. For example, CO is known to contribute to heart disease. Considering all sources of pollution, especially transportation, it is one of the major, if not the major, pollutants, and is also one of the most difficult to eliminate. It is formed during the combustion of carbon- containing compounds whenever there is a lack of oxygen (0 2); 2C + O 2 — f»2C0 (in limited C^) . C + C>2 — & C0? (in excess 0 ?). This substance affects the central nervous system even in very low concentrations, by forming ca-rboxy- haemoglobin in the bloodstream, which interferes with the normal transport of oxygen to the body UNIVERSITY OF IBADAN LIBRARY / 71 cells 8 6 . Two per cent carboxyhaemoglobin is enough to generate observable effect's, and can be formed by an S-hour exposure to only 10 ppm CO. Oxygen transport is clearly affected at 5% carboxyhaemoglo- bdn, generated at CO levels of 50 ppm or greater. Heavy automobile traffic can generate' 50-140 ppm CO, and the smoking of cigarettes can create up to 15® carboxyhaemoglobin. .In addition to the immediate effects of poor oxygen transport, high carboxy­ haemoglobin levels tend to make a person retain cholesterol in the aorta. The sulphur oxides SO 2 and SO- are generated primarily in the combustion of high sulphur fuels. The sulphur oxides are toxic to the human body, especially disease such as emphysema.^ ' They can also accentuate viral pneumonia. The sulphur oxides usually can be detected by their odor, but prolonged exposure may desensitize a person to these compounds. Theoxides of nitrogenNO and N0 2 .are usually found in-much lower concentrations. They are generated only in high-temperature combustion situations, and hence have been referred to as an elitist pollutant, UNIVERSITY OF IBADAN LIBRARY 72 t only present in technologically advanced societies. Their ultimate effect on humans is not clearly understood, but they do act as irritants to breathing, and create discomfort to the eyes. X0 7 c&n also destroy the celia in the respiratory system and suppress alvero]ae macrophage activity, the lung's final defence against foreign matter. Recent studies of various nitrogeneous air pollutants have indicated that these compounds may be more serious health hazard than one thought. In particular the peroxy nitrates are quite stable at lower air temperatures, and may be more important pollutants than Ozone* Peroxyacetylnitrate (PAN) is. created by photochemical reactions involving hydrocarbons. PAN has a general structure of 0 0 I! I R - C - O - O - N - O where R stands for hydrocarbon chain of varying lengths (CH^-CK^-CH^- A typical formation mechanism would be as follows: UNIVERSITY OF IBADAN LIBRARY 73 0 u II !l R - C - R UV R° + R c a hydrocarbon (ja ketone) 0 . 0 K C — 0 _ m NO 0 w 0 R - C - 0 - 0 N( 0 < (PAN) - Some PAN are generated naturally, for coniferous vegetation is a major source of hydrocarbons and NO 2 is prevalent everywhere. NO can also react with some polycyclic aromatic hydrocarbons in laboratory /g y\ tests to produce mutagenic compounds1 '. There are hundreds of hydrocarbons which form air pollutants. Many of them are possibly carcino- genic and might be at least partially responsible for the current increase in lung cancer. UNIVERSITY OF IBADAN LIBRARY I 74 Particulates have various adverse effects, dependent upon their size. ■ » Cl) Below 0.1 pm, the major effects relate to weather modification. This is the most likely «*• 1 size to induce nucleation of water droplets. (2) Between 0.4 and 0.8 pm-, the diameters are approximately equal to the wavelength of light, and thus lead to the greatest restriction of vi• si• bt. i• li i- t. y 8 8 C_3) Between 1 and 5 pm, there is a maximum • deposition in the lungs upon inhalation. C.4) Between 3 and 15 pm, the particulates are deposited in the upper respiratory system. C.5) Between 10 and 100 pm, the particulates create ' * dust and dirt. Those particulates which are inhaled are damaging to respiratory systems. In addition, they may be toxic. For example, mercury and other heavy metals lead to direct biochemical reactions. The particulates may end up deposited in the lungs, causing a build-up on the lung lining. This could result in a disease called silicosis. This build-up on the lungs reduces UNIVERSITY OF IBADAN LIBRARY 75 the ability of. the lungs to transfer oxygen into the blood. The normally elastic and spongy lung tissues harden, reducing the lung’s breathing efficiency. In order to pump an adequate oxygen supply; the heart must then work • harder. This leads to shortness of breath, possibly to an enlarged heart, and eventually to premature death! f In addition, particulqfes can sometimes cause excessive mucus secretion as a protective reflex. This excess mucus can restrict the bronchiole tubes and lead to bronchitis'. The worst condition for human health is from the combination of particulates with a high SO 2 concentration. A large percentage of- the SO-, in the Z \ atmosphere is due directly or indirectly to natural sources (volcanoes, decay vegetation, sea spray, etc. The SO 2 generated naturally is, however, so dispersed over the world that it never builds up to dangerous levels. Man’s. SO2 contribution - the "anthropogenic" SO2 - tends to be concentrated in industrial and urban areas, and hence can rise to dangerous levels. The SO2 in the air, often with particulates acting as UNIVERSITY OF IBADAN LIBRARY a catalyst, can be converted to SQ-: 2 SO 2 + ® Particulates7 - M S O - The particulate surfaces can provide a reaction site for.the formation of SCX to occur. The SO- can readily react with water vapour to produce sulphuric acid (I^SO^) . Thih acid can easily damage lung tissues. In the atmosphere, some of the sulphuric acid droplets can react with ammonia Q\TH-) to generate solid ammonium sulphatre, CNH^^SO^. In 1948, Donora, Pennsylvania experienced large deaths because the concentration of acid sulphate salts C^inc ammonium sulphate and zinc sulphate) was high in the atmospher around the area. The H 7SO^ in the air gets washed down whenever it rains, generating "acid rain". Acid rain has been linked not only to damaged trees and other plants, increased weathering and corrosion of materials and ,—̂ buildings, and water pollution problems, but also is possibly an added threat to human health 89 .' Acid rain is also formed from NO emission, which can react UNIVERSITY OF IBADAN LIBRARY 77 to form nitric acid (rLNO_) in the atmosphere. Recently, acid rain was declared as possibly "the. most severe environmental problem of the century. i.6 .3 EFFECTS ON ANIMALS The'health effects of the various pollutants on animals are much the same as their effects on humans. In addition, insecticides may also be a major problem to animals. Frequently, their food sources become contaminated by one form or another of air pollutant. Many pesticides can be carried right through the food chain. For example, if a pesticide is sprayed over a large area, much of it ends in a lake or stream for consumption by fish. The fish can be eaten by certain types of birds., which can then be affected. Chlorine containing pesticides have, for Instance, been related to thinner than normal eggshells in fish-consuming predatory birds. The thin eggshells lead to breakage before the eggs hatch, and hence to a loss of those offspring. UNIVERSITY OF IBADAN LIBRARY / 78 1 .6 . 4 .EFFECTS ON PLANTS The major pollutants whi-ch affect plant life are the primary pollutants SO,, and hydrogen fluoride (HF), and the secondary pollutants 0 - and PAN. • ' SO 2 can have either chronic or acute effects 1 on plant life. An initial bleaching of plant cells and a stunting growth often leads to death. PAN is very reactive toward the nitrogen in plant materials, probably disrupting the bond in protein molecule. - ' Particulates usually lead to photo-'-toxicity inhibition of respiration and/or photosynthesis. 1 .6 .5 METEOROLOGI1 CAL EFFECTS \ ’ Air pollution can have a major effect on the climate, both regionally and globally. Regionally, rainfall can be drastically altered by the presence of air pollution. The formation of rain in the air involves collection of moisture in the tiny droplets, using a particulate as the nucleus. These tiny droplets UNIVERSITY OF IBADAN LIBRARY 79 i t initially collect and form clouds. If a sufficient concentration of moisture is present, the droplets can attract more water vapour to themselves and grow in size and eventually form rain. The presence of the particulate thus catalyzes the initial moisture condensation and droplet formation. Because of thi.s behaviour, air pollution can also have the opposite influence on precipitation. Too many particulates can encourage the formation of too many small, nuclear particles compared to the available .moisture. Each, particle cannot attract enough water vap.our to itself, so, it cannot grow enough to form rain droplets. The net effect is a decrease in precipitation. 1 • 7 THE PHYSICAL , CHEiMICAL AND BIOLOGICAL FATE OF OIL IN THE MARINE ENVIRONMENT There have been several extensive reviews of the fate of oil in the marine environment. The major processes which act on crude oil or oil products spilled on water are essentially four different modes of d, egrad, at. i. on 9 0 -9 2 UNIVERSITY OF IBADAN LIBRARY 80 (1 ) Evaporation (2) Dissolution (3) Microbial degradation and (4) Chemical degradation. When petroleum spills on the ocean, it immediately begins to disperse. The rate of disper­ sal depends on a variety of environmental factors such as the speed of the wind, size of the waves, temperature, salinity, water depth, and currents and on the nature of the oil, its specific gravity, degree of refinement, and the quantity involved (93) Theoretically , the oil will spread- •.. : .. : - - until it is a mono-molecular layer, but this tendency is counteracted by viscosity and other forces. According to Blokker^^, the thickness of a uniform oil slick decreases exponentially with time. The viscosity, density, chemical composition, pour point of the oil, the wind speed and current will influence the rate of spread. Emulsification reduces the tendency of the oil to spread' . UNIVERSITY OF IBADAN LIBRARY 1 . 7 . 1 E V A P O R A T I O N When oil is released on to the ocean surface (e.g. as a slick) it spreads: quickly. There is a selective depletion of .the lower boiling components of an oil, but this leads to little or no fractiona­ tion among hydrocarbons of the same volatility that belong to different structural series. Most un- weathered crude oils have a smooth boiling point distribution over a rather wide range, due to the non-selectiye, random nature of the geochemical processes that are involved in petroleum formation. There is a logarithmic dependence of the boiling point on the molecular volume. Evaporative losses decrease rapidly for higher members of homologous series 8 . ' • . - Evaporation removes the most volatile materials first, and then progressively the higher-boiling • compounds.. Low-molecular-weight compounds such as monoaromatics are lost. Since these volatile compounds include the more toxic hydrocarbons, the longer the dispersion period, the lower the residual toxicity of the oil C_Fig. 8) . ' UNIVERSITY OF IBADAN LIBRARY 8 2 G* .FATE Oh Oil IN THE MARINE ENVIRONMENT 'lb DURCEr JOHN. ST ON C S UNIVERSITY OF IBADAN LIBRARY 85 1 In the case of a blow-out, the oil is hot and much often than 30-50% is lost by immediate evaporation before it hits the sea surface. Evaporation is analytically apparent from the gradual lowering of the boiling point curve (or chromatographic peaks first at low and then at increasingly higher molecular weights. '1.7.2 DISSOLUTIONS This is thermodynamically related to evapora­ tion, at least as faiyas the least polar hydrocarbons are concerned. Quantitatively, its effect resembles that of evaporation, it is evident principally from the loss of the low boiling and at the same time more soluble hydrocarbons.' However, the preferential solvation and the greater water solubility of aromatic and heterocyclic hydrocarbons, especially those of lower, molecular weight enhances their dissipation relative to the saturates of similar molecular size. The-' distinction between the effects of evaporation and of dissolution is not always easy and may require detailed analysis, e.g. by-mass spectrometry of the UNIVERSITY OF IBADAN LIBRARY 84 i • aromatic fraction. Again, it is the lower-molecular-weight hydrocarbons which are the most soluble in water. Also, degradation products of the larger molecules can be more polar and thence have greater solubility. Thus again, the more toxic compounds tend to be dispersed preferentially, which means that in an area of good dispersion, there is a rapid decrease in risk to marine life. Rates of dissolution for the various components of a petroleum siick "depend on rather complex interactions between properties inherent to the oil (that is, molecular structure of compounds and relative abundance of tfyese components) and the physio--- chemical properties of the immediate environ­ ment (that is, salinity, temperature, etc.). Xot only does this complex interaction of compositional and environmental factors, exist for rates of evaporation, the overall rate of slick disappearance depends on interactions between evaporation and dissolution processes(96). Many studies have provided data to define UNIVERSITY OF IBADAN LIBRARY ss solubility as a function of molecular structure, principal determinants of solubility for any particular petroleum hydrocarbon include the mole­ cular volume fexpressed as cm "V mole) and the presence of "active" groups fe.g. aromatic rings or olefinic bends]. Solubility is generally inversely proportional to molar volume, which is a linear function of carbon number, .Roughly, the solubility decreases by a factor of three per carbon number, hut linearity of this■relation falls off for n-alkanes above n - C ^ Q ^ Branched alkanes demonstrate•greater solubili­ ties for a given carbon number than their-straight- chain counterparts, and this.seems to be due to . increased vapour.pressure relative to corresponding compounds, as opposed to a structural function. Ring formation also enhances solubility for a given carbon number or molar volume. The degree of saturation is inversely proportional to solubility for both chain and ring structures. The addition of a second or third double bond increases solubility proportionately, and it has been shown that the UNIVERSITY OF IBADAN LIBRARY 86 presence of a triple bond increases solubility to a greater proportion than presence' of two double bonds. Therefore, the most water-soluble petroleum hydrocarbons will he those with the lowest molar volume and greatest aromatic/olefinic character. An inverse relationship exists between salinity I and hydrocarbon solubilities for both aliphatic and aromatic components, writh an approximate decrease of for-n-paraffins between fresh and seawater^'". Table 8 lists the solubilities for some aliphatic. anc aromatic petroleum hydrocarbons in distilled water and sea water (35°/00 _+ 0.5) at 25°C. For the paraffins, the magnitude of this "salting-out" effect is directly proportional to the molar volumes in accordance with the McDevit-Long theory 1 0 w? , w’hich attributes "salting in" or "salting out" to the effect of electrolytes upon water structure. Dissolved organic matter in the marine environ­ ment enhances solubility, due to its surface-active nature ] 03 . One study, utilizing natural mar-ine water and NaCl solutions, examined .the effect on various hydrocarbon solubilities due to removal of the UNIVERSITY OF IBADAN LIBRARY 87 TABLE 8: SOUJBIIITIES OF ALIPHATIC AND AROMATIC PETROLEUM HYDROCRBONS IN SEAWATER AND DISTILLED WATER AT 25 °c(1027 Compound Solubility in Solubility in Distilled Water Sea Water Dodecane (C^2 ) 3.7 ppb 2.9 ppb Tetradecane (C1i4y) 2.2 ppb 1.7 ppb Hexadecane (C,i)o) 0.9. ppb 0.4 ppb Octadecane (C1Q) 2.11 ppb 0.8 ppb Eiocosane (c2 q) 1.9 ppb 0.8 ppb Hexacosane (C„Z,o) 1.7 ppb 0.1 ppb Toluene 534.814.9 (ppm) 379.312.8 (ppm) Ethylbenzene 161.210.9 ppm 111.011.3 ppm O-xylene 170.512,5 ppm 129.611.8 ppm M-xylene 146.011.6 ppm 106.010.6 ppm P-xylene 156.011.6 ppm 110.910.9 ppm Isopropylbenzene 65.310.8 ppm 42.510.2 ppm 1,2.4-Trimethyl— LKinzeue 59.010.8 ppm 39.610.5 ppm 1,2,3-Trimethyl- benzene 75.210.6 ppm 48.6+0.5 ppm 1,3,5-Trimethyl- benzene 48.210.3 ppm 31.310.2 PR.m n-Butylbenzene 11.810.1 ppm 7.0910.0 ppm s-Butylbenzene 17.610.2 ppm 1 1 .9 1 0 . 2 ppm t-Butylbenzene 29.510.3 ppm 21.210.3 ppm UNIVERSITY OF IBADAN LIBRARY 88 dissolved organic matter, A 50 to 99" decrease in the amounts solubilized was observed for n-alkanes • and isoprenoids, with the decreases being directly proportional to the amount of dissolved organic ma»tter removed (e.g. by activated. charcoal and UY oxidation). However, the .aromatics examined (anthracene, phananthrene, and dibutylphthalate) were unaffected by this process. 1 .7.3 MICROBIAL (BIOCHEMICAL) DEGRADATION Microbial degradation of crude oil appears to be the natural process by which the bull: of the polluting oil is eliminated . Under anaerobic conditions, oil is preserved, whereas in the presence of oxygen, microbial degradation takes place. The first step of microbial degradation is to convert the hydrocarbon molecule to a fatty acid. This results in the so-called chocolate mousse (Fig. 9) and a colloidal effect that acts to further the rate of microbial degradation and disperse the oil in the sea. In areas that are well aerated and where the microbial population is adapted to oil influx, the rate of o il UNIVERSITY OF IBADAN LIBRARY 89 vs*y stow FIG-9’. THE POSSIBLE CHANGES THAT CAN OCCUR WHEN CRUDE OIL IS INTRODUCED I NTO THE MARINE ENVIRONMENTS) UNIVERSITY OF IBADAN LIBRARY 90 t oxidation at 20° to 30°C may range from 0.02 to 0 2 .Og of oil oxidized/m^/day^ ^ 5 ) ^ Numerous strains of bacteria, yeasts, actinomycetes, and filamentous fungi have been reported to utilize various types of Individual hydrocarbons^^, but analytical difficulties restricted the number of quantitative studies on petroleum biodegradation. Given favourable conditions, micro-organisms Kill degrade a substantial portion (40 to 80 per cent) of a crude oil, but the degradation is never complete’ n--alkanes . are utilizea preferentially and highly hrancKed alkanes, cycloalkanes, and aromatics are utilized with difficulty; and mixed enrichments are more effective in petroleum degradation than . ' isolated cultures CTahle 9) . Among the factors that are believed to limit oil degradation in the sea are the nature of the oil involved, the number and type of micro-organisms present;,, the temperature, the low level of some .—^ mineral nutrient in seawater, the oxygen tension, the salinity, the surface tension, and the pH*107 UNIVERSITY OF IBADAN LIBRARY 91 Nitrogen and phosphorous (available as N 0 ?, NO-, Nh ! and PO"? 1 have been shown to be limiting factors to both rates and extents of petroleum compound degradation, as well as having a stimulating effect by' addition of nutrient supplements ( e : g . CNHj) - SO ̂ and K-HPCh) to. the immediate experimental environment 108 . Iron is now known to become limiting when precipitated out of the environment as ferric hydroxide, under alkaline conditions. However, both the natural abundance of iron in the lithosphere and marine pH ranges would probably prevent this limita­ tion from occurring. The environmental temperature can affect degrada­ tion rates by acting upon the microbial populations in several ways. Ambient temperature will select for microbial, species tolerant to the temperature range present, such as psychrophilic bacteria with optimal growth rates from 15°-20°C. Thus, qualitative shifts may occur within the microbial population (and in the inherent petroleum degradative capacity), as reflected by the relative presence of hydrocarbonoclastic microbes. Low temperatures generally suppress UNIVERSITY OF IBADAN LIBRARY 92 degradation rates by suppressing growth rates and metabolic rates of the microbes involved and/or by . actually- inhibiting growth, due to increased reten­ tion of toxic component's in the petroleum. Inhibition due to toxic volatile compounds that evaporate more slowly at low temperatures, or to the increased solubilities' of potentially toxic petroleum compounds at higher temperatures may occur 109-113 Microbial degradation attack compounds over a much wider molecular weight range than evaporation and dissolution.^ In general, hydrocarbons within the same homologous series are attacked at roughly the same rate. This is in sharp contrast to the logarithmic dependence of evaporation and dissolution on the molecular volume of the hydrocarbons. The ease of bacterial degradation decreases in the order n-alkanes, iso-alkanes, cyclo-alkanes, aromatics ̂ ^ . ; Analytically, microbial degrada­ tion is most readily apparent from the decrease in normal alkane concentration, relative to more resistant v components of similar boiling point and solubility. UNIVERSITY OF IBADAN LIBRARY 95 TABLE 9: MICRO-ORGANISMS CAPABLE OF OXIDIZING/CO- OXIDIZING PETROLEUM HYDROCARBONS AND/OR THEIR DERIVATIVES Organism Type Species Name Source Environment(s)a Bacterium Achromobacter >v>. T.M. , Â _ Cycloclastes (T, M) b • Acinetobacter sp. T,F,M,MS Aeromonas sp ’ M , MS Alcaligenes sp A. eutrophus Bacillus-naphthlinicum • beljerinekia so Brevibacterium sp . T,M B healii (T,M) Cellulomonas galba Cornybacterium sp T,M Flavobacterium sjp FS,M UNIVERSITY OF IBADAN LIBRARY 94 t TABLE 9 (coutd.) Organism Type Species Name Source Environment (s)a Bacterium Micrococcus Cerificans Mycobacterium sp • >MS M. r h o d o c h r o u s • - Nocardia sp M,MS N. Coeliaca (M,MS) N. coralina (M,MS) N. minima"- (M,MS) N . opaca (M,MS) N. salmonicolor (M,MS) Pseudomonas sp T, F, M ,MS f. P. aeruginosa T,F,M ,MS P. desmolytica FS(T,F,M,MS) P. desmolyticum (T,F,M,MS) P. fluorescens (T,F,M,KS) P. Ligustri (T,F,M,MS) P. methanica (T,F,M,MS) \ UNIVERSITY OF IBADAN LIBRARY 95 TABLE 9 (contd.) Organism Source Type Species Name Environment(s)a Bacterium P.. oleovorans (T,F,M,MS) P. orvilla (T,F j M ,MS) P. ips1eudomaleii (T,F,M,MS) P. putida FS(T',F,M,MS) ' P. testcsterni (T,F,M,MS) Serratia marinoruba gtreptonyces sp • Vibrio sp T,M,MS ■ Yeast . Candida petrophilium (F ,M) C. trophicalis M,F Endomycopsis lipolytical M,F \ Fungi filamentous Aspergillus versi color - Cephalosporium Acremonium . UNIVERSITY OF IBADAN LIBRARY 96 TABLE 9 (contd.) Organ:’ 5 3 Type Species Name .Source Environment(s)a F&ingi* Cladosporium resinae T,F,M • filamentous Cunningham elegahs * .Penicillum zonatum P. ochro-chlorens Algae Prothotheca zophi M SOURCE: OIL SPILLS. a. T = terrestrial sediment; M = Marine water column F = Freshwater MS = marine bottom sediment; FS = freshwater bottom sediment. b. Key letters in parentheses designate the genus being indigenous to the specified environment. UNIVERSITY OF IBADAN LIBRARY 97 1.7.4 CHEMICAL DEGRADATION 115-116 When oil is subjected to autoxidation or photo­ oxidation, there is chemical transformation of its components. Sunlight initiates free-radical reactions that convert hydrocarbons into hydro­ peroxides. These hydroperoxides are then further transformed to alcohols, acids and other oxygenated compounds. The free-radical reactions also lead to the polymerization of the partially oxidized hydrocarbons. The resulting 'tar' is denser, more polar, and more viscous than the parent .hydrocarbons . Photosensitizing compounds, such as Xanthone, 1-naphthol and other naphthalene derivatives have been shown to increase photo-oxidation rates for petroleum hydrocarbons. Compounds suitable as sensitizers must have strong absorption properties in the visible (or near UV) region, which results in a formation of a singlet or triplet state with a sufficient lifetime and energy to initiate free- radical chain reactions capable of proceeding at low temperatures. Obviously, this compound must also be UNIVERSITY OF IBADAN LIBRARY 98 lipophilic and stable to oxidative processes within th, e oil-water system (118) Xanthone has been determined to be most effec­ tive sensitizing compound in n-hexadecane photo­ oxidation. A Type I photosensitized oxidation mecha­ nism has been suggested, (Fig. 10). Light induces formation of triplet state xanthone via intersystem crossing from the excited singlet, which then extracts a hydrogen atom from n-hexadecane (forming a free-radical alkane). The xanthone-hydrogen complex interacts with molecular oxygen to reform the photosensitizer, accompanied by formation of a hydroperoxide radical. This, radical then can interact further with other alkanes, which can then combine with molecular oxygen to form peroxides which can decompose to oxygenated radicals. These radicals may then interact with other alkanes to form alcohols. Inhibition of photo-induced oxidation occurs via chain terminating reactions. Qrgano-sulphur compounds present in the petroleum are oxygenated to sulphoxide products by way of terminating the free radical chain reactions, and thus they inhibit complete oxidation UNIVERSITY OF IBADAN LIBRARY 99 to carboxylic acids. Thus, preliminary evidence that the toxicity of Nigerian crude oil is not greatly affected hy exposure to light could be ascribed to high levels of sulphur in the crude as compared with refined product 3 ^ ^ The initial reaction rates may be influenced by the presence of dissolved metal ions of variable valence which act as catalysts, vanadium, for example is a common trace metal in petroleum and strongly catalyzes oxidations in the aqueous phase<95). 1 .7.5 EMULSIFICATION Within the water, emulsification remains the predominant dispersion process. It takes two main forms. Oil-in-water emulsion is formed on the surface and then dispersed hy currents and waves; water-in-oi.1 emulsion contains compounds of high molecular weight and is commonly called "mousse". It can contain up to 80?« water, depending on the type of oil UNIVERSITY OF IBADAN LIBRARY I 100 TYPE I PHOTOSENSITIZED OXIDATION MECHANISM FOR PETROT Pm< HYDROCARBONS: X ■ •+ h-V - A n > X * IS 0i - - - 0 X* * ♦ X** + RH --d> XH° + R° XH° + °2 •r - - ! > X + H02O R° + l °2 P.02o - * R02o + RH R02H - i R° R°2° -i- XH° R02H + X R0,,H H > R0° + °0H z . ----------- RH ROH + R° R02H Ro R0° + ROH+ I. X Xan thone, X* Xan thone Si ngl e t. x** = Xan thone tripl e t. RH = n^hexadecane. TS C = Interlays tern crossing. FIG. 10: Hypothetical mechanism for sensitizer- in d*iced free-radical oxidation in petro­ leum hydrocarbons, Gesser et al . ~ UNIVERSITY 7o0 O - oF + IBADAN LIBRARY 101 ) Natural o r _added surface-active substances induce one or the other type -of emulsion. Furthermore, a not negligible fraction of crude oil (containing atoms of N.p S, 0, P) having surface- active properties may play an important part in the dispersion of oil product?. The suspended particles in the sea (oxides, hydroxides, carbonates, clays) also play a role in the dispersion by stabilizing or disrupting the emulsion The use of chemical surface-active agents to break up oil slicks so that marine, land and air species do not become impregnated with oil has been highly contested. The surface-active agents increase the probability, that droplets of hydrocarbons will meet particles suspended in the water, and volatile hydrocarbons which might otherwise have been eliminated from the marine environment by evaporation or dissolution will thus be deposited on the, sea floor. The dispersants used on the coast, in particu­ lar for clearing up mobile substrata, can act as vehicles for the oil and allow it to infiltrate deeply, which compromises biodegradation and UNIVERSITY OF IBADAN LIBRARY 102 contaminates burrowing species, years afterwards, old and totally inert hydrocarbons can be found on beaches. 1.7.6 FORMATION OF TAR LUMPS Stretching over a very long period, hydrocarbons which have not been degraded in the first two phases (microbial and chemical degradation) are found in different parts of the marine environment in the form of virtually stabilized agglomerates (tar lumps), accumulates in living organisms or in the mobile substrata. Tar lumps consist of very heavy hydro­ carbons (up to C^q ), oxygen, nitrogen or sulphur compounds and mineral compounds (35°a), especially iron oxide ( 91 ) 1.8 PATHWAYS AND TOXICOLOGICAL HFFECTS OF PETROLEUM POLLUTION Petroleum and its compounds which have been released into the environment are eventually degraded into simple compounds of their constituent elements by physio -chemical or biological agencies, with or without human assistance. They become innocuous; but UNIVERSITY OF IBADAN LIBRARY 1 0 5 1 i . • - in the process, may cause serious damage to plants and animals or their physical surroundings and thus impede human exploitation of natural resources. The effects of oil pollution also vary widely according to the history of the spillage, the nature, of the locality and the state of its biota. An oil pollution incident may interfere directly with industry or commerce, spoil the enjoyment of amenity pursuits or affect natural processes seemingly u n ­ connected with human affairs. It should be remembered that every influence which, however, remotely dimi­ nishes the richness and variety of our environment ultimately diminishes the fullness and perhaps even the span of our lives. 1 . 8 . 1 EFFECTS QF OIL POLLUTION ON LAND The nature of terrestrial oil pollution ranges from a massive single spillage resulting, for example, from a split or overflowing storage tank, overturned transport vehicle or fractured pipeline - through the small, but perhaps repetitive, losses which often arise from careless handling at small UNIVERSITY OF IBADAN LIBRARY / 104 ‘ factories and similar installations, or the surrep­ titious dumping of their waste, oils, to such con­ tinuous but usually small-scale sources as an un­ detected -leak or an oil-contaminated flow-of waste water. Storm water carries from vehicle-parks and heavily-used roads a quantity of lubricating and other oils which is usually ignored, but which can be a significant source of local■pollution. Although the site of any given incident cannot normally be predicted, most pollution is nevertheless, restricted to the immediate vicinity of areas where petroleum is produced, processed, transported or used, since spilled oil rarely spread far in the terrestrial environment.I. The first noticeable effect of oil spilled across the surface of the land in any quantity is likely to be upon vegetation. Plants exchange the gases involved in respiration and photosynthesis through small pores, mostly on the underside of their leaves. Some specialist plants of waterlogged, anaerobic soils also transport air from these pores to their, roots, improving the soil condition locally1 2 -1. The UNIVERSITY OF IBADAN LIBRARY / 105 pores may readily be penetrated by thin oils, a process which is usually demonstrated by a darkenin of the leaf as its air-spaces become filled with the oil; heavier fractions may block them up, while a«coating of dark oil excludes or filters the sunlight necessary to the functioning of all green plants. Once it has received a significant covering of an active oil, an individual leaf invariably dies. Oil percolating into the soil around the roots may inter­ fere with their uptake of water or cause the release of substances toxic fo the plant. The damage w’hich might be caused by a widespread spill of the more toxic or penetrating oils is indicated by the fact that selected blends have been used as herbicide sprays in their own right in addition to their frequent use as a medium for speci- fic herbicidal substances (122 123) • On the other hand, some light fractions have little toxic effect and have been used against plant fungal diseases or as solvents for insecticide sprays with little or.no damage to crops or livestock. UNIVERSITY OF IBADAN LIBRARY • bC 10b 1.8.2 EFFECTS OF OIL POLLUTION ON AQUATIC ORGANISMS*124,125) The effects of oil pollution can be grouped under two categories: (a) The effects associated with coating or smothering of an organism with oil;such effects are associated primarily with the higher molecular weight, water insoluble hydrocarbons, the various tarry substance that coat the feathers of birds and cover intertidal organisms such as clams, oysters, and barnacles. Tube worms are surpris­ ingly little affected by such coating*,124 ̂ although the effect on organisms such as aquatic birds may be devastating. (h) Disruption of an organism's metabolism due to the ingestion of oil and the incorporation of hydrocarbons into lipid or other tissue in sufficient concentration to upset the normal functioning of the organism. With respect to this second effect, it is generally agreed that aromatic hydrocarbons are the most toxic, followed by cycloalkanes, the olefins, and UNIVERSITY OF IBADAN LIBRARY 107 lastly alkanes. There is also a definite tendency for the toxicity per unit molecular weight to decrease as the molecular size of the ,h yd, rocarb, on increases ( 124 ) The toxicity with respect to the second category closely parallels their solubility in water. Thus, the most toxic components and also the most soluble in water are the low molecular weight aromatics such as benzene and toluene. Whereas the least toxic and least soluble are high molecular weight alkanes, aromatics and other toxic hydrocarbons apparently exert their effects in part by becoming incorporated into the fatty layer that makes up the interior of cell membranes ^ . As a result, the membrane is disrupted, and ceases to properly regulate the exchange of substances between the interior and exterior of the cell. In extreme cases the cell membrane may lyse, allowing the contents of the cell to spill out and obviously destroying the cell. Although the low molecular weight alkanes and cycloalkanes were once UNIVERSITY OF IBADAN LIBRARY 108 considered to be harmless to aquatic life, it is now known that these compounds can cause narcosis and anesthesia in a variety of lower animals (^6) ̂ Such effects are probably due in part to disruption ofr cel„l membu ranes(124) Hydrocarbons also interact with proteins in a variety of animals. Both enzymes and structural proteins appear to be affected. Once again, aromatics seem to be more toxic than other hydrocarbon classes with respect to this effect. • The relative toxicity of various types of oil can be deduced from the above information. Refined petroleum products such as gasoline or kerosene contain virtually no high molecular weight hydrocarbons, and hence exert very little in the way of a smothering or coating effect. However, because refined products do contain a higher percentage of low molecular weight hydrocarbons than crude oil, these products exert greater second-category type toxic effect than does a comparable amount of crude oil. In this respect, it is noteworthy that two of the most ecologically damaging oil spills, the grounding of the UNIVERSITY OF IBADAN LIBRARY / 109 tanker Tampico Marti off Baja, California in 1957, and the grounding of the tanker Florida in Buzzard Bay, Massachussetts in 1969, involved spillage of refined petroleum, namely diesel oil and No. 2 fuel oil respectivel-y1 2 7 . ■ Crude oil on the other hand contains a signifi- cant fraction of hiigh molecular weight hydrocarbons, which give it a viscous, sticky character. As a result, the greater damage from crude oil discharges may be the first category sort, that is the coating of- plants and animals with, high molecular weight hydrocarbons. Undoubtedly the organisms most affected by oil coating or "oiling" are certain kinds of aquatic birds, namely awks (murres, guillemots, razor bills, puffins, etc.) penguins and diving sea ducks. These birds are particularly susceptible to oiling for the following reasons: (1) They spend most of their lives on the surface of the sea. (2) They are poor fliers or are flightless'. (3) They dive rather than fly in response'to a disturbance. UNIVERSITY OF IBADAN LIBRARY 110 When oil is adsorbed to the feathers and down of these birds, their plumage becomes matted, and the air spaces which normally provide buoyancy and insulation become filled with water and oil. They get drowned due to their inability to maintain a proper body temperature without adequate insulation from their plumage. Invariably oiled hirds attempt to clean themselves by preening their feathers, but in the process, they may ingest as much as 5090 of the oil in their plumage and die from toxic effects of the ingested oil. A list of various suhlethal effects on the physiology, histology, and behaviour of organisms and on their populations are described in Table 10. The suhlethal modifications may affect the characteristics of the populations of each species, changing the rates of birth, death, and dispersal, as well as the age structure and spatial pattern. Also, changes in the ecological communities may occur in the affected area. Potentially carcinogenic hydrocarbon components of crude oil occur in the marine environment, and are accumulated or retained in marine animals, and then by UNIVERSITY OF IBADAN LIBRARY Ill man..’ The belief that oil can induce cancel in.n^frine organisms is based on the fact that polycyclic, aromatic hydrocarbons have been identified as carci­ nogenic agents. They are widely distributed over the ocean and are found in crude oil; and they concen­ trate in animal tissues. Cancer has been found in clams from oil spill sites. However, there has been no conclusive evidence to date implicating oil as the direct cause of the observed neoplasms. It has been observed that not all aromatic hydrocarbons but only particular configurations (e.g. Phenanthrene , Chrysene and Benzo(a) Pyrene) have carcinogenic potency and that many animals (e.g. Macoma inquinata, a detritus feeding clam and Abarenicola pacifica, a burrowing polychaore) can transform these to less harmful- forms (Phenanthrene could be conjugated into ■ highly polar metabolites). Mixed function oxidases (MFO) such as aryl hydrocarbon hydroxylases (AHH) capable of coverting benzo(a) pyrene into polar metabolites, Have been found in several polychaetes, e.g. Nereis sp. and Capi tella capitatav ’ ' r UNIVERSITY OF IBADAN LIBRARY 112 • Ingested hydrocarbons tend to become fixed in tissues containing fat reserves, such as the liver, the pancrease in invertebrates, or the gall bladder; but also in .the lipoproteins in plasma and all cutaneous and nervous tissues. . Ry affecting cellular mechanisms they may cause cutaneous changes such as necroses or tumors. According to Halstead, 12% of a sample of 16,000 sole from San Francisco Ba• y p• resented an average of 55 tu*m■ ors per fish in the vicinity of petrochemical waste disposal sites. Parry and Yevich in 1975, demonstrated frequent neoplasma in shell-fish (Menidia nenidia and Mya arenaria) contaminated by insoluble and soluble fractions of oil from Texas and Louisiana and gonadal and nematoporetis neoplasms in 2£% of animals collected on the coasts of the State of Maine which are permanently polluted by hydrocarbons. Polycyclic aromatic compounds are also formed naturally by micro-organisms and are not necessarily associated with oil from spills. Concentrations of benzopyrene in marine organisms may nevertheless reach 400 ppb along highly industrialized coasts, The risk of UNIVERSITY OF IBADAN LIBRARY 113 TABLE 10: EVALUATION OF EXPERIMENTS AND OBSERVATIONS OF THE SUB LETHAL EFFECTS CW* ORGANISMS BOTH QF POLLUTION AND OF OTHER ASSOCIATED"ACTIVITIES OF THE PETROLEUM INDUSTRY ' Type of Group Species Reference Petroleum Product Concentration Effects and Evaluation A Reproduction Fecundity Crustacea Pollicipes Straughan, 1971 Crude oil, Santa Inverse relationship between the fraction of Polvmerus Barbara blowout field adults brooding and the amount of oil on the study adults (p.0.5); heavily and moderately oiled areas had no recruitment whereas settlement was recorded from all unoiled samples. Mollusca Mvtilus edulis Blumer et al, No. 2 fuel oil, West 1971 Falmouth spill field Gonads of mussels failed to develop in affected areas observations Fish Godus morrhua Kuhnhold, 1970 Iranian crude Aqueous.extracts Eggs: "Some cases" were sublethal but embryos and extracts (paraffin from 104 ,103, larvae did not survive, apparently, lO^ppm does based) 10^ ppm total not differ from control. Larvae: "Showed typical oil (author behavlbr Symptoms'in oil extracts; increased estimates iO4 activity was..followed by a reduction of swimming- activity, which finally stopped... which slowly., yields 10 ppm deepened until the 'critical point' when no > soluble hydro­ responses of the*larvae were obtained even by carbons, 1 ppm touching or prodding": time to "critical point1’." varies with age of larvae and amount of oil: 10^)pa may be more not.-different from control- 114-5.5 days’for 1«1Q likely. day old. larvae); l Q ^ a (8.4r4.5; lO^ppn (4.2^0.5); "herring larvae were less, ana plaice larvae more resistant than cod"; "chemoteceptors seemed to be blocked very quickly at the first contact with oil"; insufficient quantification; no measure of uncertainty; no chemical analysis Lobster Homarus Wells, 1972 Venezuelan crude 0.1,1,6,10, and 100 cpn lethal to all larval stages; lOppm ; stage americanus .00 (emulsions) 1-3 more sensitive than stage 4. Long- term experiments with newly hatched larvae. 10 phm. 9-day mean survival time; 6upp. longer time to 4th longer than at lower concentrations; concentration at which development was prolonged are too high to be important in the field UNIVERSITY OF IBADAN LIBRARY 114 TABLE 10 (contd.) Species Reference Type of Group Petroleum Product Concentrations Effects and Evaluation 3 Growth Chore11a Kauss et al., Aqueous extracts of Phytoplankton 1 part oil to 20 1973 several crude oils parts water Inhibition of growth varied from 5 to 41% after r vulgaris and outboard motor 2 days of exposure; after 10 days, ceil yields oil; 90% solutions were close to controls, suggesting inhibiting of aqueous substance was eventually lost. After 2 days of cell extracts used growth, cell numbers were significantly lower in 25,50, and 90% oil extracts than in control: con­ centrations of water-soluble hydrocarbons and comparison of oils unknown C Metabolism Photosynthesis Phytoplankton Mixed natural Gordon and Venezuelan crude 10-200 g/(ppb) samples Prouse, 1973 No. 2 and No. 6 Concentrations below 10-30 (2g/l were found to fuel oil stimulate photosynthesis, while at concentrations between 60 and 20 0 ilg/1, were somewhat suppressed below controls for all but No. 2 fuel oil which depressed photosynthesis to approximately 60% of controls at concentration between 100 and 200)tg/l environment in Bedford Basin: 0.5-60 g/1; highest content (under slick): 8 0 0 g/1 2 Respiration Fish Cyprimodon varie Steel and Petrochemical gatus lagodon Copeland, 0wastes in . 2a-d2d.i0tpicomn Clams respiratory inhibition at low concentration 1967 0.4-4.0 phenol then stimulation approaching IL48 as general Micropogon pattern; only 1 of the 3 species fit this pattern; undulatus insufficient acclimation; too high concentrations Fish Juvenile 3rocksen and Benzene 5 and 10 prun Onchorhynchus Bailey, 1973 changed every Respiratory rate was increased during the early tshanysha 48 h (24-48-h) period of exposure to both 5 and of.benzene;Jafter longer periods', respiration, (salmon) and decreases back to near-control levels: when Morone saxatilis tested at daily intervals after exposure, found (striped bass) both fish species returned to control levels 3 Behavior Fish Ictalurus natalis Todd, 1972 Feeding unaffected; social behavior altered after 1-3 days and returned to normal in about 1 week second additions after return to normal again disrupted social behavior UNIVERSITY OF IBADAN LIBRARY 115 TABLE 10 (contd.) Group Species Reference Type ofPetroleum Product Concentrations Effects and Evaluation Crustacea Homarus Atema and Stein, La Rosa crude and Chane in feeding times (doubling of waiting time) americanus 1972 extracts thereof and behavior caused by addition of 1:100,000 parts crude oil to water: soluble fractions giving same oil/water ratio had no effect; light and electron microscopy showed no change in morphology of odor receptors; response similar over 5-day period, although hydrocarbons' characteristics did change by "weathering"; experimentally good as possible, but long-term effects and recovery not considered: very difficult problem E Histological Changes Fish Menidia menidia Gardner, 1972 Texas-Louisiana Llw/40 1 Various types of histological abnormalities exhibited crude oil seawater, then after exposure to both the soluble and insoluble separate fractions: largely chemoreceptor structures studies fractions but also ventricular myocardium; no analyses of (soluble and concentratons seen by fish; technique seems good, insoluble); but tissue and water content of hydrocarbons needed exposed for 168 h D Behavior (continued) Fish Gulf of Mexico Bechtel and Petrochemical Different % Claims that percent polluted water is a good species Copeland, wastes Houston predictor of species diversity; unfounded because 1970 Ship Channel confounded with salinity; to convincingly demonstrate water that oil pollution responsible for decreased diversity, compare with samples covering a similar range of salinites in an unpolluted control bay UNIVERSITY OF IBADAN LIBRARY 116 increasing contamination in the products of the sea is thus real. 1•9 OIL_ SPILLS: A GLOBAL PICTURE Oil spills, particularly on the sea and Navigable Waters, have excited more public interest and concern than any other waste or spilled materials, even if the latter are potentially or actually far more hazardous. These accidental spills, constitute a small fraction (3 to 4 per cent) of the annual rate of addition of petroleum into the marine environment. Some of these spills occur within confined marine areas, such as bays or estuaries where the concentra­ tion may remain high for extended period causing the biological impacts to be greater than if the oil were released where rapid dispersion could take place. Such releases are generally large compared with chronic low-level additions and, furthermore, they commonly occur in coastal waters where man makes maximum use of marine resources. A list of some of the more important oil spills is given in Table 11. UNIVERSITY OF IBADAN LIBRARY 117 TABLE 11: MAJOR OIL SPILLS (1957-83) 1 29 Type and Date of Source & Location Amount of Nature of Spill Oil Incident (Barrels) March 1957 "Tampico Maru" 55,220 Baja California, No. 2 fuel Mexico oil Grounding July 1962 "Argea Prima" 70,000 Guayanilla Harbor, Crude oil Grounding Puerto Rico. January "Chryssi P." 1967 Goulandris, ^1,800 Milfold crude oil Haven, England March 196/ "Torrey Canyon" 821,000 Cornwall S.W. Kuwait Grounding England oil September "R.C.Stoner." 1967 126,000 Wake Island Aviation gas J-P4 Jet fuel A-l Grounding turbine oil and Bunker C oil March 1968 "Ocean Eagle" 83,000 San Juan, Harbor, Puerto Crude oil Rico Grounding UNIVERSITY OF IBADAN LIBRARY 118 TABLE 11 (contd.) Type and Date of Spill Source & Location Amount of Nature of Oil Incident (Barrels) April 1968 "Esso Essen" 20,GOO- S. Africa 28,000 Crude oil December "Witwater" 20,000 1968 Galeta Island, Diesel and Canal Zone Bunker C oil January Well A-21 33,OuO 1969 Santa Barbara Crude oil Blowout Channel, USA January Santa Barbara 70,000 - 1969 oil rig 700,000 Blowout offshore Santa Asphaltic Barbara Crude California, USA September "Florida" barge 1969 West Falmonth, 6,000 NO.8 Buzzard Bay diesel fuel Massachussets, USA t ebruary "Arrow" 108,000 1970 Chedabucto Bunker C Grounding BSy,USA • February Chevron oil Rig 30,000 1970 Offshore Gulf Gulf crude Blowout of Mexico December Shell oil rig off 53,000 1970 Louisiana Coast Gulf crude Blowout near Grande Isle, La, USA UNIVERSITY OF IBADAN LIBRARY 119 TABLE 11 (contd.) Type and Date of Spill Source & Location Amount of Nature of Oil Incident (Barrels) January San Francisco 27,100 1971 Bay,Below Bunker C Tanker Golden Bale oil Collision Bridge, USA January Arizona 1971 Standard and Oregon standard 20,000 san francisco Bunker C bay USA oil February "Wafra" 1971 445,000 Cape Aulhas Crude oil S. Africa April 1971 March point dock facility, Anacortes, 5,000 Washington No. 2 USA Fuel oil October Amoco oil rig 1971 400 Gulfoffshore Louisiana coast, Crude USA ' Blowout January General M.C. 3,000 1972 Meigs, Wreck Navy Cove Washington Special Collision Coast, USA oil 1976 Urguiola 60,000 Struck an La Coruna Crude Underwater in Spain oil obstruction UNIVERSITY OF IBADAN LIBRARY 120 TABLE 11: (contd.) Type and Dace of Source & Location Amount of Nature of Spill Oil Incident (Barrels) 1976 Jakob Maersk 80,000 (contd) Oporto in Crude Portugal oil Metula Straits of Magellan in B5u0n,k0e0r0 C Chile oil December Ven oil and 1977 ven pet port Elizabeth, S. 30,000 Collision Africa December Ekofisk North 80,000 1977 Sea Norway Crude oil Grounding March 1978 Amoco Cadiz 220,000 Portsall Light Brittany Coast Arabian Grounding France oil 1979 Ixtoci compuche 2,700,000 Bay Mexico Crude oil Collision 1983 Sivand East 104,000 Coast of Humber, Nigeria Collision Britain Crude oil I UNIVERSITY OF IBADAN LIBRARY 121 The ecological effects of these spills depend largely on the type of oil involved, the quantity, the physical, chemical and hiological states of the impacted area. These effects include the possibility of: (1) Human hazard through eating contaminated sea food. (2) Decrease of fisheries resources or damage to wildlife such as sea birds and marine mammals. (3) Decrease of aesthetic values due to unsightly slicks or oiled beaches., (4) Modification of the marine ecosystem by elimination of species with an initial decrease in diversity and productivity. (5) Modification of habitats, delaying or preventing recolonization. Apart from the global incidents shown in Table 11, a record of some accidents in West and Central Africa is also ayailable as can be seen in Table 12 below. UNIVERSITY OF IBADAN LIBRARY 122 TABLE 12: OIL SPILL INCIDENTS IN WEST AND CENTRAL AFRICA, 1975-1980 INVOLVING SHIPPING 129 Type and Date of Source & Location Amount of Oil Nature of Spill (Barrels) Incident 12/17/75 Mobile Refiner 45 tons Collision Douala, Cameroon bunker fuel 4/lo/77 Universe Defiance Unknown Explosion off Senegal quality in engine bunker fuel room 10/2o/77 Uniluck (not Unknown tanker) 4 miles Quality from Louche Fuel oil Grounding Island, Nigeria 11/01/77 Arzen cotonou 50-5,000 Fire while (Dahomey) Product discarging o/21/79 Petro Bouscat 20 Fuel oil miles south of quantity Grounding Douala ' Cameroon 8/16/79 Loannis Angeli Ship discharge Louanda, Angola Crude unknown Grounding (6o 16’S quantity lio 3310 litre sample. Extract sample^Jith 25 to 125 ml tetrachloromethane IR measurement of Extractable organics Reduce sample to 2 ml by controlled Evaporation of CCl^, Add 0.1ml of n-pentane. silica Gel column separation. I CCl^ + n-pentane (1%) CHClj + Benzene (1%) Saturatet Hydrocarbons Aromatic^Hydrocarbons Evaporate CHC1,, n-pentane and Benzene, Replacing with CC1, 1 IR measurement of Total hydrocarbons I evaporate CCl^, replacing with isooctane to final volume 'v-4ml. 31__ IIV analysis .. Evaporate isoOctane to-- 0.5 ml. -------- ------------- G C, Ms Analysis FIG. 13: ANALYTICAL METHOD FOR NONVOLATILE HYDROCARBONS^109^ IN OCEAN WATER. UNIVERSITY OF IBADAN LIBRARY 140 2.2 SAMPLING, CHOICE OF SAMPLE AND SAMPLE PRESERVATION INTRODUCTION The solubility of hydrocarbons in water is low; the lower alkanes and aromatic hydrocarbons being the most soluble. Oil in water is therefore likely to be present either as droplets or in association with particulate matter due to its organic nature, and it can be implied from this that its distribution will not be uniform. The low solubility of the hydrocarbons means that even for those in true solution, a further difficulty in sampling is caused by their tendency to adsorb on to the inner surfaces of the sampling equipment. This not only reduces the apparent concentration in a sample, but if not removed from the sampler, the hydro carbons will remain to be desorbed into a future sample of lower concentration. Sample collection for baseline studies in the sub-part per billion to part per million concentration range from pristine environments, requires that every possible precaution be taken to minimize contamination UNIVERSITY OF IBADAN LIBRARY 141 ana sample handling errors. At these ultra-low concentrations it is imperative that a creditable sampling programme be designed in order to obtain meaningful results. The quantity of sample required depends on the analysis to be undertaken. A representative sample should be drawn for oil determination and the size of sample wiLl depend on the anticipated oil content. 2.2.1 WATER Water is an important medium in the dispersion of oil. Solubility of crude and refined petroleum products in water varies for type of crude and products, the heavier fractions having less soluble components than the lighter fractions. Mckee et a 1 (135) -statecj that the solubility of modern petrol in water is in the range of 20 to 80 mg/1 (with mean value of 50 mg 1 . However, soluble hydrocarbons in water give rise to objectionable tastes and odour 136 at concentration as low as 0.001 mg l” . The aromatic fraction which is a toxic component of petroleum is soluble in water to an extent that can UNIVERSITY OF IBADAN LIBRARY 142 be detected with a reasonable accuracy. In order to evaluate the danger to which the aquatic plants and- animals are being exposed, the level of hydrocarbons in water is very important and must be determined. x This will help in our bid to protect the quality of our environment. 2.2.2 SEDIMENT Crude oil on landing on water spreads over wide areas with very limited mixing with the water. When , / it spreads in this manner, volatile substance escape rapidly while water soluble materials disperse and the material remaining is subjected to bacterial degradation. Certain portion combine with silt and sink to the bottom, where they are incorporated into the sediment. Occasional mixing allows the re- entrying of the hydrocarbon into the water and for the bottom feeders to feed on the contaminated particles. Marine and freshwater sediments can provide a wealth of information relating to the ecological impact of industrial and domestic development. In con­ trast to samples of water and biota, the sediments can i UNIVERSITY OF IBADAN LIBRARY * 143 be considered to be reflective of local environmental conditions over a finite period of time. Aquatic sediments are the main final accumulation site of water-borne constituents derived from natural (living organisms and their detritus in-situ and surroundings) and artificial (domestic, urban-industrial and agricultural wastes) sources. The aquatic sediments can provide not only a historic record of sedimentary environments, but also reserve the features of average sedimentary environmental conditions. Besides they are vice versa, also #possible sources of chemical con- stituents in wate* rs 13? / 2.3 SAMPLE COLLECTION AND FREQUENCY OF SAMPLING ' The purpose of sampling is to obtain reliable results through a carefully obtained representative sample.' A good analysis takes its root from a truly representative sample. Sampling may be discrete or continuous when dealing with .water samples. It is discrete sampling when a known amount of sample is withdrawn at a time • but it is continuous when water ̂ sample is pumped UNIVERSITY OF IBADAN LIBRARY ' 144 continuously through pre-combusted filters. This normally involves a large quantity of \vater of about 200 litres. -- There has been some advantages advanced'for grab (discrete) samples. These include the fact that spot results can be obtained quickly, trends can be followed and multiple samples can be taken readily for different analyses. Composite samples obtained by bulking grab samples are prone to gross errors due to excessive handling of the samples. A composite result can only be obtained by taking an average of the grab sample results. The frequency of sampling may be daily or weekly i or can even be monthly, depending on the time * available, transport facilities, site requirements and .nature of the samples. A/ter sample collection, the sample information tag should contain the information such as the time and place of sampling. The depth of sampling must also be chosen with care. In order to avoid change of concentration and the pH which may change during sunny d/ ays, it is preferable ✓t o s\ample in the first UNIVERSITY OF IBADAN LIBRARY 145 half of the morning(138) However, sampling and sample pre-treatment depends on the nature of sample, type of parameter required and the purpose of analysis. Sampling stations on rivers should be located along the axis of flow of the rivers. 2.3.i SAMPLE CONTAINERS Contamination of the sample may come from the container, therefore a great care needs to be taken when preparing the container for sample collection. For oil in water analyses, glass bottles are pre­ ferred with glass stoppers. Plastic paps are to be avoided because of contamination of the samples by plastic. Cap liner should be avoided, and cork stoppers should not be used (to prevent adsorption of oil) . The cleaning procedure often employed ( 1 3 9 ) involves washing of the glass container with soap and water, followed by acid washing with concentrated H2SC>4 for 5 minutes. The bottles can then be properly rinsed with distilled water and UNIVERSITY OF IBADAN LIBRARY 146 hydrocarbon-free water (.obtained by redistilling distilled water over KMnO^-KOH and pumped through a 91 cm by 2.5 cm preparative scale chromatographic column packed with XAD-2 resin). This is finally rinsed with singly distilled methanol and doubly distilled n-pentane The aluminium bottle cap liners to be used must be properly cleaned with acetone. In the case of sea water, degreased tin foil is used in place of aluminium foil to avoid sea water corrosion of the aluminium foil. Sediment samples can be taken in clean aluminium can or clean glass bottles or wrapped in aluminium foil. 2.4 SAMPLING AND SAMPLE PRESERVATION 2.4.1 SAMPLING Water samplers of different shapes, sizes and materials for collecting samples for hydrocarbon analysis have been reported in literature. Levy*'^^ used a Niskin Sampler for collecting seawater UNIVERSITY OF IBADAN LIBRARY > 147 samples in the determination of conjugated poly­ alkanes and aromatic hydrocarbons by UV fluorescence spectrometry. These samplers were developed by Niskin and consists of a series of ten or more "x bottles arranged around a central axle. The lids of these bottles are closed by means of a rubber string or teflon coated metal spring inside the sampler. Niskin samplers are available up to 30 dm3 , but samplers with volumes more than 1.7 dm 3 have restricted openings with respect to their diameter, and are therefore not encouraged. j A simple and reliable equipment for collecting surface water samples for hydrocarbon analysis was designed by Zso, lnay1 41 /J This device consists,c o [q u — CYLINDRICAL CAR BOY G L A 5 S THERMOMETER C U 9- fO OUT LET F I G ' - U VERT IC AL WATER SAMPLER UNIVERSITY OF IBADAN LIBRARY 150 ' C/UboY . G\Z.ASS FI G. 1 5 . H OR IZONTAL WATER SAMPLER \ ► f UNIVERSITY OF IBADAN LIBRARY 151 2.4.2 IN-SITU SAMPLING SYSTEMS FOR WATER In this system, hydrocarbons are extracted from water at depth by adsorption on a suitable material (e.g. polyurethane This system gives x greater flexibility in the volume of water sampled since the volume of water extracted is not limited to the sampler capacity as is the case with the ordinary devices mentioned earlier, rather, the volume of water extracted is a function of the rate at which water is pumped through the column of adsorbent material. In-situ sampling also makes it possible to collect large volumes desirable for detailed chemical characterization, particularly of open ocean water with only trace levels of hydrocarbons. i •> The equipments required for in-situ sampling are also smaller than conventional large volume- sampler^ since water is extracted at depth rather than collected. This limited size eliminates the need for special ship preparations ana makes the equipment easier to handle. In-situ sampling system also offers a high degree of contamination control. All immediate sources of UNIVERSITY OF IBADAN LIBRARY 152 1 -_-t- nation, including collection vessels, vessels, and solvents have been eliminated. However, the efficiency of this technique is limited by the affinity of the adsorbent material for individual hydrocarbon fraction. 2.4.3 PROBLEMS OF SAMPLING FOR WATER The inhomogenous nature of the oil-water suspen­ sion makes it difficult to obtain representative samples. It is also difficult to obtain a sample that is truly representative of the conditions that exist at any given depth because oil particles are not uniformly distributed with respect to either their size or population density throughout the water column. There is also the problem of determining the depths from which water samples should be obtained. However, most samples collected have been taken either from the surface, i.e. surface film samples or at 1 m d e p t h . D e e p e r samples may be collected depending on the type of sampling equipment available. f UNIVERSITY OF IBADAN LIBRARY 153 2.4.4 SAMPLING FOR SEDIMENT Samples may be taken from shallow water areas by d ivers. The top sediment layer is scrapped into glass jars which are then closed under water to avoid contamination while retrieving. Samples may be collected from boats-or ships; with dredge type instruments or grab samplers. Dredges are simple devices or apparatus for bringing up nud Csediment] oysters, specimens etc. from the bed of the sea, while grab samplers are mechanical devices / for holding up or obtaining materials-or objects. These are often used for obtaining surface samples and when deeper samples are required, dredges may be used. i Sediment covers are more sophisticated mechanical * devices which allow- sampling for horizontal layers of sediment. Grab samplers include the Van Veen grab!44>145 (fig. 16). This consists of a pair of jaws of galva­ nised iron plates fitted with a metal band to ensure that the jaws fit correctly. The places are attached by means of a strong chain to a mechanical device which permits opening and closing of the jsws. UNIVERSITY OF IBADAN LIBRARY 154 I UNIVERSITY OF IBADAN LIBRARY 155 Sediments are trapped between the two jaws. Other grap samplers include the Ekman grab, Shipek and Orange peel grab. Sediment samples can be collected with a pre­ cleaned Van Veen grab, scrapping the top 3-5cm off using a pre-cleaned scrapping knife and stored in aluminium foil enclosed in polythene bags or bottles. 2.4.5 PRESERVATION Unless the samples can be analysed on the same day, it may be necessary to add preservatives to prevent degradation of the parameter to be measured. The preservative used will depend on storage time and the particular parameter of interest, but for oil in water samples, acidification to prevent biodegrada­ tion is recommended. Acids commonly used include H7S0^ and HC1 14o . About 5ml of the acid to a litre of water sample to bring the pH to 2 if recommended 1^7,148)^ Chloroform and tetrachloromethane can as well be used. These two solvents (5 ml per litre of sample), can concen­ trate the oil and prevent microbial degradation. UNIVERSITY OF IBADAN LIBRARY Mercuric chloride-*^ (1.5mg saturated solution per litre) has also been used and if possible the sample may be stored at 4°C prior to analysis in the laboratory. Sediment samples can be preserved in a deep freezer (-20°C) or in dry ice during field trips and transportation. Long term storage is usually carried out in a deep freezer maintained between -70°C and -80°C (150). This very low temperature is used to eliminate changes due to biological processes which cart occur at "household" freezer storage temperatures. Sediment samples can also be preserved by freeze-drying whereby the water content is eliminated. 2.5 EXTRACTION OF SAMPLES After collecting the samples, a suitable analyti­ cal method must be chosen for the analysis of the samples for the different hydrocarbon components present. Most techniques require the prior extraction of the hydrocarbons from the samples into an organic solvent. Extraction of hydrocarbons from all marine UNIVERSITY OF IBADAN LIBRARY 157 samples has involved the same basic procedure. 2.5.1 EXTRACTION OF WATER SAMPLES In water, sample may be extracted for total oil (i.e. both dissolved and adsorbed oil) or the sample may be filtered and analysis carried out on both the dissolved oil in water and the adsorbed oil on particulate matter separately. Extraction of hydrocarbon materials from aqueous system usually involves the use of liquid-liquid extraction method, since it is the simplest and most direct method. It also lias the advantage that blanks can easily be prepared. Single or mixed solvents are used as extractants. Different organic solvents are used for the extraction of hydrocarbons. Each of them has its own merit and demerit, and also with different levels of efficiency. While some are safe to handle e.g. methanol, hexane, methylene chloride and freon 113 (trichloro trifluoro ethane (TCF) . Others are toxic e.g. tetrachloromethane, chloroform and benzene UNIVERSITY OF IBADAN LIBRARY 158 Some of the organic solvents that are commonly used include hexane, tetrachloromethane, methylene chloride, freon 113, chloroform, diethylether methanol, benzene and toluene (151 ’152) 2.5.2 DETERMINATION OF VOLATILE HYDROCARBONS IN WATER The methods for determining volatile hydro­ carbons in water differ from those used for analysing the high molecular weight fractions, mainly in the extraction technique. In headspace sampling, dissolved hydrocarbons are stripped from solution by purging with a suitable carrier material. Inert gases and purified air are suitable materials for the stripping procedure. Purified hydrogen may also be used. The type of stripping material used and the carrier gas flow rate chosen for a particular assay have to be optimised. Stripping of hydrocarbons from water can be carried out at room temperatures or at elevated temperatures say 70°C and above, but usually between 70°-90°C. UNIVERSITY OF IBADAN LIBRARY Is9 May et.al. ' used purified nitrogen gas as stripping material at 150 ml/min. for two hours, followed by another period of two hours at 70°C, using the same flow rate. The first stripping was done at room temperature. The stripping time used depends on the volume of liquid sample and the carrier gas flow rate. It is also a function of the hydrocarbon boiling range to be extracted. Swinnerton and Linnenbon used purified Helium gas at 50 ml/min. to extract -Ĉ hydrocarbons. The stripping procedure was carried out for only 15-20 minutes,because of the narrow hydrocarbon range extracted. After the stripping procedure, the hydrocarbon rich gas is passed through an adsorbent material on which the hydrocarbons are trapped. Activated carbon is the most widely used adsorbent and has a number of advantages over most materials. It is chemically stable and does not release substances that would result in contamination. Activated carbon is also thermally stable, thereby permitting desorption of adsorbed materials by heat. However, heat UNIVERSITY OF IBADAN LIBRARY 160 desorption is not encouraged as it may lead to loss of volatile fractions. Generally, adsorbent materials should have good pure characteristics such as a high surface area. They should be chemically stable and should not release materials which could lead to contamination. Their affinity for hydrocarbons should not be so high that desorption becomes only partially completed. 2.5.3 COUPLED COLUMN LIQUID CHROMATOGRAPHY This is a method developed for the determination of both the low molecular weight (volatile) and the high molecular weight (non-volatile) hydrocarbons in water samples with minimum loss of the volatile fraction. It is possible to analyse a given water sample for both volatile and non-volatile hydrocarbons by dynamic headspace sampling followed by coupled column liquid chromatography. After headspace sampling of the liquid sample, the volatile hydorcarbons are trapped on an adsorbent material while the sampled liquid is extracted by pumping through a chromatographic pre-column. A UNIVERSITY OF IBADAN LIBRARY 161 stainless steel column (6.5 x 0.6 cm) packed with a 37-50 unipel1icul ar (superficially porous) support with bonded g stationary phase was used by May et. al. (fig. 17). The pre-column is attached to a liquid chroma­ tograph capable of gradient elution, so that the effluents from the pre-column passes to the analytical column. The liquid chromatographic column used here is made of stainless steel (30 x 0.6 cm) and packed with a 10 /am micro-particulate (totally porous) support also with a bonded g stationary phase (ft Bondapak r >,'(155) l18j t Elution of adsorbed hydrocarbons from the analytical volume is carried out with 30:70 (v/v) methanol-water mixture at 3 ml/min. with the gradient programmed to increase the percentage of methanol in the mobile phase to 10090 in 40 minutes. The effluent from the analytical column is then analysed as appropriate (e.g. by UV, fluorescence, or MS). The main advantage this technique lias is that liquid-liquid extraction of hydrocarbons from the sampled liquid is avoided. This minimises the UNIVERSITY OF IBADAN LIBRARY 1’62 Fig. 17: Flow diagram for coupled liquid column chromatographic analysis (130) ) UNIVERSITY OF IBADAN LIBRARY 163 possibility of contamination from impure solvents. The technique also affords minimal sample handling thus reducing sources of error. 2.5.4 SOLVENT EXTRACTION OF PARTICULATE MATTER Water samples can be extracted unfiltered for total hydrocarbons or the particulate matter collected on glass fibre filters can be extracted for the adsorbed hydrocarbons. Because of the non-uniform distribution of particulate matter and the low solubi­ lity of hydrocarbons, the amount of hydrocarbons pre­ sent in the particulate matter (i.e. undissolved) may be a guide as to the level of hydrocarbon contamination. It has been shown ( ^ 6) t l̂at fulvic and humic acids can fix and retain hydrocarbons by either incorporation into a molecular sieve-type structure or hydrophobic adsorption onto the surface of these humic materials. It has also been reported reported^^^ that up to 50% of the organic material in sewage effluents may play a major role in the transport and deposition of hydrocarbons UNIVERSITY OF IBADAN LIBRARY 164 introduced by waste water effluents into estuaries and coastal waters. For these reasons, particulate matter are collected on pre-combusted Gelman type A/E glass fibre filters held in millipore stainless steel filter holders and stored at -20°C in pre-cleaned mason jars with teflon linen caps and dried before extrac- The filter can be extracted in soxhlet extractor with hexane for 4 hours and then with chloroform for 4 hours more. The extracts are combined and the solvent removed^^^. Blanks can also be evaluated by extracting unused filters and subjecting them to the same analytical scheme. For total hydrocarbons, sample volume of between 500ml and 1 litre are usually collected. The sample may be extracted immediately after collection (i.e. on board) or about 10 ml of hexane may be added to the sample in the bottle (the organic components will be concentrated in the hexane layer) and stored on board at -5°C. UNIVERSITY OF IBADAN LIBRARY 165 2.5.5 SOLVENT EXTRACTION OF WATER Different solvents have been used individually or in admixture for extraction of petroleum hydro­ carbons in water. The commonly used solvents are pentane, hexane, benzene, tetrachloromethane, trichlorotrifluoroethane and methylene chloride. Extraction of oil from water with hexane was carried out by Burns and Villene.dve ̂ using a sample-solvent ratio of about 50:1. Two or three extractions were carried out on'each sample (500 ml). It was reported that about 80?0 recovery can be obtained for total hydrocarbon with hexane as extractant. At the end of the extraction exercise the com­ bined hexane extract can be freed from the residual water by running the extract through a funnel containing anhydrous sodium sulphate on glass wool. What is collected here is then evaporated at 50°C with nitrogen gas, on a thermostically controlled water bath. „b eari. ng, J_. (162) extracted water and sediment samples with hexane and concluded that fresh UNIVERSITY OF IBADAN LIBRARY 166 Jrocarbons may be extracted much more efficiently hexane while not efficiently extracting weathered zr indigenous hydrocarbons. This discrimination co ild be of practical importance when che interest is -ainly on recently added hydrocarbons. Extraction of water sample with tetrachloro- nethane (CCl^) can be performed in two ways, namely, liquid-liquid extraction of water sample with CCl^ and polyurethane foam adsorption followed by soxhlet extraction with CCl^. Both methods are oil pre­ concentration techniques. In the liquid-liquid extraction technique about one litre of water sample is required for the extraction. The extraction is carried out in a two-litre separatory funnel with 30 ml CCl^ added for each extrac­ t i o n ^ ^ ’ ̂. The separatory funnel with its contents is subjected tu 30 seconds agitation and 3 minutes settling period, the non-aqueous phase is then drained through a funnel containing about 30g of anhydrous sodium sulphate over a glass wool plug and collected in a 100 ml volumetric flask. The extraction step is UNIVERSITY OF IBADAN LIBRARY 167 then repeated twice more. The sodium sulphate is rinsed with 5 ml of CC1 and added to the extracts. The polyurethane foam adsorption method required polyurethane discs for the collection of samples^^5) ̂ About 1-5 litres of water is passed through the foam in a stainless steel holder and then the retained oil is extracted in a soxhlet apparatus with CCl^. There is need for new foam disc to be cleaned before use by Soxhlet extraction with CCl^ for 4-6 hours in order to reduce blank values to acceptable levels. It has been shown that recoveries of oil were greater than 85?0 for those concentration above 5 mg per litre. Gruenfeld (-*-66) has WOrked on dispersed oil in water using trichlorotrif1uoroethane (TCF) as an extraction solvent. This solvent is particularly recommended for extracting dispersed oils from water, because it is virtually as efficient for these extractions and as usable for the Infrared (IR) determinations of oil as CCl^. It is especially preferable to CC1^ in situations where adequate UNIVERSITY OF IBADAN LIBRARY 168 ventilation may be lacking, such as in some mobile laboratory and field use. The recommended procedure for extracting dis­ persed oil from water is the addition of 5 ml of 501 \ H 2SO4 and 5g of NaCl to 1 litre samples. Extraction is carried out with four 25 ml portion oi; TCF in,.:2- litre separatory funnels. The acidity is checked (pH<3) prior to solvent extraction and completeness of extraction should be evaluated. Sea-water can be analysed without addition of NaCl. The TCF layer from the separatory funnel is drained through a funnel containing solvent-moistened filter paper into a clean tared distilling flask. If / a clear solvent layer cannot be obtained, lg pf t Na2^0 ̂ is added to the filter paper cone and slowly drain the emulsified solvent onto the crystals. The extraction procedure is repeated twice more, and the combined extracts is transferred to the tared distill ing flask and the filter washed with an additional 10 to 20 ml TCF. The TCF is evaporated under nitrogen. The residue is cooled in a desiccator for exactly 30 minutes and weighed. This can then be UNIVERSITY OF IBADAN LIBRARY ■ 169 cleaned up for the hydrocarbon determination. Kennicutt and Jeffrey ̂ 4̂ -- ' used chloroform t to extract water sample initially sterilized by the addition of chloroform (5 ml per litre of sample and 3-5 ml of concentrated HC1 to maintain pH at 2). A sample to solvent ratio of 70:1 was used for each extraction. Direct extraction of water with dichloromethane for total hydrocarbons was carried out by Barrington et. al_.(168). ̂ Table 16 below compares the concentrations of filterable (particulates] and filter-passing oil and unfiltered samples. - t Concentrations of filterable and filter-passing / oil compared to concentrations obtained if water is C. « ' unfiltered.. All concentrations (pg/lOOml] were obtained by fluorescence spectroscopy. The difference of the peans was not significant at 951 level when estimated with a t-test. The summary of some analytical methods for deter­ mining petroleum hydrocarbons in water is set out in Table 17 below. C. I UNIVERSITY OF IBADAN LIBRARY 170 TABLE 16: RELATIVE CONCENTRATIONS OF OIL IN FILTERABLE, FILTER-PASSING AND UNFILTERED"SAMPLES (BY FLUORESCENCE SPECTROMETRY)(lbUfrg/ 100 ml. Sample Filterable(Particulates) Filter Passing A+B Unfiltered (A) (B) 1 22.2 4.8 27.0 23.9 2 14.8 4.7 19.5 24.2 3 19.2 5.2 24.4 23.2 4 15.8 4.5 20.3 22.8 5 16.4 4.2 20.6 22.5 6 11.8 3.6 15.4 18.0 7 11.8 3.3 15.1 18.3 8 11.8 4.1 15.9 18.0 9 13.8 4.5 18.3 14.1 10 12.2 3.7 15.9 17.3 Mean 19.2 20.2 UNIVERSITY OF IBADAN LIBRARY 171 TAHI.K I 7 I ANALYTIf'AI. TECHNIQUES EOH TIIK lllin-HMINATION OF IIVIlRflCARBOWS IN IM'IEK (11>I Technique Component: flamplt* Da terra Iliad 3l*s (g) Advantages Equipme Disadvantage* proxima ntet C(oAspt­ • Analysis Time ' In Dollarn) ,. (OEplearpasteodr) References Cj-Cjq Hydrocarbons \\ Cat equilibration Individual hydrocarbon* 50-250ml Port's per trillion sensl- Analyalft time relatively and hydrocarbon type ctalrvblotyn,s dferpoumr antoensh yhdyrdor- o­ long Css( 1c3h,0r0o0m)atographs 10(0-.V\) -2m inh) Me Aulifie, 1969, 19 pcarrebpoanrsa.t ionNo sample I Cat stripping 1 • . Inadnidv idliuyadlr ol̂cayrdbroonc atrybposna 1-2 liters Mofe aCs,u,r e Cb,a,cCk,g ro, unC,d, lCe,v el,s Nonhydrocarbons can Can chromatograph 10-30 min interfere. Analysis time (15,000) Swinnerton and Linnerbon, (0.5-1 h) 19b 7 1.-, n-Ĉ In open ocean relatively long' waters Vacuum degassing Individual hydrocarbons 4-20 liters As above, can be used to Normally used to. measure and hydrocarbon type continuously measure 3»30 min Cj-Ĉ in sea-water. .Complete systera- Schink et al., 1971 hydrocarbons in water Kqutpment expensive gpruampohs , (g3a0s0 ,0c0h0r;oma- (3-30 min) Fort et al., 1973 2.500 per day rental) Ĉ j plus Hydrocarbon! Gravimetric Nonvolatile extractahles 1-4 liters Simple minimi n> Nobnedtiwaegenno stic, c'onequipment 0,3-1,000 c. Gl(a1s,s0w0a0)re, balance 20 min Environmental Projection mg/liter (40 min) Agency, 19 UV absorption Conjugated polyalkenes, 1 liter Useful for cone. spectrometry aromatics * 10 g/litef Noste nvseirtyi vedi atghnaons tfilcu,o relses­s UtV 5,r0o ab 0m0e stoerrp t(i3o,n0 s) 00- p ec­ 20 min Levy, 1971 cence spectrometry. No (20 min)information on saturated HC* UV flucrescene* Unsaturated compounds, 1 liter Useful for cone. Not very diagnostic. No Fluorescence spectro- 20 min Levy, 19 71; Thur- nut’ spectrometry aromatic * 10 g/llter; measure HCs information on saturated trometer (10,000) (20 min) Knight, 19 •in open ocean . ’ators HCs. Fluorescence may be quenched. Zitko. and Carso-1.970 Infrared Methyl, methylene, 1-4 liters spectrometry’ carbonyl, aromatic Information on functional groups. Identify conta­ Concervtra lions 3 g/liter, 0.1 mg. Not very diagnostic Low or high resolution 5-10 min Brown et al. 19 Total hydrocarbons minants such as silicones, I(n3fplasticizers ,5 r0a0r-e3d5 ,s0p0e0c)trometers t a(f2t0e-r4 0 smeipna ra­ Kawahara, 196 ti Simard et al.watoenr )from Gas chromatography Hydrocarbon profiles 1-20 liters (low resolution) Quick examination, reasona- and boiling range of bly"diagnostic Lhiitgthlley wienaftohremraetdi ono f from Ga(s1 0c,h0r0o0-m1a5t,o0g0r0a)phy 10 min (3 h) BArdolard esample, C^-C biodegraded oils wn et t ala,l.. D1®uckworth,! jq Ehrhardt and 1972 Caa chromatography More detailed hydrocar- 1-20 liters Better diagnostic power. Little information from Gaq chromatograph 10 min Krelder, 1971; 1973; Ramsd (high resolution), special detectors bporno fiplreosf,i leisn.d iviSduulaflu r Sinu lfiudre nctoimfpiocuantdison assist hbiigohdleygr awdeeadt heoirlesd or (15,000-20,000) <2 h) Wilkinson, 19 2'afiriou hydrocarbon ratios, et al CU"CM> i: Mass spectrometry Hydrocarbon types 1-10 liters Prtoyvpied eisn'f coormmpalteitoen HC Ceqoumipplmeexn t?and expensive Low resolution, mass 10 min Aczel et al. 19 computer .i nRteeqrufiarcees Hsipgehc trroemsoeltuetri o(n6.0 ,000). (2 h) HHoaosdtin(80,000-150,000) a gnsd 0et a1l9 59; Robin 1971 _ Camaa ssc hrSopmeacttorgormaepthe,r Specific hydrocarbon, 1-10 liters Iidnedinvtiidfuya la ndh ydmreoacsaurrbe ons pVeenrsyi vceo mpeqlueisp mdenndt ex­ Acodsdt gatso acbhorvoematograph '2-4 h V S o (2-4 h) (11) UH i ydrocarbKons are extracted from water and then separated from nonhydrocarbons by #col\pnn or thin layer chromatography. • • / UNIVERSITY OF IBADAN LIBRARY • 172 2.5.6 COMMENTS ON THE SOLVENT EXTRACTION OF WATER SAMPLES As earlier stated, extraction step is a major factor in obtaining a reliable result. The pollutant to be determined must be isolated from other materials which can serve as contaminants. In the choice of solvents for extraction process tetrachloromethane(CCl^) is very efficient but toxic^ \. . ■ Methylene chloride or trichloro'- trifluoroethane can be used to provide the same level of efficiency. . In the choice of methylene chloride as a substitute for CCl^, the factors in its favour are its lower toxicity and lower boiling point (40.1°C compared"to 76.8°C). A comparison of the two solvents t * indicates that using CCl^ causes about half the fluorescencing material in seawater [both raw and spiked with fresh crude oil) to be lost, most probably during the evaporation step (Table IS). In the case of trichlorotrifluoroethane, it is also -safer than CCl^. They have been found to be about equally effective for extracting the dispersed oils from water. Virtually the same number of extractions f UNIVERSITY OF IBADAN LIBRARY TABLE 18 COMPARISON OP MliTI1YLENE CHLORIDE (CD ,C 1 /) AND TETRA- CliLOROMETi lANE (CGI.) AS SOLVPNTS FOR EXTRACTING PPTROLPUM RESIDUES FROM SPA WATER COLLECTED ALONG THE HALIFAX- BERMUDA SECTION. USING T-TLST FOR LAIRED VARIABLES-THE' DIFFERENCE WAS SIGNIFICANf AT THE 9S°o LL\T;L. EQUIVALENT mg OIE/EITER Ql2 CI2 EXTRACT CCLj EXTRACT 8.0 0.6 2. 5 0.5 0.3 3.4 1.9 0.2 3.6 1.3 1.8 0.0 6.1 0.2 0.9 0.6 1.5 1.1 1.3 0.2 4.3 1.7 1.4 0.5 2.0 0.7 0.7 0.8 1.5 0. 6 2.5 0.1 0.0 0.4 0.0 0.0 x 2. 56 0.72 UNIVERSITY OF IBADAN LIBRARY 174 with each solvent effected removal of the oils. In addition TCF has the following advantages over other solvents. (1) It is non-polar and is not a hydrocarbon. (2) It is heavier than water, which enables it to be removed simply with a pipette from the bottom of the extracting vessels. (3) It boils at 47.6°C enabling it to be concentrated » quite readily. (4) It is transparent to UV light at 254 nm. It has also been found out that while non- chlorinated solvents such as hexane and pentane are excellent for extracting petroleum hydrocarbons from water, having a specific gravity of less than one, they are difficult to recover from large volumes of seawater (2 litres) under difficult field conditions. 2..S. 7 EXTRACTION OF SEDIMENT In the techniques applied to sediments, the extraction step varied from a simple elution with petroleum ether of a column containing the dry sample to the long Soxhlet UNIVERSITY OF IBADAN LIBRARY 175 extraction with methanol (1/2’1 73) . Digestion method with methanolic potassium hydroxide has also been used. Sediments can be extracted wet or dry. Extraction of hydrocarbons from sediments usually iequires more vigorous techniques than water sample because the hydrocarbons are incorporated into the sediment matrix. In the analysis carried out by Oudot et. al. , frozen samples which were thawed and dried at 60°C for 48 hours were used. The extraction step involved chloroform as solvent, and the sample was extracted for 10 hours in a Soxhlet apparatus. In some samples, internal standards (l/4g g 1 dry weight n-eicosene and 1 jr g g-1 dry weight phenanthrene) were added prior to extraction extraction^ . The total lipid extract . ^ obtained was dehydrated and purified by percolating through Na2S0 ̂ over florisil (magnesium trisilicate, 60-100 mesh) column. Lake et. al■ . (176) had worked on sediment for the determination of petroleum hydro­ carbon level. The sediment sample analysis involved UNIVERSITY OF IBADAN LIBRARY 176 drying the sample at 105°C in an oven and grinding the sample in a mortar. The organic matter content was determined in a sample aliquot as ash free dry weight at 550°C and is expressed as a percentage of dry -eight. The ’oil and grease' content was determined by extracting dried C105°C) pulverized sediment with petroleum ether Ch.p. 40°C) in a Soxhlet apparatus for 2 hours. After drying the extract at 105°C, then it is cooled and weighed to a constant weight. This is called the -extractable amount, considering that pig- • ments and other natural organic compounds are also included. Giger and Blumer (138) Blaylock, Bean and Wildding 173 extracted partially thawed sediment' L * sub-sample in pre-combusted glass Soxhlet thimbles for 18 hours with 250 ml of methanol/benzene (2:3 v/v). After cooling, the extract was washed with IN HC1 saturated with NaCl and the benzene layer was separated. The aqueous layer was separated twice with 75 ml of pentane and the combined benzene and pentane extracts were washed again with the acidic saturated salt solution. The organic layer was separated and dried UNIVERSITY OF IBADAN LIBRARY 177 over anhydrous Na2 SC>4 overnight. Activated copper was used to remove sulphur. Some of the other methods tried by different chemists are displayed in Table 19 and the comparative results of the extraction efficiency with internal standard were found to vary from about 301 (Shaw method) to almost 100Z (Blaylock method). However, from the variety of analytical methods, apparently no standard method of analysis has been selected for particular types of marine sediment sample. Instead, interlaboratory calibration studies have been reported. Results of such studies indicated that the analysis of marine sediments poses many difficulties. Concetnration values for a given sedi­ ment sample may vary by a factor of 30 for "polluted" samples and by a factor as great as 135 for trace levels (ug kg"l) of hydrocarbon in sediments. The difficulty of preparing homogeneous sediment samples is often stated as one of the reasons UNIVERSITY OF IBADAN LIBRARY 178 TABLE Ij9 ANALYTICAL TECHNIQUES FOR THE DETERMINATION OF HYDROCARBONS IN SEDIMENT EXTRACTION TECHNIQUE PURIFICATION TECHNIQUE COMPONENT AUTHOR APPLICATION SAMPLE NATOURE EQUIPMENT USED SOLVENT SYSTEM COLUMN FORM ELUTION DETERMINED SEDIMENTS Dry at 80 C 1 x 10 cm column Petroleum ether - - Total Hydrocarbons(THC) 171 SEDIMENTS Wet Soxhlet MEOH, n-pentane Sj09/Al203 k bed volume of Total Hydrocarbon 3/2 (v/v) n-Pentane (THC) 53 SEDIMENTS Wet Soxhlet MEOH, n-hexane — Petroleum like fraction in the 172 lipids SEDIMENTS Freeze-dried Soxhlet MEOH,, benzene 1llOO gxg s30ioc2m2,3/ 70ml n-pentane, HC in two n-pentane a i o 100ml benzene fractions: 173saturate and aromatic SEDIMENTS Wet Grinding with n-hexane 3 x 15 cm 1.5 bed volume THC ashed MgSO^ Si02 of n-hexane 179 and ashed grinding sand SEDIMENTS Wet waring blender c h c i3,m e o h, 1x35 cm 100ml n-pentane HC in two fract­ 15g Si02 50 ml 25% ben­ ions: aliphatic 180 n-pentane. zene in pentane and aromatic SEDIMENTS Wet Shaker n-pentane Si02/Al203 4 bed volume THC 3/2 (v/v) of n-pentane 182 UNIVERSITY OF IBADAN LIBRARY 179 for poor agreement of results between participating laboratories, but this was shown*in the study carried out by Wong and Williams (188) as unlikely to be the prime cause of such large variatio/n 1s O. Q \ In the work of Wong and Williams ' , three extrac­ tion procedures were studied namely (Table 20): (1J Digestion by methanolic KOH and further extraction with methanol (2) Soxhlet extraction with chloroform (132) and and (3) Soxhlet extraction with tetrachloro- methane'189-190). The results obtained were also given ir Table 20 below. The sediment sample used was thoroughly mixed in order to get a homogeneous sample, which was divided into two portions. One portion, designated wet sediment, was stored in a freezer at a temperature main- tained at 0 C. The other portion, designated the dried sediment, was transferred to aluminium foil and dried in an oven at 45°C for two days. The dried UNIVERSITY OF IBADAN LIBRARY TABLE 20: COMPARISON OF EXTRACTION METHODS FOR HYDROCARBONS IN.MARINE SEDIMENTS Procedure SampleNature Extraction Technique Purification Technique Results '’I Column Form Elution • 1. Methanolic- Wet Digestion of sediment sample with 50ml metha- 1.5x20cm 10ml of 20% 1. For wet sediment sample; mean value KOH diges­ nolic IN KOH for 24 hours. Followed by 1cm AI2O3 (V/V) benzene obtained for total organic extract tion and soxhlet extractiwith methanol for 24 hours. (120 mesh) in pentane 30ml (TOE) i.e. pre-column purification extraction. The combine extract was extracted 4 times of pentane. = 7714±342 ugg-1 dry weight, value * with a total of 200ml of 5% (V/V) benzene in obtained for post column purifica­pentane after the addition,of 5ml of dis­ X tion “ 634* 9*508.tilled water. ‘ i The organic extract was driect with 10cm SiO? sodium sulphate overnight and then evaporated (lOOmeshT to 1ml in rotary evaporator at 30°C. The \5% deactiva­ solution was finally evaporated to dryness in tion. \ a vial under pure nitrogen gas. The residues redissolved in 2ml of n-pentane. Or.e ml of \ . . ' the solution was transferred to a column for i purification. The other portion was used to determine the total organic extract, before \ column purification. Dry 5ml of distilled water-was added to the . 2. Dried sediment': 102-6271+265; post mpthanolic-KOH solution to prevent trans­ column purification * 5330+183. • esterification. All- other steps were as given above. Extract 1 Extract 2 2. Soxhlet Both Extraction with 150ml of chloroform in As above As above Wet Extraction • wet soxhlet extractor. After 24 hours, 75ml of sedi­ Pre- Post- Pre- Post- with and the CHCI3 was withdrawn and replaced with ment. co-lumn column coluran column Chloroform' dry . 75ml fresh solvent. The operation was V 6154± 3739± v * 1856± 992± repeated after another 24 hours extraction. 2971 1470 1339 1011 Total extraction time was 72 hours with a total of 380ml solvent * Extract 1. The sample was extracted for further 72 hours Dried 8226* 4904± 205 86 • with 300ml of fresh solvent following the 381 303 same procedure as described above = Extract II. 3..Soxhlet Wet As above in procedure 2 with CCl^ as solvent. As -above • As above Wet 4604* 2188* 2316* 1041± extraction and sedi­ 1462 869 1175 628 with tetra- dry ment.. chloro methane. Dried 6358* ‘ 4438± 82 39 sedi­ 201 282 ' ment. • * / UNIVERSITY OF IBADAN LIBRARY ■ 181 sediment was ground to fine powder in a glass mortar, kept in a small reagent bot le and stored in a desiccator. Prior to analysis, the wet sediment was thai\red at room temperature for several hours, and the required amount of sediment taken out and'weigheaVr- About 8-10g of wet sediment or 3-4g of dried sediment were used for each determination. The water content of the wet sediment was taken as the loss in weight on drying at 105°C for 24h. /The extraction techniques and analyses were given in Table 20 . - The results *o xf” the 3 extraction procedures for • .r- dried sediment were comparable and with reasonable precision, although the hydrocarbon values (i.V. post-column values) obtained from•procedure 2 and 3 were_ si ightly'lower than that from procedure 1. A closer’ look at the results revealed that drying at 45°C resulted in the loss of the mofe volatile organic components of the sediment sample. Thus, the total hydrocarbon value of a dried sample is about 16i less than that of a wet sample, based on results from procedure 1. \ i UNIVERSITY OF IBADAN LIBRARY 182 For wet sediment, the precision of procedure 1 is fairly good. However, procedures 2 and 3 gave values that were much lower than that of procedure 1. Furthermore, replicate determinations gave greater x variability. Reasons advanced for this are sample inhomogeneity and the effect of water in .the sediments with the latter being the major factor. Explanation: When fresh, the water in the sediment was probably well mixed and bound to the sediment \ sample matrix, and was not r/eadily absorbed by the extraction thimble. As a consequence, ’’wetting" of the sediment by the solvent is inhibited, thus reducing the contact of the sol/vent with the sediment. After storage of 0°C for several weeks and subsequent thawing, some of the water present was reported to have separated from the sample, presumably due to a freeze­ drying effect, followed by crystallization on the walls of the container during storage.- That the physical state of the water’ present did affect the extraction efficiency was borne out by comparing concentration figures of Extract I and Extract II for* procedures 2 and 3 (Table 20) . iThe extraction efficiency UNIVERSITY OF IBADAN LIBRARY 183 was lowest for fresh samples for both solvents, chloroform and tetrachloromethane Chloroform came out to be more efficient in extracting hydrocarbons than tetrachloromethane for wet sediment samples. In the case of dried samples, both gave values of hydrocarbons close to those found using procedure 1. Chloroform, being more polar than tetrachloromethane extracted more lipid * material from hoth the wet and dried sediment samples. Good recoveries were obtained for the three hydrocarbon compounds used. The results are given in Table 21. However, the good recovery merely showed that losses during operations for the three extraction procedures were minimal. It did not reflect the extraction efficiency of the procedures studied. An earlier attempt has been made by the National Bureau of Standard to compare results for individual hydrocarbons. Collaborating laborato­ ries (8) were asked to report identities and concen­ trations of the three most abundant aliphatic and UNIVERSITY OF IBADAN LIBRARY 184 TABLE 21 PERCENT. RECOVERY OF HYDROCARBONS ADDED TO SEDIMENT \ Method Nrou- nof C13 C22 Phenanthrene Extraction Procedure 1 (CH-jCH-KQH digestion 2. 94+6 95±4 91±8 and extraction) Extraction Procedure 2 //• (Soxhlet aiCl3 extraction) 2 92+5' 91±3 96±3 Extraction Procedure 3 83+12 92±2 94±1 ■1 Soxhlet CC14 extraction) ' , • --- L * , O' UNIVERSITY OF IBADAN LIBRARY 185 aromatic hydrocarbons, respectively. The intercali­ bration material consisted of two intertidal sediment samples from the Prince Wilxiam Sound and North eastern Gulf of Alaska, II.S.A. The sampling sites were Hinchinbrook Island; tuis site is at the ocean entrance to the Prince William Sound and is constantly being washed with water from the Gulf of Alaska. • Katalla River; this site is downstream from a known oil seep and provides samples with hydrocarbons known to be of petroleum origin. The analytical methods employed by each of the participating laboratories are summarized briefly in Table 22. The results of homogeneity studies by National » • t * r Bureau of Standards (NRS) utilizing the dynamic headspace sampling technique showed that the precision was better for the Katalla sediment than for the Hinchinbrook sediment. (Katalla 910 mg/kg _+ 25?0 n = 9 and Hinchinbrook 420 g/kg + 30% n = 12) . The average recovery of phenanthrene internal standard used for the two sediments was 83°a for Katalla and 41°a for Hinchinbrook. These results (recovery) were used to I UNIVERSITY OF IBADAN LIBRARY 196 TABLE 22: METHODS OF SEDIMENT ANALYSIS IN INTERLABORATORY CALIBRATION 187 N3S Gas Chromatography Lab Extraction Separation Column Standard (a) Dynamic headspace extraction 100 m SE-30 SCOT Aliphatic and aromatic of 100 g sediment in 500 mL 80°C for 4 min - 275° internal standard added pure H,0. Volatiles trapped at 4°/min. . prior to sample work-up on Tenax GC adsorbent. at start of analysis. Ob) Diethyl ether and methylene Liquid chromatography on Same as above 5 Squalene internal stan- chloride'Soxhlet extraction pBondapak NH2 to remove idard added- at start of of 100 g wet sediment. polar biogenic compounds analysis. 2 Diethyl ether extraction of 100 g. Column chromatography on 20-30 m SE-30 SCOT’ Hexamethylbenzene wet, acidified sediment on ball- activated silica gel. 60"C for 10 min - 2’50° standard added prior to mill tumbler for 18 h. Aliphatics eluted with at either 2 or 40/min. GC analysis petroleum ether. Aromatics eluted with methylene chlo­ ride in petroleum ether. I 3 300 g wet sediment dried by washing Column chromatography on 6 ft 4% FFAP on Gas External standard with methanol. Reflux extraction alumina:silica get (1:3). Chrom Z. containing several . with benezene-methanol (3:2) for aliphatic, aromatic, 14 h. Saponification with 0.5 N Aliphatics eluted’with hexane. 80°C - 225° at 4°/min. or and olefinic , KOH in methanol; extraction into Aromatics el’ned with benzene. 6 ft 3% SP 2100 on hydrocarbons benzene and taken to dryness. . Residue taken up in hexane. * Polar fraction eluted with Supelcoport \ metl\anol. 100°C - ?25° at 4-Aain.250 <7 wot eodlmont o x tia c te d w i th Organic extract, partitioned 3% O V -1 ^ E x te rn a l standardiiwillwtIn oil |a. nd ""b uIn-.xcnI ov i I mmtuituI m.no.l iiii n II i onm ilia mi i ty c lo - T0"C - '9 0 0 ° -«t Q V in ln . co n ta in in g jx jly n u c le a r mol h y I o n e oli I I do , Hudui o,1 haxane In give p o lycyclic aromatic hydrocarbon.axlrai led withh i llonmie mid fr a c tio n . Column climmnto-giapliy'lin hi I lli'ii gal) alulad UNIVERSITY OF IBADAN LIBRARY l r 1 OGa \ _TA_B_LE_ _22_ _(_co_n_td_.)_l____ ;__________________•_____________i ■ Lab Gas Chromatography NBS ‘ Extraction Separation Column Standard 1 5 ISO. g dried sediment extracted Column chromatography on A 20 ft 5% eutectic Spiked blanks: C18 and . they are : probably more specific than UV or fluorescence methods used without column chromatography . Theii main advantage over Gas Liquid Chromatography (GLCJ lies in the fact that they are simpler and more rapid for obtaining quantitative results. In a system to separate non-hydrocarbons from the hydrocarbons, a column with internal diameter of 1.8mm and 5cm long packed with 101 deactivated silica gel is used. n-nonadecane is used as the standard. The saturated hydrocarbons were all found to have a response between 76 to 110% of n-nonadecane. Unsaturation decreased the response per unit weight. This decrease was minor among the mono-unsaturated compounds, but quite strong among the poly-unsaturated alkenes such as carotene and squalene. Aromatic hydrocarbons will also be underestimated. Naphthalene, for example, has a response that is only o2n9a% of that of nonadj ecane (221 1 (222) , UNIVERSITY OF IBADAN LIBRARY 225 For the determination of the aromatic hydrocarbons, the same extracting and concentrating procedure is used as above. The apparatus is somewhat different in that a IJV detector, which measures absorbance at 254nm, replaces the flaw calorimeter. A longer column (10cm) with more active (2°i deactivated) silica gel is also used, since aromatic hydrocarbons are somewhat polar and more care must be taken to ensure their separation from other weakly polar compounds. The chief disadvantage in the use of a UV detector lies in the fact that the response per unit weight varies enormously from compound to compound.. As a result all values can only be given relative to a standaid and will vary greatly depending upon the standard selected. HPLC analysis has also been performed on a water associates ALC/GPC-502 liquid chromatograph with an FS-770 Schoeffel fluorometer.(223) A 30cm x 6mm OD, lO^porasil column, with a chloroform solvent flow rate of l.Oml/min. The data are analyzed with the help of a Hewlett-Packard 3380A integrator. The number of counts (area) of the oil peak in an UNIVERSITY OF IBADAN LIBRARY 226 unknown sample is compared to a graph prepared from injection of known amounts of oil. In all cases, a graph has to be prepared for each kind of oil. A series of tests was performed in which the Liquid Chromatography (LC) system and the fluorescence excitation and emission wavelengths were varied. An LC solvent system of chloroform and an excitation wavelength of 403nm with a kV 418 emission filter (418nm range) provided complete selectivity between petroleum hydrocarbons and biogenic hydrocarbons. From the outcome of the work performed to determine the effect of sample preparation on the results, it was discovered that the benzene eluate provided results that were more reproducible. The data obtained from biological samples also indicated that the benzene eluate gave the most reliable results. 2.8.4 GAS LIQUID CHROMATOGRAPHY (GLCj /’211-298 Gas liquid chromatography is a technique of separa tiun of mixtures in microgram quantities by passage of the vaporised sample in a gas stream through a column containing a stationary liquid on a stationary solid UNIVERSITY OF IBADAN LIBRARY 227 support. Components migrate at different rates due to difference in boiling points, solubilities or adsorption. In gas-liquid chromatography (GLC), the column contains a support material which is coated with a liquid stationary phase. This phase is so chosen that the components of the sample are soluble in the phase as well as in the carrier gas. Every compo­ nent has a characteristic solubility in the liquid and in the gas. Thus, a partition of each component takes place between the two media. As the carrier gas passes through the column during the entire analysis, the components are transported and eluted from the column by the gas. The components which are most soluble in the gas will be eluted first and those which are more soluble in the liquid will come later. On leaving the column, the components enter the detector (e.g. flame ionization detector, FID). The detector gives an electrical response for the components. The electrical output is amplified and fed to a strip chart recorder which delivers a conti­ nuous plot of detector response versus time. When all governing conditions are kept constant, the time from UNIVERSITY OF IB DAN LIBRARY 228 sample injection to rhe appearance of a component peak - the retention time - is constant too. Thus,, the retention time is used as a means of identifica­ tion of the components. The area under the peak is proportional to the amount of the eluted compound. By comparing the retention time and peak area of a compound in the sample with that of an injected standard of known concentration the level present in the sample can be estimated. Often peak heights instead of peak areas are used. Gas-liquid chromatograph with a flame ionisation detector is generally used as a quantitative method for investigating the major component composi­ tion of oils and for observing the presence of biogenic hydrocarbons in environmental samples. Column oven temperature programming enables samples to be analysed over a wide boiling range. Quantitative use has been made of this technique by measuring the concehtrations of n-alkanes ( 226 ) Or by integrating the total area of chromatograms* . The method is not, however, readily applicable to specific aromatic compounds as these tend UNIVERSITY OF IBADAN LIBRARY 229 to be lost, even when using capillary columns in the unresolved envelope or "hump" under the alkane peak .b asel. i- ne U99) Of all the techniques used for oil spill identi­ fication, gas chromatography has been the most widely exploited. A low-resolution packed column will give the boiling range of the spill and sometimes a tentative identification. A high-resolution column is capable of giving a large amount of information, which can be handled as a simple fingerprint or can be quantified by measuring the ratios of isoprenoid hydrocarbons (in particular pristane and phytane). Extra diagnostic power can be achieved by the use of selective detectors. In chromatographic analysis different column materials, packing and conditions are used in solving the problems posed by the wide range of petroleum hydrocarbons present in the marine environment - water, organisms and sediment. Column materials commonly used are stainless steel and glass of varying dimensions. The length depends on whether it is to be used as packed column UNIVERSITY OF IBADAN LIBRARY t 250 (1.5m long) or open tubular. The latter is always longer, and can be wall coated (WCOT) or support coated (SCOT). The major points to be considered un» der gas. chromatography relating to pollution* are: sample introduction, column selection and sample recovery. • *" ‘ * 2.8.4.1 SAMPLE INTRODUCTION Samples may be introduced conventionally in solu­ tion, by a column injection or by vaporization in a heated injection bloclc. Carbon disulphide, is a suita­ ble solvent. Some ’ special introduction techniques are' applicable to the pollution field.. The British Institute of Petroleum Standardization (IPS) commit-tee has described a modified inlet system that accepts a solvent free oil sample in a glass tube (212)^ -; ■ . The tube is inserted via two ball valves’ into the' heated injector. A similar but simpler technique involves the rapid insertion into the injector of tfie oil contained inside a short piece of glass tubing The injector is immediately clo.sed by septum and nut. The tube is left in the inVjector at a temperature and UNIVERSITY OF IBADAN LIBRARY 251 for a time that assures evaporation of hydrocarbons but minimizes thermal decomposition of the residue. The front end of the column is cooled with air or dry ice. Later, the glass tube containing the residue is withdrawn and the temperature programme -is started. In this way the injection port remains clean. The technique is highly tolerant of the presence of high boiling materials e.g. asphaltenes, lipids. 2.8.4.2 THE SUPPORT • • The support plays a critical role'in several ways in the performance of the column.- First, it governs the efficiency of the column (narrowness of peaks). The structure of the support, and the manner in which it is coated also contributes to the column efficiency. Secondly, the support can interact with the sample to. cause the chromatographic peaks to "tail" i.e. they' can be highly asymmetrical and consequently difficult - or impossible to measure. Ideally, the support should n6t interact vTith the sample but, in practice, this does occur. By careful Select ion of the support and conditions one can minimize this problem. UNIVERSITY OF IBADAN LIBRARY t 232 The "tailing” phenomenon is caused by active sites on the surface'of the support.' These sites are ones "that can form a hydrogen bond. Consequently, samples that form a strong hydrogen bond tail badly. ts * In practice, compounds such as water, glycols, alcohols acids, and amines tail severely.while carbonyl compounds.such as esters, ketones, -and aldehydes tail to a lesser degree. Hydrocarbons that do not form hydrogen bond such as the alkanes are not bothered by tailing. ̂ - . ✓ • . To eliminate or reduce the tailing problem, one modifies the sup_p ort surfac. e by.2 27 v : * (1) removing the active sites by acid and/or base washing; • • • (•2) modifying the surface by silanization, or (3) covering the active sites with the stationary. phase having polar functional groups in it. Acid washing is effective in removing mineral impuri­ 't ies from the support surface as.* well• as miscellaneous - extraneous material. Base washing does not impart any special advantage to the support that is not obtained with a well acid washed support. Acid washing' by UNIVERSITY OF IBADAN LIBRARY 233 itself is not effective in .reducing tailing but it is recommended where a polar phase is used such as the polyesters and polyglycols. Silanization, particularly with dimethyldichl.oro- silane (DMCS) is very effective in reducing tailing.' Combined with acid washing and DMCS treatment, the resulting support is recommended for most columns. Silane treatment is a very difficult process_ to control When silicone stationary phases are used, it becomes mandatory that an acid washed and DMCS treated support . be used. The silicone stationary phases, particularly when used in the 1-5%. level, are not 'effective in deactivating the support and require a s-ilane treated support.. •* ' \\ ■ The third procedure for deactivation, using a polar stationary phase, requires that the phase contain functional groups such as an .ester, an ether, a hydroxyl, and an amine group. These * functional groups ha\te strong hydrogen bonding characteristics and tie up the active sites on the support surface. These phases do not require a silanized support although, when they are used at a level of 5% or less, UNIVERSITY OF IBA AN LIBRARY 254 silsnization can be useful. When analyzing acids it is ne essary that the stationary phase contain an. acid -o deactivate the support. When-working with basic compounds such as amines, the stationary phase must contain a base to deactivate the support ; otherwise seve'* vr t.e __ tt ailing will result. • • KOH-is frequently used at a 1-21 level for the purpose A basic stationary phase such as polyethyieneimines also may be used. ' Most of the GC-supports in current use -are made from.diatomaceous earth,' also called diatomite. The ____ p diatomite is processed in several ways producing two basic types of supports. These are conveniently recognized by their colour. The particle size of supports are generally expressed in terms of screen Openings since screens are normally used to prepare them. The particle sizes normally used in GC are as follows: ^ 6.0/80 mesh; 250-177 microns 80/100 mesh; 177-149 microns 100/120 mesh; 149-125 microns. The designation 60/80 mesh means that the particles UNIVERSITY OF IBADAN LIBRARY 235- have passed through a 60 mesh screen (-60) and will not pass through the 80 mesh screen (+80). It then means that the particles are’ between 250-1.77 microns in size. The column efficiency'improves with decreasing particle size. ■ At present'the 80/100 mesh is the most popular size, but 100/120 mesh is used with increasing frequency when more efficient columns are desired. * 2.8.4.3 COLUMN TUBING . The choice of the tube used for’the column should be carefully ma'de. Both the materials of construction and its dimension must be considered., Glass, stainless steel, aluminium, and cfopper are the mate*r ials i commonly used for columns. While glass is the most inert of the tubing, stainless steel is the most widely used. . . • Glass is used in situations whe're the sample might interact with the walls of the tube. It is stan- dard operating procedure to use gl'ass columns when working with pesticides and .biochemicals such as steroids and hormones. Glass is more inert than the UNIVERSITY OF IBADAN LIBRARY 2o6 ceials and rarely causes tailing or decomposition of tie sample. Glass columns are also used generally in situations where it is desirable that the sample'be injected directly into the column. Glass column also affords visual observation of how well a column has •been packed. » . * Metal columns are used where glass is not required. Stainless steel is generally considered more inert than aluminium or copper. The hardness of the materials appears to be important in transmitting.the ' shock'’ when the column is vibrated or'tapped. Most instruments are designed to handle -1/8" outer diameter (OD) metal columns.. When glass columns are to be used, the instruments are usually equipped to- handle 1/4” OD columns. The glass can be made with a heavy glass wrall cutting down considerably on the problem of breakage. A reasonable flow rate recommended for 4 mm (id) columns'is 80ml/min.’, while for 2mm (id) columns a good rate is 20 ml/min. ’ UNIVERSITY OF IBADAN LIBRARY 237 . 2.8.4.4 UPPER TEMPERATURE LIMIT Each stationary phase has an upper temperature limit above which the column should not be operated. Most stationary phases are polymers that consist of materials having a range of molecular weights. As the column temperature, is increased, the more volatile- portion of the polymer is swept out of the column by the carrier gas. The volatile products could- also be formed by thermal degradation of the stationary phase while the column is bej.ng used. This is called "bleed" and is seen on the recorder as a rise in the baseline or as-noise. Above themaximum upper limit, tne bleed rate is very high and the column will have a relatively short life. In some cases, the bleed rate may be so high that it will not be possible to move the recorder pen off of full scale. The different stationary'phases and conditions that have been used in chromatographic analysis of hyd/rocarbons are given in Table 27 . UNIVERSITY OF IBADAN LIBRARY TABLE 27: SUMMARY OF ANALYTICAL METHOD (GC) FOR PETROLEUM HYDROCARBONS IN ENVIRONMENTAL SAMPLES Column Type Column Materials CompoundDetermined Conditions Detector Reference Packed Column Stainless Steel 12% ffap on Chrom mesh Aromatics Temp. Prog. 125°C-270oc fid2m x 2.2mm i.d w 8 0 / 1 0 0 at 4?/min. held at 270°C until n-c28 eluted carrier gas: He 12.3ml/min. Stainless Steel 3% Apiezon L Aliphatic 80-290°C at 6°/min FID 1.8m x 3.2mm on ehrom W held at 290°C until O.d 80/100 n—C2g eluted. 183 Injection Port 200- 210 C carrier gas: 12.9ml/min or He Stainless Steel 3% SE 30 gas Aliphatic Oven temp. 120°-280°C fid 2' x 0.125" Chrom Q at 8 /min. Carrier 178 30/100 gas: He Glass Column Dual column Aliphatic Injection - 250°C FID 10' x 2.0mm i.d 10% SE-30 Detector - 350°C 3% OV-17 or Col. 60°300°C at 3% OV-1 8 /min. maintained 216 on 100/120 at 300°C for 20 min. mash chrom Q Carrier gas: He UNIVERSITY OF IBADAN LIBRARY 00 1/-1 239 TABLE 27 (contd.) Column Type Column Materials CompoundDetermined Conditions Detector Reference Stainless Steel 3% W/W SE-30 A1iphatic Inj - 300°C det FID 213 (Varian 1200gc) on gas Chrom 320°C, Oven - 3m x 2.5mm 0 .d Q 100/120 mesh 30°-270°C at 6°/min carrier gas: Nn 30ml/min Varian Aerograph 1.5% RTV.502 Aliphatic Inj-300°C det-360°C Model 1200, Silicone rubber Col.-60°-332°C Carrier 197 1.9m x 0.32cm on Chrom GHP gas: 29ml/min O.d (Stainless 80/100 mesh H^-28mI/min Steel) recorder lmV Air-240ml/min atten. 8X on range 1(8x10 amp) Glass Column 1% SE-30 on Aliphatic 50~C for 4 min. then fid 10' x 2.0mm i.d Chrom WHP programmed to 350 C 100/120 at 8 /min. Carrier 220 gas: He 30ml/min Varian Aerograph 2.5% Dexsil Aliphatic Inj-325°Codet-325°C FID 10' x 1/8" 300 GC on 760/80 Prog.-100 -300°C mesh Chrom.P at 10 /min. Carrier gas: He 15ml/min 172 UNIVERSITY OF IBADAN LIBRARY 214-0 TABLE 27 (contd.) Column Type Column Materials CompoundDetermined Conditions Detector Reference 9. OPEN TUBULAR SCOT SE-30 Aliphatic T.emp. prog. 80/120^0 FID ' 174 25m x 0.5 290/310°C at 3°C/min Carrier gas: He 4ml/min 10. SCOT SE-30 Aliphatic 80°C for 4min then FID 100m x 0.65mm prog, to 270°C at 20 i.d glass 8 /min. Carrier gas: He 6ml/min 11. SCOT SE-30 Aliphatic 50 oC for 4min. then FID 200m x 0.03mm prog, to 270 C at 53 i.d (Stainless 8 /min. Carrier Steel) gas: He 6ml/min 12 WCOT SP2100 Aliphatic aet.-290°C inj.-270°C FID 30mm x 0.25mm (OKIOL) 35°C for 5min.-260°C i.d at 3 /min held for 216 20min. Carrier gas: He 13 Perkin-Elmer Apiezon L or Aliphatic 60°-220°C, 5°/min fid Model 900GC butanediol 120°-170 C at WCOT 150’x 0.01" succ inate 5min. 220 i.d (Stainless (3DS) Carrier gas: He Steel) polyester 14. 20cm x 0.3mm SE-52 Polynuclear Temp. prog. 70°-250°C FID i.d Capillary Aromatic at 2°/min. Carrier Hydrocarbonii Fig. 26.: FIJ) debtor response for n - Alkane•, ot dTifferent concentrations UNIVERSITY OF IBADAN LIBRARY 325 conditions as the samples and their retention times obtained for the individual standard. These reten­ tion times were then compared with the peaks on the chromatograms. In this way, the peaks corresponding to -the standard alkanes were fixed and the other peaks were assigned to the other members of the homo­ logous series. To check the correctness of the allocations, the logarithms of the retention times of the peaks were plotted against the number of carbon atoms. Straight line graphs were' obtained •in all cases. > . Some samples were co-injected with a mixture of the authentic standards for proper -identification and to verify the correctness of the assigned identities t • CFigs. 27, 28 and 29). The numbers associated with the peaks are \ •* expressed by Kovats1 indices and are relative to the a retention times of the linear alkanes e.g. n- pentadecane is 1500 while n-docosane is 2200. The ■ »■ Kovats' index,I,is given by the expression: ; i /t k. UNIVERSITY OF IBADAN LIBRARY 326 - p GAS CHROMATOGRAM OF -PARAFFIN MIXED STANDARD ON 1Q*/. OV-101 w jffi* r f f V T T v UNIVERSITY OF IBADAN LIBRARY UNIVERSITY OF IBADAN LIBRARY UNIVERSITY OF IBADAN LIBRARY S1/.6 co - in jf.ct i:t> w m i mr. mixi: u 329 100 log VN (subst.) - log' VN Cn-Cz) I + 100Z .log VN Cn-Cz + 1) - log VN Cn-Cz) Vx (n-C2) -= VN (subst.) < VN Cn-Cz + 1> VVT = the net retention time * (Subst) = substance whose identity is to’ be determined n-CL7* = n-paraffin with Z n-carbon at' oms ' n-C-+ ̂ = n-para£fin with Z+l carbon atoms = carbon atoms. I 3.10.3 QUANTIFICATION In gas chromatography it has. been established that the integrated area of a peak is directly propor- tional to the amount of solute eluted. Theret a■»re various methods of area measurement that have been used in chromatogram calculations. These include: O ) Geometric method (triangulation) Cb) Planimetry. ( c ) Cutting-out and weighing (d) Automatic integration. , k I UNIVERSITY OF IBADAN LIBRARY 330 3.10.3.1 PEAKS In calculating the peak areas of the chromato­ grams', the geometric method of triangulation.was used. As normal peaks have a Gaussian profile, which ^approximates to an isosceles triangle, their area can be estimated by multiplying the height by' the width at half height. Chromatogram peak area = .peak height x width af l height This can then be substituted in the formula for , calculating the concentration of hydrocarbon in a given, weight of sediment sample. Concent. ra• t. i-o n, ofr rh yo< J ro * carrb on_ = m-as- s a- s o mpl-e- f - w- hy ei4— dr ghr- o-c-ar-b-o-n 1t -A dilution / . factor x \ recovery \ Mass of peak = response factor, x peak area (detector) A The is obtained from the standard run n _ mass of standard injected r (-.standard) area- of'standard------- V■ s«t.d,, xC st. d, Amount of standard •Astd Area of standard- I UNIVERSITY OF IBADAN LIBRARY 331 Vst(j = Volume of standard injected QaL) ^std Concentration of standard A - Area of standard (cm 2) C o n cen tra tio n o f sam ple, Cg (Fg/g) ’ R F S td X V x _P_r_e__-_i_n tj_e_c_t_i_o n Sample weight,W _____ v_o.:_lu__m__e,eVx t r a c t Volume of sample injected,Vinj % Recovery RF , x A ■V Ci • e . C ( s td s e x t r a c t 1 .W s • "V s i. n ]. . % RJ Xhe u n its o f c o n c e n tra t io n are d eriv ed below : = ng x ^1 x cm x 100Q K l(m l) Hg/g |dL x Cm x g ^ % R(no u n it) ng x 1000" . g i • t = Fg/g (unit) RF std 's td RFs ''std , k i UNIVERSITY OF IBADAN LIBRARY 332 3.10.3.2 , UNRESOLVED COMPLEX MIXTURE (UCM) The unresolved complex mixture (UCM) comprising n- C14 - n - C ^ range was traced on chart paper and carefully cut out and weigned. RF Mass of, UCM in ng UCM Area of UCM in ran RF _ Mass of stds in ng std Area of stds in mnf Mass of UCM in ng Area of UCM in mm2 = RF td/ Let weight of 1 cm paper = x mg i.e. 100 mm 2 paper weighs = x mg = y - Let weight of UCM = X mg = z _1_0_0 Xm_m_ yz 29 Area of UCM Area of UCM = 100 x z mm y Mass of UCM Apea ot UCM RF std Mass of UCM = 100y- std i.e. CUIl(C~ M. x V.U.C„ . 100 M x z x*-RFy std 100 V 'UCM -x z x std extract VUCM Mass of sample f UNIVERSITY OF IBADAN LIBRARY 333 100 mm2 x m g _______ ng x /X1_____ 1000 jjj 1 mg 100 x (̂1 x min̂ x /uil x g 1000 ng g Cone, of UCM = f-lg/g Total hydrocarbon (aliphatic or aromatic) in the boiling range used (n-C^ - n-C^) = Total Resolved Peaks + UCM. UNIVERSITY OF IBADAN LIBRARY CHAPTER FOUR RESULTS AND DISCUSSION 4.1 ANALYTICAL DATA QUALITY ASSURANCE The determination of hydrocarbons in environmental samples involves steps such as organic solvent extrac­ tion,, column chromatographic cleaning and separation. The final results will depend on how the samples are carefully taken through all these steps with minimum 'loss, because part of the /samples are lost at different stages due to volatilization etc. It therefore becomes very important to report the efficiency of the extrac­ tion process in order to be able to express the i accuracy of the final results after the instrumental analysis. The reliability of the final results can therefore be checked with the results of replicate analysis of samples spiked with authentic hydrocarbon standards. ’ ¥ f 4.1.1 THE RECOVERY STUDY OF OIL IN WATER The results of the recovery study of oil in water to determine the performance of the tetrachloromethane UNIVERSITY OF IBADAN LIBRARY 335 extraction method are shown in Table 38, while the resalts of the precision study are shown in Table 39. The recovery was calculated from the formula Cs2 - Cs^ 100 where Cs Cs, concentration of petroleum hydrocarbon in sample Cs2 •~ concentration of petroleum hydrocarbon in spiked sample ... ...• Cs concentration of added petroleum hydrocarbon. The range of concentrations of oil used to spike the water samples Cl * 30mg/l) was chosen to reflect / the levels that are likely to be encountered in areas £ * covered by this study. The average recovery was 89.81 and the average error is 6.8%. The method may be judged to be reliable, since the quantity of oil in the sample can be determined with good relative standard error. The results are *” the comparable to what have been reported in/literature for similar work. Schatzberg and Jackson^ reported that the recoveries of oil concentrations above 5mg/l were, greater than 8 5%. \ UNIVERSITY OF IBADAN LIBRARY 336 TABLt . J8- RECOVERY DATA OF OIL IN WATER BY INFRARED bîECl'JKOfWt? AQ: !ETPIC METHOD .. — . Amount of Oil Amount of Oil Added mg/1 Recovered mg/1 % Recovery 2.00 1.50 75.0 1.69 84.5 3.00 2.70 90.0 2.55 85.0 5.00 4.58/ 91.6 4.72 94.4 20.00 18.20 91.0 f/ T9.33 96.7 30.00 126.78 89.3 28.60 95.3 * X f 89.75% SD = +6.2 RSD =6.8% ■ • ' • . k / 1 ! UNIVERSITY OF IBADAN LIBRARY 337 TABLE 39': PRECISION DATA OF OIL IN WATER BY TETRACHLORQMETHANE EXTRACTION. WITH INFRARED SPECTROPHOTOMETRIC METHOD Amount of Oil Amount of Oil Added mg/1 Recovered mg/1 . 5.00 4.53 5.00 4.7 2 5.00 5.28 . 5/00 * \ 4.18 5.00 i// . 4.32 5.00 3.80 5.00 5.07 5.00 /i __ 4.62 / 5.00 4.75 5.00 4.56 . - X = 4.59 SD = ±0.42 ’ ¥ RSD = 9.23% , V UNIVERSITY OF IBADAN LIBRARY 338 The precision can be said to be equally good because the results reflect a good reproducebility with the level of relative standard deviation of 9 . 2 3 1 . The high mean percentage recovery coupled with the good precision further confirmed why tetra- chloromethane has been the choice for hydrocarbon extraction from water. Its high extraction efficiency for both fresh and weathered oil makes it a suitable extraction solvent except for its toxicity. 4.1.2 THE RECOVERY STUDIES OF PETROLEUM HYDROCARBONS IN SEDIMENTS The results of the recovery studies of the alkanes and aromatics are shown in Tables 40 and 41 respectively. The two methods compared are the reflux and soxhlet as earlier discussed in sections 3.9.2.1 and 3.9.3. The results of the percentage recovery in Table 40 for the alkanes showed that both methods gave comparable results but the reflux (the method used for this work) seems a little superior to the soxhlet method, especially « in the higher hydrocarbon (> C20) region. / y ^ / UNIVERSITY F IBADAN LIBRARY 339 TABLE 40: PERCENTAGE RECOVERY OF ALKANES FROM SPIKED SEDIMENT SAMPLES BY TWO DIFFERENT EXTRACTION METHODS. ALKANE R1 R2R EFLRU3X R4 R5 Rx ALKANE SI S2 SSO3X I1LET S4 S5 Sx + C16 45.3 53.0 42.0 49.0 58.1 49.6±6.3 C16 61.8 49.6 62.5 58.7 54.8 57.5 *5.4 C17 69.2 75.3 67.2 63.0 69.4 68.8*4.4 C17 75.0 70.3 71.3 66.1 70.2 70.6 1-3.2 Pristane 85.1 88.4 83.5 80.7 86.2 84.8i2.9 Pristane81.2 78.4 78.7 72.1 76.4 77.4 i 3.4 ' CI8 65.9 78.6 85.2 63.8 69.6 72.619.0 C18 69.1 64.9 79.0 70.0 72.1 71.1 i 5.2 Phvtane 76.3 80.0 82.0 75.7 78.3 78.512.6 Phytane 72.5 75.2 81.3 69.5 73.4 74.4 ± 4.4 C20 78.0 76.8 90.8 77.6 82.2 81.1+5.8 C20 76.3 74.6 86.2 72.5 81.7 78.3 * 5.6 C22 85.8 88.5 91.3 82.5 85.1 86.6*5.1 C22 73.3 78.2 75.8 70.9 71.9 74.0 t 2.7 C23 98.5 102.7 106.1 95.3 97.4100. ±4.3 C23 77.4 89.3 84.1 81.4 82.5 82.9 i 4.3\ C24 92.8 96.4 102.7 94.7 95.2 96.413.8 C24 88.7 72.0 63.7 66.8 64.9 71.2*10.3 \ C2-6 86.7 89.3 92.4 78.4 88.3 86.615.2 C26 83.0 83.5 82.6 78.5 79.5 81.4 + 2.3 C28 80.2 85.5 88.9 79.0 80.4 82.8t4.2 C28 70.4 79.7 76.3 75.8 67.7 74.0 1 4.8 C30 78.4 73.0 75.4 70.5 71.2 73.713.2 C30 65.8 74.6 61.3 65.9 68.5 67.2 1 4.9 C32 76.2 70.4 74.0 69.4 68.5 71.713.3 C32 75.5 70.6 75.9 72.2 70.6 73.0 t 2.6 - - - - C34 64.4 62.1 57.3 62.2 64.9 62.2 l 3.0 i UNIVERSITY OF IBADAN LIBRARY 340 TABLE 41: PERCENTAGE RECOVERY OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) FROM SPIKED SEDIMENTS BY TWO DIFFERENT METHODS. REFLUX • SOXHLET PAHS Rl* r2 R3 R4 R - R* Si S2 S3 S4 Sr s* Phenanthrene & Anthracene 74.5 53.1 43.1 82.7 76.7 66.0± 17.0 78.1 83.2 64.8 63.6 63.8 •70.7t09.3 * Fluoiranthrene 56.2 72.4 54.3 75.4 68.4 65.3± 09.6 67.0 86.9 59.4 75.1 68.3 71.3*10.3 pyvene 62.3 70.6 60.7 78.9 ">0.2 68.5± 07.3 61.4 84.7 56.7 79.7 62.3 67.81^.3 b 1,2-Benzan- i \ thracene 67.1 72.3 63.7 75.2 73.1 70.3+ 04.7 73.5 81.4 52.2 77.9 75.4 7 2.1+11 .'5 7,12-Dimethy- Benzanthracene 63.5 75.2 61.3 80.3 74.2 70.9+ 08.1 62.7 73.5 54.6 68.2 60.2 77.8+07.3 3-Methy- Cholanthracene 24.2 13.6 16.8 14.8 18.3 17.5+ 04.1 32.5 38.5 24.3 37.3 35.4 33.6+05.3 * i f' % / f I s UNIVERSITY OF IBADAN LIBRARY 341 In both methods, lower hydrocarbons C < C ^ ) were either lost completely or with very poor recovery. ✓ The loss might be due to evaporation because the hexane extract in each case was evaporated to dryness \ prior to both the gravimetric and gas chromatographic analysis. However, most of the samples’ showed chroma­ tograms of heavily weathered oil with the lower hydro­ carbons already lost. . The percentage recoveries for the aromatics shown in Table 41 gave the-' soxhlet a slight edge over the reflux but with a higher level of erro/s. Naphthalene, dimethynaphthalene and acenaphthene were lost in both methods. This may be due to the same reason given above for the lower alkanes. £ « Both methods also gave poor recoveries for 3-methy- cholanthracene. * • The precision data for both the .reflux and soxhlet * « method are given in Table 42. Reflux method recorded a higher concentration of hyd•r o*carbons than the soxhlet method but the soxhlet method has a superior reproduci­ bility than the reflux method. The two results can be \ . . k • UNIVERSITY OF IBADAN LIBRARY - 342 TABLE 42 : PRECISION DATA OF HYDROCARBONS IN SEDIMENTS BY REFLUX AND SOXHLET EXTRACTION METHODS Reflux Jlg/g Soxhlet |4g/g *1 1.170 S1 0.990 *2, 1.079 S2 0.786 R3 0.864 S3- 0.691 R4 0.902 S4 0.650 *5 1.014 S5 0.721 ' R6 0.815 ,S6 1.123 *7 0.855 S7 0.905 *8 1.404 S8 1.001 R9 0.766 / i " • S9 0.884 0.749 S10 o ini X 0.962 Y 0.853 SD 0.21 SD 0.15 RSD 21.5% RSD 17.9% * *■ UNI OHVERSITY OF IBADAN LIBRARY 343 tested for their comparability by applying both the F-test and t-test to see if there is any significant difference between the two means. The objective of the tests is to show whether the difference observed in the two means is as a result of indeterminate error or that the two means are essentially different. 4.1.3 STATISTICAL ANALYSIS 249 Mean (X) = Z X N CD where X-represent individual experimental result obtained N-Total number of results in the set, / T ^ i Standard deviation (s) = . . C2) i=l______ M N - 1 In comparing two experimental means a pooled standard deviation is used in place of the expression given in C2) above. . . pooled s = ( % - D s J + (N2-l)S^ C3) \ | M - K UNIVERSITY OF IBADAN LIBRARY 344 K — sets of data M = + N2 F-test is used to establish if the two sets have similar precisions. v . This test uses the ratio of the variances of the two sets / where si ̂ S2 If the standard deviations of the two sets of data agree at a reasonable confidence level, then the l * mean results can be compared, using the t-test. t = (X - Y) N1N2 ......... C5) s \ . V » 2 X is the mean of determinations (reflux) Y the mean of N2 determinations (soxhlet) s the pooled standard deviation. , v UNIVERSITY OF IBADAN LIBRARY 345 X = 0.962 (Table 76) Y = 0.853 (Table 76) using equation (2) above \ s for reflux replicate analysis (S-^)=0.21 s for sox’nlet replicate analysis (S?)=0.15 F-test (equation (4)) (F■ e =F expr ected)' F exp. = (0.21)_ = 1.96 (0.15) / Fcrit at t îe 95V confidence level is >3.14. r- Since the value calculated is less than the tabulated '• value (1.96^ 3.14), it means that the standard deviations have no significant difference, so it is possible to proceed to use the t-test. pooled s = (10-1) (0.21) 2 + (10«rl) (0.15)2 = 0.18 1 0 + 1 0 - 2 t = 0.962 - 0,853 100 07, Xv8 1 0 = 1.36 “ / s l UNIVERSITY OF IBADAN LIBRARY 346 t18 95? = ^*^9 (i.e. t at 18 degree of freedom • ajnfefder t95?q confidence level from tcble = 2.09). Since t-value calculated, 1.36 is less than t - from statistical table 2.06; it means that there is no significant difference between the two means. This implies that the two methods of extraction gave comparable results. The two methods were applied in the analysis of / a reference sample (00039/IAEA Monaco) and the results /\ are presented below in Table 43. The chromatograms of the reference sample for the reflux and soxhlet / methods are shown in Figures 30 & 31. : . v 4.2 CONFIRMATION OF THE HYDROCARBON COMPOUNDS Two different columns were used to establish the correct allocation of peaks to the various hydrocarbon compounds in the samples analysed. The columns were 109«0v - 101 on chromosorb WHP 80/100 mesh and 3% SE-52 on chromosorb iV.AW/Dmcs 100-120 mesh. The chromatograms from both columns have the same hydrocarbon arrangement i UNIVERSITY OF IBADAN LIBRARY 347 TABLE 43; RESULT OF REFERENCE SAMPLE (00039XAEA/ MONACO) EXTRACTED BY BOTH REFLUX AND SOXHLET METHODS ifeflux Soxhlet -1_______I____ _ __________ 1 2 1 2 n-Alkanes 2.28 2.49 1.83 1.91 UCM 84.04 92.07 67.67 70.12 /. Total Aliphatic Hydrocarbons 86.33 94.56 69.50 72.03 X ! 90.44 70.7t6 . SD + 5.83 + 1.79 RSD 6.4% 2.53 i UNIVERSITY OF IBADAN LIBRARY 348 Fi g . 30 : Chromatogram of a reference sample extracted by reflux method. UNIVERSITY OF IBADAN LIBRARY / Fig. 51: Chromatogram of a reference sample extracted by soxhlet method. UNIVERSITY OF IBADAN LIBRARY C 17 • P r C23 Gas chromatogram of n-paraffin mixed standard on icn 0V-101. UNIVERSITY OF IBADAN LIBRARY ' 351 UNIVERSITY OF IBADAN LIBRARY i 552 vf i.e. C1ir0> - C-o26) as can be seen in the two chrona- togrims given.below•(Figs. 52 and 55). 5% SE-52 column yielded quantitative separation . • y of the n-C-^y and pristane, and the n - C-̂ g and phytane, u while the 10% 0V-101 was able to separate n - C,g and phyt.ane but:, with n - C ^ d a n d pristane coming out as a .single, peak. SE-52 was also’ used for the aromatics. n - C-o,b- alkane standard was used as an internal standard for ’ the aliphatic fraction while phenanthrene was used for the aromatics. . 4.3 RESULTS. ’ 4.3.1 SURFACE WATER RESULTS • ■ The hydrocarbon content of water samples from the major river systems around Lagos and the Niger Delta area of Nigeria was determined by infrared spectrophoto- metric (IR) method and for more detailed information some of the samples were also analyzed for the aliphatic hydrocarbons by oas chromatographic (GC) method. The results of the analyses of the samples are set out in % UNIVERSITY OF IBADAN LIBRARY 353 T a b l e s 44.1 - 4 4 , 1 2 . T h e s a m p l e s a r e g r o u p e d u n d e r t h e d i f f e r e n t r i v e r ' s y s t e m s s t u d i e d . Tables 44(f-12) sh/o w the result*s of the 'IR and the GC for samples from 12 river systems with the range (R) and the arithmetic mean (X) for each system given below it. The table’s showr the hydrocarbon level for both-the 1984 (wet) and 1985 (-dry) seasons of some of the stations where relevant. 1 • * 4.3.1.1 LAGOS AND LEKfrl LAGOONS On the Lagos and Lekki Lagoons, the hydrocarbon levels as determined by the IR method for the wet season ranged from 1.64mg/l (Epe •- 855) to il.40mg/l (Lever Brothers’ Discharge - 845) with an average of 5.60mg/l. The GC values ranged from O.Olmg/1 to 0.27mg/l. with an average of 0.16mg/l. This river system had consistently nigh values for’ both methods, with stations 086 (off Federal Palace Hotel)-, 087 (North of NNPC facility on Lagos Harbour), 847 (Okobaba Sawmill) , 854 (off Ologogoro) and 85.6 (off Iwopin) having above 3.00mg/l .by IR and 0.10mg/l by GC. UNIVERSITY OF IBADAN LIBRARY 354 The values of hydrocarbon (by IR) found during- • - ■» , * . the 1985 (dry) season for all the stations were-below 0.50mg/l with the highest being 0.4.1 mg/T (East of Ooboyi Creek). The mean value recorded for the 19S5 dry season samples wa.s 0.25mg/l, which is relatively low compared with 5.60mg/l.'recorded for the 1984 (wet) • • season. Within the Lagos and Lekki Lagoons, the observed trend is that most of the high values recorded were from points located near oil activity area (087 - NNPC facility) along.(boat or ship traffic routes or near- effluent discharge points from the industrial houses bordering the Lagos Lagoon (Federal Palate . Hotel, Lever • Brothers ' discharge point and a point off the University of Lagos - 849). 4.-3.1.2 BENIN RIVER SYSTEM The hydrocarbon levels recorded during the 1984 (wet season) varied from a level not detectable by both the IR and the GC (878 - Ossiomo river) to 50.10 mg/1 (134 - Asagba on Ethiope river)*, the average value of 7.07mg/l (IR) was recorded. Other points \ where high values were recorded are Dudu Town.(837), Olagua Creek at Benin river confluence (838), Robb in \ UNIVERSITY OF IBADAN LIBRARY o:>:> Creek (057), and Ogharife field effluent canal (0-2''.. . These points, were located next to towns (837) and oil field (JO - 2) . ' “ : The values for the points sampled in the 1985 (dry season) were low with range 0.15 - 0.32mg/l and mean value of 0.23mg/l‘ (IR). 4.3.1.3 ESCRAVOS RIVER SYSTEM ' Points on the Escravos river system recorded a range’of values from 3.80mg/i to 17. S0mg/1.with a mean value of 9.17mg/l; The highest values were at Upomani oil discharge station (831), Jones creek at Jones creek field (360), Chanomi creek (833), Aghigho (055) and an unnamed creek- east of Jones creek (839)“. There was an appreciable decrease in the levels recorded during the 1985 dry- season, with the Escravos Terminal recording the highest for the period (0.71mg/l) All the points where high values were recorded Jj.'ere well situated within the oil activity areas, or . along the water traffic routes, which m a y .there fore account for the observed ..high levels of hydrocarbon recorded. UNIVERSITY OF IBADAN LIBRARY 556 4.3.1.4 FORCADOS - KARRI RIVER SYSTEM The hydrocarbon levels obtained during 1984 (wet season) ranged between 0.60mg/l (Warri river upstream of refinery Jetty at Ogunc Channel,- 861) and 7.70mg/l (Keremo on Warri river - 865). High values were also recorded at Unenuchi (Okpari creek - 372), Forcados river above Burutu (866),. Ughelli ( (051), Warri river field (053), unnamed creek draining Odidi field (859), and Forcados river above Obotebe (-865), . .‘All the stations sampled in'1985 dry season had values between 0.11mg/l (unnamed creek opposite Ajujn field - 862) and 1.40mg/l (Forcados river below Burutu - 867). -Most of the stations were located close to oil installations or on boat traffic route and close to towns (e.g. Burutu stations). 4.3.1.5- RAMOS RIVER SYSTEM ^ The 5 samples analyzed gave values which ranged from 1.10mg/l (Nikorogba creek - 869) to 2.20mg/l (Ramos estuary northeast of Aghoro - 038). No sample was collected during the 1985 dry season sampling trip. UNIVERSITY OF IBADAN LIBRARY 357 4 •. 3.1.6 NUN - EKOLE - BRASS The average value obtained for the 1984 wet period samples was 3..39mg/l, with a range of values from a non-detectable value at a point below Berenabiri (S72) to 17.60mg/l - Raima/Patani floodplain. High values were also, Recorded at Agip slot (023) , Taylor creek (036), Diebu creek (043), Brass river mouth west side C094B) and Ekole creek (S25). Agip slot, Taylor creek and Okoso/sandy floodplain (260) recorded high hydrocarbon levels for both wet ‘and dry seasons. '■4.3.!. 7 t) RASH I RIVER SYSTEM On the Orashi river system the levels of hydro­ carbon recorded ranged from 0.20mg/l - Sombreiro river mouth west side (.881) to 38.90mg/l - Ahoada (022) in 19'84 wet season. The average was 6.52mg/l. Stations where high values were recorded for both wet and dry seasons included Onosi near Ebocha (013) , Oguta Pontoon crossing (014), Lake Oguta (016), Enwhe flow station (035), Okogbe west (252) , Okogbe East (801), and Okarki (821). UNIVERSITY OF IBADAN LIBRARY 358 Dry season (1985) values ranged between 0.10mg/l and 1.80mg/l with a mean of 0.60mg/l. * - v 4.3.1.8 'BONNY - NEW CALABAR RIVER SYSTEM The range of hydrocarbon values was from 0.30mg/l, Bodo creek (121) to 70.70mg/l Elele Alimini (236). High values were recorded for Elele Alimini in both the 1984 and 1985 samples. Other points where appreciable levels of hydrocarbon were recorded are Okrika refinery Jetty (018), Umuochi-X0 20), Port Harcourt Harbour (235a), Bakana (807), Iwofe (808) and a point north of Alaocha (810). A parffrom Elele Alimini, all these other points had values below 0.70mg/l fo*r the 1985 dry season. f 4.3.1.9 IMP RIVER SYSTEM The highest level of hydrocarbon was recorded at Azumini near Aba (806) - 10.10mg/l and the lowest was at the new bridge on Imo river (078) - 0.80mg/l. Other stations of note were Kono waterside (128) , Isirc'iri flow station (816) , Otamiri (818) and Imo river mouth east side (880). Only Azumini was sampled in 1985. • v The level of hydrocarbon was down to 2.00mg/l. UNIVERSITY OF IBADAN LIBRARY 559 4.3.1.10 CROSS RIVER - CALABAR RIVER SYSTEM High levels of hydrocarbon were recorded during 19S4 wet season on Calabar river (070) - 4.S7mg/l, Calabar between marker 31 and 32 (072) - 4.20mg/l, Cross river floodplain (805) - 6.90mg/i, Calabar tributary (826) - '3.40 and the new Calabar Port Complex (827) - 2.30mg/l. Only stations 805 and S26 were sampled for the 1985 dry season. The values recorded were 0.30 and 0.50mg/l respectively. " . 4.3.1.11 KADUNA RIVER SYSTEM The two points sampled in 1984 on the Kaduna refinery effluent channel gave 9.90 and 6.50mg/l for the points down stream and upstream respectively. The other two points located on river Kaduna gave 7.20mg/l - Doka park (843) and 4.30mg/l for the River Kaduna floodplain at Malali (844). . 4.3.1.12 IBADAN Samples taken from Agodi garden on Ogunpa river and Asejire river (Ife-Ibadan Road) did not show any detectable level for both the 1984 and 1985 seasons. i UNIVERSITY OF IBADAN LIBRARY 360 TABLE 44 . 1 : TOTAL HYDROCARBON CONCENTRATIONS IN WATER SAMPLES FROM LAGOS AND LEKKI LAGOONS BY INFRARED • SPECTROPHOTOMETRIC (IR) AND GAS CHROMATOGRAPHIC (GC) METHODS (mq/1) •Wet Season Dry - Station Seasonss Code 1 IR . GC IR ‘ - - - 1984 1984 ’ 1985 1- 086 5.60 • 0.14 NA 2. \ 087 7.60 0.27 0.30 3. 845 11.40 0.21 NA • 4*- 847 4.60 0.13 _ NA 5. 848 9.50 0.01 0.40 6. 849 • • • 3.50 o.io.. • 0.21 7. 850 3.00 0.41 8. 851 4*00 r 0.10 9. 852 8.00 . 0.21 854 5.04 0.20 NA 11. 855 1.64 0.03- NA 12. 856 4.50 *0.16 0.11 13. 857 4.40 _ - NA M2anf X 5.60 0.16 0.25 F&nge, R 1.64-11.40 0.01-0.27 0.10-0.41 UNIVERSITY OF IBADAN LIBRARY • Ho 361 TABLE 44.2; TOTAL HYDROCARBON CONCENTRATIONS IN NATER • ' SAMPLES FROM BENIN iRIVER SYSTEM (mg/1) ‘ . _ Vfet Season Dry Station SeasonSN Code IR GC IR 1984 1984. . 1985 1. ' 057 8.70 1®. ANA 2. 134 30.10 0.90 • 0.32 3. 311 3.10 • 0.03 .0.13 ■ 4. 347 5.30 ' 0.-04 NA 5. 804 0.90 NA . NA 6. 835 4.10 ND NA 7. 836 ' 2.20 NA „ - NA 8. • 837 4.80 • ' 0.11 NA 9. 838 13.90 0.20 NA 10. 877 1.10 ND. ■ NA 11. 878 ND ND NA 12. 884 • 6.30 0.14 NA 13. 0-1 2.10 0.01 ■NA 14.- 0-2 16.40 0.55 NA . Mean, X 7.62 . 0.25 0.23 Ifenge, R ND-30.10 ND-0.90 0.13-0.32 UNIVERSITY OF IBADA LIBRARY 362 TABLE 4'4~. 3 : TOTAL HYDROCARBON CONCENTRATIONS IN WATER SAMPLES FROM ESCRAVOS RIVER SYSTEM Wet Season Dry Season SN . StationCode IR GC IR 1984 1984 1985 1. • 054 3.80 0.04- 0.71 2. 055 •8.00 0.15 0.21 3. 098 9.50 NA NA 4. 360 15.00 0.24 NA 5. 362 14.30 - NA 6. 831 17.50 3.36 • NA 7. 832 5.50 n a 0.20 8. 833 9.60 0.27 • . 0.11 9. 834 5.00 0.01 ' ‘ 0.43 10. 839 . 7.00 0.12 NA 11. 840 5.70 NA NA Mean, X 9.17 0.70 0.33 Range, R 3.80-17.50 0.01-3.36 0.11-0.71 UNIVERSITY OF IBADAN LIBRARY 303 TABLE 44.4: T OTAL H Y D R O C A R B O N CO N C E N T R A T I O N S IN W A T E R SAMPLES FRO M FORCADOS R IVER SYSTEM Wet Season Dry Season SN bLdtionCode IR GC IR 1984 1984 1985 1. 040 0.90 NA 0.21 2. 050 1.00 NA 0.21 3. 051 1.80 0.03 0.11 4. 052 1.00 NA 0.32- 5iV 053 2.10 0.03 NA 6. 351 1.80 0.01 0.64 7. 352 2.80 NA NA 8. 353 5.10 NA 0.61 9. 372 7.20 0.27 0.41 10. 858 6.40 NA 0.20 11. 859 0.80 0.03 NA 12. 860 2.00 0.01 0.11' 13. 861 0.60 0.01 0.51 14. 862 6.70 NA 0.11 15. 863 7.70 0.01 0.12 16. 864 1.50 NA 0.20 17. 865 2.00 0.03 0.23 866 4.70 0.12 0.40 19. 867 5.60 NA 1.40 Mean, X 3.25 0.07 0.36 Range, R 0.60-7.70 0.01-0.27 0.11-1.40 UN *l-»•00IVERSITY OF IBADAN LIBRARY 364 TABLE 44.5; TOTAL HYDROCARBON CONCENTRA- » TIONS IN WATER SAMPLES FROM RAMOS RIVER SYSTEM Wet Season Dry Season SN StationCode IR GC IR 1984 1984 1985 1. 038 2.20 0.04 NA 2. 382 1.10 0.01 NA 3. 869 1.10 NA NA 4. 870 2.10 0.02 NA 5. 871 16.00 NA NA Mean, X 4.50 0.02 - Range, R. 1.10-16.00 0.01-0.04 — UNIVERSITY OF IBADAN LIBRARY 365 TABLE 44.6: T OTAL H Y D R O C A R B O N CONCENT R A T I O N S IN W A T E R S A M P L E S - F R O M NUN-EKOLE- BRASS R IVER SYS T E M ~ Wet Season Dry Season SN StationCode IR GC IR 1984 1984 1985 1. 023 2.70 NA 0.97 2. 024 1.50 NA NA 3. 030 1.60 NA 0.70 4. 036 6.50 0.08 1.40 5. 043 3.20 0.03 NA 6. 094A 6.10 NA NA 7. 094B 0.60 0.05 NA 8. 260 1.60 NA 1.00 9. 281 1.80 NA NA 10. 803 17.60 0.31 0.20 11. 825 1.50 0.07 NA; 12. 872 ND NA NA 13. 873 2.80 0.01 NA 14. 874 1.80 NA NA 15. 875 1.50 NA NA Mean, X 3.63 0.09 0.85 Range, R. NI>17.60 0.01-0.31 0.20-1.40 UNIVERSITY OF IBADAN LIBRARY 366 TABLE 44.7: TOTAL HYDROCARBON CONCENTRATIONS IN WATER SAMPLES FRCM ORASHII.RIVER SYSTEM'"! : * Wet Season Dry Season SN StationCode IR GC IR 1984 1984 1985 1. 013 5.00 0.41 0.90 2. 014 2.50 0.11 0.51 3. 016 4.90 0.37 0.11" 4. 021 3.20 NA 0.20 5. 022 38.90 NA 0.31 6. 035 3.60 0.06 NA 7. 250 8.20 NA NA 8. 251 0.50 NA NA 9. 252 4.00 0.07 1.80 10. 262 NA NA 0.10 11. 801 4.10 0.32 0.30 12. 802 3.90 NA NA 13. 819 20.00 0.01 0.20 14. 820 NA NA 1.20 15. 821 3.10 0.22 1.00 16. 824 1.30 NA NA 17. 881 0.20 NA NA 18 c 882 0.90 0.01 NA Mean, X 6.52 0.18 0.60 Range, R. 0.20-38.90 0.01-0.41 0.10-1.80 UNIVERSITY OF IBADAN LIBRARY 367 TABLE 44.8: TOTAL HYDROCARBON CONCENTRATIONS IN WATER SAMPLES FROM BONNY-NEW CALABAR RIVER SYSTEM Wet Season Dry Season SN StationCode IR GC IR 1984 1984 1985 1. 018 2.40 0.04 0.51 2. 020 1.70 0.02 0.50 3. 093 6.90 NA NA 4. 121 0.30 0.01 0.61 5. 233a 39.70 0.01 0.20 6. 236 70.70 0.53 1.80 7. 807 42.20 0.22 0.40 8. 808 1.60 0.04 0.10 9. 809 1.60 0.01 NA 10. 810 2.00 0.05 0.40 Mean, X 16.91 0.13 0.57 tenge, R. 0.30-70.70 0.01-0.53 0.10-1.80 UNIVERSITY OF IBADAN LIBRARY 368 TABLE 44.9: TOTAL HYDROCARBON CONCENTRATIONS IN WATER SAMPLES FROM IMO RIVER SYSTEM Wet Season Dry Season SN StationCode IR GC IR 1984 1984 1985 1. 078 0.80 NA NA 2. 128 3.20 0.04 NA 3. 806 10.10 0.14 2.00 4. 813 NA NA NA 5. 814 4.00 0.09 NA 6. 816 3.00 0.08 NA 7. 817 3.70 NA NA 8. 818 2.60 0.06 NA 9. 880 1.60 0.02 NA Msan, X 3.63 0.07 Range, R. 0.80-10.10 0.02-0.14 UNIVERSITY OF IBADAN LIBRARY 369 U L E 44.10: TOTAL HYDROCARBON CONCENTRATIONS IN WATER SAMPLES FROM CROSS RIVER-CALABAR RIVER SYSTEM Wet Season Dry Season SN StationCode IR GC IR 1984 1984 1985 1. 070 4.87 0.35 NA 2. 071 2.00 NA NA 3. 072 4.20 0.82 NA 4. 079 1.10 0.03 NA 5. 210 3.00 NA NA 6. 805 6.90 0.65 0.30 7. 811 1.70 NA NA 8. 812 0.80 NA NA 9. 826 3.40 0.06 0.50 10. 827 2.30 0.03 NA / Mean, X 3.03 0.32 0.40 Range, R. 0.80-6.90 0.03-0.82 0.30-0.50 UNIVERSITY OF IBADAN LIBRARY 370 TABLE 44.11: TOTAL HYDROCARBON CONCENTRATIONS IN WATER SAMPLES FROl KAQJNA RIVER SYSTEM Wet Season Dry Season SN Code IR GC IR 1984 1984 1985 1 141A 9.90 0.11 NA 2 141B 6.50 0.07 NA 3 843 7.20 NA NA 4 844 4.30 NA NA Mean, T 6.98 0.09 - Range, R 4.30-9.90 0.07-0.11 _ TABLE 44.12: TOTAL HYDROCARBON CONCENTRATIONS IN WATER SAMPLES FROl IBADAN Wet Season Dry Season SN StationCode IR GC IR 1984 1984 1985 1 Ag-1 ND ND ND 2. As-2 ND ND ND ND = Not detected NA Not analyzed. UNIVERSITY OF IBADAN LIBRARY 371 4.5.1•i3 UTOROGU SWAMP AND OKPART RIVER . The results of the IR analyses of the hydrocarbon levels at the various points sampled during the 1984 and 19S5 sampling periods are displayed in .Table 45. The area is divided into 3 parts - impacted swamp, upstream and downs'tream. The values recorded for the swamp during the 19S4 vet season range between 2.18 and 10.-50mg/l with a mean value of 4.82mg/l. The highest hydrocarbon levels recorded were for points (10!5mg/l), E ‘(7.89mg/l) , C. (6. 70mg/l). and A (5.10mg/l). -All the points within the swamp recorded appreciable levels of- hydrocarbon because they were all impacted by the spilled crude oil Points- P and R (transect) which were upstream • points recorded hydrocarbon values -between 0.49 and O.78mg/l with a mean 0.68mg/l. All the other points downstream from 0 (transect) to J (transect) gave values between 0.17 and 0.95mg/l with a mean 0.,49mg/l. During the early 1985 sampling (dry Season) most of the points within Utorogu .swamp had dried up but samples were collected from .3 points which happened to be hidden by trees and shrubs from the direct impact of UNIVERSITY OF IBADAN LIBRARY 372 TABLE 45' TOTAL HYDROCARBON CONCENTRATION IN WATER SAMPLES AT UTOROC-U _ SWAMP AND •OKPARI RIVER IN BENDEL STATE BY INFRARED SPECTROMETRIC (IR) METHOD (mq/1). CONCENTRATION {mg/1} STATION OCT-NC>V JAN-FEB CODE 1984' 1985 IMPACTED SWAMP 1 A 5.10 4.41 2 • B 3.95 4.67 3' ' c i NA NA- 4 ; s . 4,24 2.29 5 C 3 ^ 10.50- NA . S C 4 4.30 ' NA 7 D NA NA 8 E 7.89 NA 9 F 2.49 NA 10 G 1 2.18 2.29 11 G 2 2.23 1.78 12 G 3 6.70 ND 13 G 4 3.41 ND X 4.28 3.09- R 2.18-10.50 1.78-467 UNIVERSITY OF IBADAN LIBRARY 375 TABLE 45 (contd.)' STATION OCT-NOV 0AN-FEB CEDE 1984 1985 UPSTREAM- 1* R1 — 0.78 ND 15 *2 o.78 , ND 16 *3 • 0.65 ND 17 P 0.49 ND X 0.68 ND 49-0.78 ND DCXWSTREAM 18 °1 0.56 4.29 19 °2 0.79 • 0.43 20 N 0.51 0.79 21 V 0.50 ND 22 K1 0.47 ND ' 23 K 2 0.19 0.23 24 *3. . 0.46 ND ’ 25 T 0.59 ND 26 U 0.36 ND 27 L 0.95 ND 28 J1 0.30 ND 29 J2 0.17 0.26 30 J3 0.54 ND X 0.49 1.20 R 0.17-0.95 ND-4.29 UNIVERS o•ITY OF IBADAN LIBRARY 574 • the sun. The values recorded were 4.41mg/l' (A), 4.67ag/-l (B) and 2.29mg/l (^2 ) * Points; and. G2 bordering the swamp on Okpari river had 2.29 and 1’. 78mg/l respectively.- Points P and R did not record any detectable 1 level upstream. Downstream, point 0-̂ recorded 4.29 ng.'l. Apart from points O 2 (0.43mg/l), Agbokiama-N (0. “9ing/l) , Ekai-gbodob (0.23mg/l) and the mouth cf Okpari to Forcados - J 2 (0.26mg/l), all the other points did not give any detectable level: In June-July 1985 (wet season)- sampling trip the swamp was flooded and Okpari river w.as. also flooded. All the water samples'analyzed had levels below the detection limit of the IR method (50 ppb) used. \ 4.4 DISCUSSION . . • THE INFRA RED RESULTS ' The IR results recorded for most of the stations sampled during the 1984 wet season were quite high. Some of the values were more than 10mg/l (845, 134, 838, 0-v2, 360, 562, 831 , 803, 022, 819 , 233a, 236 and UNIVERSITY OF IBADAN LIBRARY 575 51" , which is rather very high for water when c:-~sred with the values reported e liter a turret2?1 ’252) which . ' . are from a few microgram per litre (ppb) to-a few udlilgrams per litre (ppm) 6mg/l. Although most of Xj.t values reported were for oceans and seas where dilution is a major factor in preventing- the accummula- ti:n of hydrocarbon in the water column. Most of these values reported were determined by gas chromatographic r;: :u (aliphatic, aromatic or total hydrocarbons) or florescence spectrometry (for aromatics).. The values free, these two techniques will always be'lower than the IR values. The difference can also be seen when the IR values reported in Tables 44(i-12) are compared uith the corresponding GC values for same sample. AJL1 the GC values except one - Upomani ((831) with 5.36mg/l) were below lmg/1. Some of the reasons that, may be given for the higher IR values above the GC values are that the IR spectra method detects many hydrocarbons, including fatty acids, which can be a’ large component of non-petroleum hydrocarbons. UNIVERSITY OF IBADAN LIBRARY 376 .In GC quantification only the hydrocarbons 'eluting from the column between n - C,i U„ and n - C_J,4 were quantified, because detector sensitivity is poor for the long-chain hydrocarbons. Thus, the values are a lower limit for the total hydrocarbons. There was little contribution added by hydrocarbons eluting before n - C-̂ q and hydrocarbons eluted from the column past n - C^. Because clean-up steps were used prior to GC the non-hydrocarbon components of the oil are not measured. IR also permit's the measurement of many relatively volatile hydrocarbons, which may be lost during the evaporative stage for GC analysis. ‘ In spite of all these handicaps, one interesting thing of note in the results presented in Tables 44 (1-12) is that those samples with high IR values also gave corresponding high GC values, which goes on to • show, that the non-diagnostic factor against the IR Tiot withstanding, the results can still be used as good indicator in monitoring system of hydrocarbons in the environment. This point is clearly illustrated % UNIVERSITY OF IBADAN LIBRARY 37 7 by the following data: IR (mg/1) GC (mg/ Lever Brothers' discharge Point OA Lagos harbour (.845) 11.40 0. 21 As§gba (Ethiope river) (154) 30.10 0.90 Dudu town (Benin river) (857) 4.80 0.11 Olagua Creek (Benin Confluence) (838) 13.90 0.20 Ogharife field effluent canal (0-2)' 16.40 0.55 Upomani discharge (851) 17.50 5. 36 Unenuchi (Okpari Creek) (372) 7.20 0.27 Kaima/Patani floodplain (803) 17.60 • 0.31 Elele Alirnini (236) 70-. 70 0.53 Bakana (up) (807) 42.20 .0.22 Cross River floodplain (805) 6.90 0.65 kaduna refinery effluent channel downstream (Romi river) (141 A) 9.90, 0.11 There is a significant positive correlation between' the GC arid IR values (r = 0.668). ^ The IR'results for the 1984 and 1985 reported in Tables 44 (1-12) and 45 show that there was a sharp difference in levels of hydrocarbons present in the water UNIVERSITY OF IBADAN LIBRARY ' .578 systems during the different seasons of the year. All samples that gave high values were collected during the 1984 wet season, that is: Lever Brothers' Discharge (845) - 11.40 mg/1 L^_;s .Tarbour North oi NXPC facility (OS 7) 7.60 Asagjba (Ethiope river) (134) 30.10 Oleyua Creek/Benin river confluence (838). - • 13.90 Ogharife field effluent canal (0-2>. - 16.40 Upcrani discharge (831) - 17.50 ibenuchi (Okapi creek) (372) . - 7.20 ■ a.i ma/Patani floodplain (803) - 17.60 Elele Alimini (236) 70.70 Bakana (807) 42.20 Cross river floodplain (805) - . 6.90 This may be due to the flushing of hydrocarbons accumnulated on.lpnd through run off and storm water into the river systems during the wet season, which - . « may completely be absent during the dry season. There may also be a re-suspension of petroleum hydrocarbons in the water column due to mixing. UNIVERSITY OF IBADAN LIBRARY 379 The histogram of the mean hydrocarbon levels by t« * . IR in the different river systems is presented in Figure 34 below. / * A closer study of the hydrocarbon levels for discernible trends brought out a picture of a distri­ bution which is more of activity-related than water- type related. It is also difficult to use the water- type for explaining the observed hydrocarbon levels because the ’black-water’ rivers (acidic with low' conductivity, total adkalinity and high organic matter - RPI (1985) are all within the oil producing zone of the Niger Delta. In all the river systems sampled, high hydrocarbon levels were found in areas of known industrial activities such as Lever Brothers’ discharge point (845) - 11.40mg/l, Lagos Harbour near the NNPC Oil facility (087) - 7.60mg/l. Areas of known oil pollution, such as the Upomani discharge (831) - 17.50, ng/1, Chanomi creek (833) - 9.60mg/l, Okpari creek - Otorogu swamp (points A - F, Table 43) - 3.95 - 10.50 r.g/1. Other activity related points with high hydro­ carbon levels were found "close to oil fields and UNIVERSITY OF IBADAN LIBRARY 380 refineries, these include Onosi near Ebocha (013) - 5.00mg/l, Enwhe flow station (035) - 3.60mg/l, Okrika refinery Jetty (018) - 2.40mg/l; Agip slot (023) - 2.70mg/l and Kaduna refinery effluent channel (141 A and B) - 9.90 and 6.50mg/l. Some points where high hydrocarbon levels were recorded have no oil installations located within vicinity. Such points are Elele Alimini (236) 70.70mg/l Ahoada (022) 38.90 " Bakana (807) 42.20 " Aba (806) 10.10 ". All these points were located near towns. The results clearly implicated human settlements as one of the main sources of hydrocarbon pollution of the aquatic environment. Possible sources of hydrocarbons in urban river waters include, disposal of crank case oil and lubricants, accidental or intentional discharge of fuel oils and sewage . . . UNIVERSITY OF IBADAN LIBRARY FIG 34: MEAN LEVEL OF PETROLEUM IN WATER OF LAG 0 5 AND'NI GER DELTA BY RIVER SYSTEM (mg/t). MEAN HYDROCARBON CONCENTRATION UNIVERSITY OF IBADAN LIBRARY TABLE 46: PETROLEUM HYDROCARBON LEVELS BY GC IN SOME WATER SYSTEMS COMPARED WITH NIGERIA WATER SYSTEM • Oil-Concentration Location GC (pg /1) Reference Baltic sea • 8-150 Zsolany (1973) The North Brittany' Coast, France 240 ■ Law, R.J.(1978a) Gulf of Mexico Surface 60-160 Kennicutt et al. Bottom 61- 116 (1981) Bedford Basin Nova Scotia 1 . 6- 9.3 Keizer et al., (1977) Corton (unprotected Blackman and Beach) .19-370 Law (1981) North Harbour Lower Stoft protec­ 3,9-4 700 ted Beach Blackman and Law, (1981) ■ Off Coast of France 46-137 English Channel, France 1.1-74 Law (1978) Lagos and Lekki Lagoons, Nigeria 3-272 This Study Niger Delta, Nigeria 0.1-3356 This Study Kaduna river, Nigeria 0.07-0.11 This Study UNIVERSITY OF IBADAN LIBRARY 383 Gas chromatographic values of petroleum hydro- carl n levels.in water have been reported by many aut: rs. The results of this work clearly point at •c ue main, fact, that most of the river* systems in the M ger Delta and Lagos and Lekki Lagoons are either contaminated (.— 10Jlg/l) o'r'polluted lmg/1)255. This fact is brought out clearly when *the GC values for the samples in Tables 44.1-12 are compared with values in Table 46. The GC values for the hydrocarbon levels found in the river systems ranged between l.OOpg/1 - Nana creek (834) - .0. lp.g/1, TForcados estuary east of Terminal (860) - 0.2pg-/l and Bodo creek (121) - 0.5pg/l and Upomani discharge (831) - 3,3S6pg/l with 'an overall -average value of 179pg/r. • These values are- viewed alongside what have been reported from other parts of the world from inland waterways, coastal waters and the oil transport routes as shown in Table 46. 4.5 SEDIMENT - ' . The results of sediments analysis for petroleum hydrocarbons by gravimetry for the Lagos and Niger . UNIVERSITY OF IBADAN LIBRARY 584 \ Delta area are shown in Tables 47 and 4Sr The para­ meters determined include the moisture content, the sample weight conversion ratio, total .organic ae xtract,- aliphatic, aromatic and tota' l hydro, carbon. concentrations and the lithology of the samples. ' k*" • 4.5.1 LAGOS AND LEKKI LAGOONS . Seven points were sampled around the Lagos-Lekki Lagoons in the 1984 wet season. 'The percentage moisture for the samples varied from 17.81 (North of NNPC loading facility - 087) which was a,fine sand to 79.2% - Iwopin~(856) a mud sample (Table 47). The total organic extract (T^E) gave- a range of concentra tions from 73.01pgg ̂ (087) to- 1153.70pgg ̂ (Lagos Harbour at Lever Brothers' Discharge -•-845) on dry weight basis with a mean value of 350.09pgg \ Other results for the aliphatic, aromatic and the total hydrocarbons (THC) are as follows with the -mean given after the.range in parenthesis, 27.99-316.64 (112.29) 7. 75-243. 57 (54.56), and 4 8.67-560:21 (166.8.5) pgg-1 dry weight respectively. UNIVERSITY OF IBADAN LIBRARY The highest concentration of total■hydrocarbon (THC) was from. Lever Brothers' discharge point (845) - S60.21pgg while'a point north of NNPC loading facility (087) recorded the lowest THC level - 48.67 pgg . Iwopin (856), which may be regarded' as a pristine area in terms of petroleum activity on the Lekki Lagoon had 53.4Spgg ^. 4.5.2 BE.NIN RIVER SYSTEM Nine samples were analyzed for petroleum hydro­ carbons in 1984 wet season. The results-of the moisture content, total organic extract,-aliphatic, aromatic and total hydrocarbons were 17-.5 - 61.61, 43.17 - 317.08 (161.65), 8.49 - 183.69 (60. 57)', 2.58 - 75.36 (19.-94)' and 12.13 - 259.05 (80. 52) pgg-1 dry weight respectively. Ogharife field effluent canal - (0-2) had the highest level of THC - 259.05pgg 1 and Benin City (Tkpoba River) had the lowest THC - 12.13 pgg ' Asagba (134) - 110. 29pgg , Dudu Town (837) 102.60pgg \ and Olagua creek (838) - 176.08pgg~^. UNIVERSITY OF IBADAN LIBRARY t 5S5 4 .5* 3 ESCRAVOS RIVER SYSTEM Six samples were analyzed in 1984 season with the results for moisture content, TOE, aliphatic, aromatic' and THC as 26.2 - 75.01, 28.34 - 919.10 (284.07), 10. 80 - 11-7.37 (40.54), 2.70 - 60. 71 (19.19) and 13.50 - 178.08 '(59> 73) pgg ̂ respectively. Escravos terminal (054) recorded the highest value for THC and Upomani discharge (831) recorded the lowest• —- 13.50pgg a 4'. 5.4 FOKCADOS - WARRI RIVER SYSTEM Sixteen samples were analyzed in 1984 wet season. The moisture content, TOE, Aliphatic, Aromatic and THC values are 20. 4 - 6 8.9°*, 4 7.66 - 5 89.32 (295.15); .10.49 - 237.83 (1-27.10), 2.41 - 176.7 (63. 22) and 13.11 - 384.71 (190.52) pgg \ respectively. The highest THC level was in Obotebe (865) on Forcados river and the lowest level was in Patani (040). All samples except 4 - Patani '(040), upstream of Penfold Island (049), Agbarho (052) and Chanomi creek below mouth of Oyeye creek (351) recorded values above iOOpgg ̂ dry weight of THC. UNIVERSITY OF IBADAN LIBRARY 3S7 4.5.5 RAMOS RIVER SYSTEM Five points were sampled with -the results for the moisture, content, TOE, Aliphatic Aromatic and THC as follows 25.3 -= 5 8.61, 98. 29 - 641.25 (409.48), 7.95 - 315.67 (171.55), 0.49.- 160.31 (119.03), 8.44 - 564.05 (302.58) pgg ̂ dry weight. The highest THC value was recorded at Orughene creek (8.70) - 564.05pgg ̂, while Muri creek (.871) recorded the lowest value of 8.44 ^gg -1 •' • 4.5.6 NUN-EKOLE - BRASS RIVER.SYSTEM The range-and mean values for the moisture content, TOE, Aliphatic, Aromatic and THC of the five samples analyzed are 20.7 - 54.5%, '62.73 - 352.79 (173.03), 6.17 - 159.89 (65.03), 0.15 - 8].SO (28.03) and 6.32 - 241.67 (93.06) pgg ' dry weight. The highest THC level was recorded at Diebu creek (043) - 241.69pgg and the lowest at Elpe creek (281) — 6.32 pgg ^. 4;5.7 ORASHI RIVER SYSTEM Th.e fourteen samples analyzed gave the following results., moisture content - 17.4-58.0%, TOE - 11.91- 771.40 (266.97) jjgg"1, Aliphatic - 1.60-135.69 (38.17) UNIVERSITY OF IBADAN LIBRARY 3SS / ' pgg \ Aromatic - 0.54-91.90- (15.50) pgg ̂ and THC. 2.14 - 227.59 (55.67) pgg ^. The highest value for THC was recorded for Degema (.021) - 227.59pgg ^, while 6moku creek (824) recorded the lowest THC level'of 2.14pgg Oguta Pontoon crossing-(014) and Lake Oguta (south shore) (0.16)', recorded 107.72 and 103.68 pgg ̂ THC respectively. 4.5.8 BONNY - NEW CALABAR RIVER SYSTEM Seven samples were collected and the analysis gave the following results;' moisture content - 18.2 53.3$, TOE - 78.86-1283.44 (369.69), Aliphatic 5.46- 92.31 (36.86), Aromatic - 0.97-36.27 (17.45) and THC - 6.43-128.58 (54.31) pgg ^ . Bakana . (upstr.earn) (807) recorded the highest value - 128.58pgg ̂ while the lowest was. recorded at Alaoc-ha (810) - 6.45 pgg'\. 4.5.9 IMP RIVER SYSTEM The results for. the moisture, content, TOE, / * Aliphatic, Aromatic and THC are 18.*9-48.9$, 134.88- 3894.34 (1430.72), 5.56-117.84 (51.62), 0.23-61.78 (23.60) and 5.79-179.62 (75.22) pgg ̂ respectively. UNIVERSITY OF IBADAN LIBRARY 5S9 The highest THC value was recorded at Kono waterside (128) - 179.62pgg . Otamiri (817) recorded the lowest - 5.79pgg 1.- 4 .5.10 CROSS RIVER - CALABAR,RIVER SYSTEM The moisture content, TOE, Aliphatic, Aromatic and THC results for the four samples analyzed are, 27.3-57.61, 54.91-154.00■ (105.59) , 8.21-37.80 (18.76), 1.75-4.61 (3.68), and 9.97-42.00 (22.44) pgg-1 respectively. Calabar new port., complext (827) recorded the highest THC, wTith Parrot Island • (811)' recording the lowest value for THC. 4.5.!1 KADUNA RIVER SYSTEM The results of the 3 samples from Kaduna for the moisture content, TOE, Aliphatic, Aromatic and THC are 21.2-34.1%, 14.86-232.90 (106.79), 7.43-112.65 (52.13), 1.49-58.86 (25.15) and 8.92-171.51 (77.26) pgg"1 respectively. The highest THC value was recorded at the Kaduna refinery effluent channel downstream, (141A) - 171.51 pgg ^. Doka park in Kaduna on Kaduna river (843) recorded the lowest THC level. UNIVERSITY OF IBADAN LIBRARY TABLE 47 : .GRAVIMETRIC DATA Of SEDIMENT SAMPLES AROUND LAGOS AND NIGER DELTA AREA OF NIGERIA- WET SEASON (AUGUST-NOVEMBER 1984) (pg'g"1 DRY WEIGHT) • SN ' Statii on Lithology % Wet Wt. Dry Wt. of TOE Aliphatic Aromatic THCCode of Sample Moisture Dry Wt. Sample (g) pg g-1 H'g S-1 . pg g-1 pg g-1 1. LAGOS - LEKKI LAGOONS . 1 086 MUD 25.8 ' 1.22 74.30 119.79 . 51.15 • 43.07 94.22 2 087 FINE SAND 17.8 1.35 82.18 73.01. 27.99 ■ 20.69 • 48.67. 3' 845 MUD 58.9 2.44 41.06 1153.70 . 316.64 . '243.57 560.21 4 847 MUD 66.1 2.94 34.05 202.64 .132.31 26.43' 158.74 5. ,851 MUD 42.9 , 1.75 . 51.63 154.94 127.82 7.75 . 135.57 6 ' 856' MUD ■' • 73.2 4.82 18.70 374.37 • 42.79' 10.70 , 53.48 7 857 MUD 77.2 4.39 18:54 372.17 87.33 / 29.74 117.07 / X ' 350.09 112.29 54.56 • 166.85 ' . SD ±154.38 ' ±41.24 ±33.69 ±73.08 ' R(. 73.01 27.99 7.75 48.67 -1153.70 -316.64 -243.57 -560.21 2. BENIN ' * * 8 ■057 MUD 30.7 1.44 69.50 43;17 11.51 ■ 2.88 14.39 9 134 MUD 28.4 1.41 72.54 317.08 ' 104.77 5.51 110.29 • l.0 311 COARSE SAND 17.5 1.21 85.50 77,27 8.49 ^3.64 12.13 11 347 MUD 61.5 2.59 38.79 103.11 18.04 '2.58 20.62 12 835 MUD 31.3 ■ 1.46 68.78 189.00 11.81 4.27 16.08 13 837 MUD 61.6 2.621 38.93 128.25 ' 32.08 • 20.52 - 102.60 . UNIVERSITY OF IBADAN LIBRARY \ TABLE, 47 (contd,) Station Lithology % Wet Wt. Dry Wt. of TOE Aliphatic Aromatic THC Code of Sample Moisture Dry Wt. Sample (g) . pg.g-1 pg g_1 pg g"1 . pg g_1 ' 14 m MUD 50.6 2.02 49.39 252,64 114'. 05 .62.03 176.08 15 ■0-1 COAR'SE SAND 25.6 1.34 74.66 60.91 10.72 2.68 13.40 16 0-2 'FINE SAND 21.2 1.27 78.86 283.43 i83.69 75.36 259.05 X • 161.65 ' 60.57 ■ 19.94 80.52 SD ±30.43 ±19.47 . ±8.09 ±27.43 • R 43.17' 8.49 ' 2.58 12.13 • . ' -317.08 -183.69 -75.36 -259.05 3.. ESCRAVOS • • 17 054 MUD 53.2" 2.14 24.71 • 429.01 117.37 60.71 178.08 18 ' 055 MUD 33.8 1.51 67.46 . ; 919.10 18.12 4.50- 22.62 19 360 i ;mud 75.0 ’ 4.00 '25.11 ! 123.46 23,90 15.93 39 .83' 20 362 MUD 59.4 2.46 • 40.60 141.87 57.39 22.46 79.85 21 831 MUD •=> 26.2 1.36 74.11'- 28.34 10.80 • 2.70 13.50 22 839 \ MUD 65.9 2.94 35.34 62.64 15.66 8.83 24.49 . \ X . 284.07 40.54 19.19- 59.73* SD ±148.46 ±17.76 ±9.67 ±27.43 •R 28.34- ■ 10.80 2.70 13.50 * -919.10 -117.37 -^0.71 -178.08 ii UNIVERSITY OF IBADAN LIBRARY 392 TABLE 47 (contd.) SN Station Lithology * Wet Wt. Dry Wt. of TOE Aliphatic Aromatic THCCode of Sample Moisture. Dry Wt. Sample (g) pg.g-1 • - pg g-1 Pg g-1 P g g -1 4. FORCADOS- WAR11 • 23 . 040 , , Olay 25.4 . 1.34 76.26 * 65.56 10.49 2.62 13.11 24 ■» 049 c l a y ' 41.5 1.71 58 ;52 ’ . 73.92 21.96 16.84 38.81 25 050 MUD 62.4 '2.66 33.90 ’ • 383.48. 200.30 •176.70 377.00 26 052 ■ FINE■SAND 20.4 . 1.26 80.55 86.90 . 17.31 2.41 19.72 . 27 053 MUD 36.6 1.58 63.4.6 . 236.37 211.16 11.03 ' 222.19 28 351 MUD 58.0 2.38 41.96 47.66 33.36 14.30 47.66 29 ’ 352 . MUD 68.9 3.22. . ,31.07 428.76' 182.19 122.53 304'. 72 30 • 353 MUD 42.5 1.74 57.59 451.47 69.46 52.09 121.55' 31 372 FINE SAND 21.8 1.28 79.92’ . 589.32 147.64 ' 27.53 175.17 32 858 MUD 67.9 3.12 29.08 481.48 237.83 113.76 351.59 33' 860 MUD ■ 56.4 1.87 35.37 267.65 167.46 54.34 221.80 .34 862 . MUD 43.5 . 1.77...- ' 56.56 256.58 157.07 75.30 232.37 35 863 MUD 62.0 2.63 38.05 446.84 178.28 55.20 233.48 36 864 CLAY 34.2 1.59 66.07 290.82' 112.51 \80.52 193.03 ‘ 37 ,865 CLAY 36.7 1,58 63.64 415.71 220.00 164.71 384.71 38 866 MUD 39.6 1,65 60.67 198.90' 66.59 41.65 108.24 X 295,15 127.10 63.22 190.32 , ' • SD ±169,33 ±79,42 ±55,58 ±124.60 * * •H 47.60 '10.49 2/41 13.LI ' -589.32 -237.. 83 -176.7 -384.71 UNIVERSITY OF IBADAN LIBRARY --- ------------- —---- --------- - r~ 3.) 3 TABLE 47 (ccntd.). Station Lithology % Wet Wt. Dry Wt. of TOE Aliphatic Aromatic THCSN Code of Sample Moisture Dry Wt. Sample (g) pg g_1 ' Pg g-1 pg g-1 • pg g-1 5: RAMOS • 39 . 038 CLAY 52.7 ' 2.11 '45.32 446.33.. 225.66 • 108.61 334.27 40 382 * 'MUD 53.-2 2.14 46.86 512.12 117.11 121.63 293.74 41 869 CLAY ' '25.3 • 1.34 74.86 349.42 .191.37 . 116.03 • 307.40 42 870 • MUD 58.6 . 2.41 41.45 641.25 315.67 248.38 ' 564.05 43 • 871 MUD ' 57.5 2.35 42.68 98.29 7.95 0.49. 8.44 ' / X 409.48 171.55 119.03 ' 302.58 * SD ±108.59 ±61.54 ±31.96 ±111.12 R 98 v29 7.95 0.4S 8.44 6. NUN-EKOLE-BRASS -641.25 -315.67 -160.31 -564.05 44 036 FINE SAND 2C.7 1.26 79.27 62.73 6.55 2.52 • 9.07 45 0 43 . , CLAY 46.3 1.86 : 53.79 332.79 159.89 81.80 241.69 281 MUD 54.5 2.82 35.51 75.98 ■ 6.17 0.15 6.32 47. 872 CLAY 36.4 1.57 63.93 172.08 86.04 o.26 92.30 48 873 CLAY 41.5 1.71 58.67_ 221.59 66.48 49.43 115.91 X 173,03 •65.03 28.03- 93.06 . .SD ±54.01 ±30.74 ±16.33 ±47.07 R 62.73 6,17 0.15 6.32 ' -• . -332.79 -159.89 -18.80 -241.69 • / 3 * - UNIVERSITY OF IBADAN LIBRARY 394 TABLE . 47 (contd.) ‘ SN Station Lithology % Wet Wt. Dry Wt. of TOE Aliphatic Aromatii THC • ________ Code ■ of Sample Moisture Dry Wt. _ Sample (g) yig g-1. g-l • g-l g-j ,7. ORASKI 4 .49 ' 012 COARSE SAND 17.4^ 1.21 83.97 • 11.91 ’ 8.34 1.19 9.53 50 013 MUD. . 30.5 .1.41 •59.20 48.74 16.74 13.36 30.10 51 014 CLAY • 25.4 1.34 75.20 200.81 '95.75 . ' 11.97 107.72 52 016 FINE SAND . ' 22.2 r.29 78.84 • 279.04 84.65 19.68 103.68 53 021 MUD 57.9 1.38 42.03 • ; 452-.02 135.69 91.90- 227.59 '54 035 FINE SAND 30.6 1.44 ,72.811 218.37 12.36 1.37 13.23 55 250 COARSE SAND ,2.1.9 1.28 78^25 293.94 10.22 2.56 12.78 56 251 COARSE SAND sL8,2 1.22 83.84 i 250.48 18.35 • 10.58 •23.78 57 252 MUD 58,0 2.38 42.11 451.24 42.50 19.87 62.37 58 262 ■COARSE SAND . 19.2 1.24 81.80 365.53 31.79 17.12 ' .91 59 801 CLAY 18.2 1.22. _ ; 83.92 47.66 19.53 7.38 26.91 60" 802 CLAY 24.9 1.33 75.45 83.02’ • ■ 44.58 16.63 61.21 6i • 821_ MUD 43.0 1.75 57.04 771.40 12.27 \ 3.51 15.78 62 824 FINE SAND 20.4 1.26 79.57 263.94 1.60 0.54 2.14 X 266.97 • 38..1-7 15.50 53.66 * • ■ 'SD ±54.25 ±9.58 ±6.53 ±15.10 R 11.91 1.60 0.54 .2.14 • -771.40 -135.690 -91.90 -227.59 . / • / • ’ \ 'i / ; k \ ' UNIVERSITY OF IBADAN LIBRARY 395 TABLE 47 (contd.) cm Station Lithology % Wet Wt. Dry Wt. of - TOE Aliphatic Aromatic THCCode of Sample Moisture Dry Wt. Sample (g) Mg g-1 PS g-1 P S g_1 p s g_1 g; BONNY - NEW CALABAR > 63 * ’ 020 COARSE SAND 18.2 1.22 81.'99 •110.98 13.42 • 7.32 20.74 64 121 • MUD 53.3 2.73 36.67 • 300.00 16.36 10.91 27.27 65 2339 MUD. 44.5 1.80 55.39 235.98 55.77 35.03 90.80 66 807 MUD 46.7 1.88 55.32- 1283.44 •92.31 36.27 128.58 '67 808 MUD 36.6 1.58 6,3.40 78.86 37.85 14.20 52 ..05 '• 68 810 SAKD/PEBBLES 19.7 1.25 ■ . 81.39 208.88 5.46 0.97 6 i 43 ' X 369.69 36.86 ■ 17.45 54. 31 • sd' ±200.76 ±14.48 ±5.88 ±20.36 R 78.86 5.46 0.97 6.43 -1283.4,4 -92.31 -36.27 -128.58 9'. IMO 69 . ■ 128 MUD 48.9 1.96 51.41 3894.34. 117.-84 61.78 179.62 70 813 • COARSE SAND 20.4 1.26 79 i 87 262.94 31.47 8.78 40.25 71 817 FINE SAND ' 18.9 1.23 81.55 134.88 5.56 0.23 5.79 X 1430.72 51.62 23.60 75.22 • sb ±1253.15 ±37.43 ±20.52 ±57.94, . R 134.88 5.56 0.23/' 5.79 * ' -3894.34 117.84 -61.78 -179,62 UNIVERSITY OF IBADAN LIBRARY 396 i . TABLE 47 (contd,) SN Station , Lithology % Wet Wt. Dry Wt., of TOE Aliphatic Aromatic THCCode of Sample Moisture Dry Wt. 'Sample (g) MS 8_1 MS 8-1 y & s-1 MS 8_1 10. CROSS RIVER - CALABAR ‘ 72 071 CLAY 27.3" 1.38 .72.84 54.91 • 20.70 4.61 25.31 73 811 MUD 57.6 2.36 42.54 70.53 8.21 . 1.75 9.97 f 74 812 ’ MUD 37'. 5 ' 1.60 62.97 .142.93 8.33 4.14 12.47 75 827 MUD 54.6 2.20 45.45 . 154.00 37.80 4.20 42.00 / X 105.59 18.78 3.63 ' 22'. 44 SD ±24.77 ±7.40 ±0.72 ±8.01 > R r 54.91 8.21 1.75 9.97 -154.00 -37.80 -4.61 -42.00 11. KADUNA i 76 141A . CLAY 21.2 • 1.27 79.03 232.90 112.65 58.86 171.51 77 843 MUD 34.1 1.52 67.32 ‘ 14.86 . 7.43 1.49 8.92 78 . 844 ' MUD 21.4 1.27 97.38 72.60 36.30 15,. 04 51.34 N ^ X 106.79 52.13 25N.13 77.26 ■ ' SD ±72.68 ‘±35.Q7 ±19.12 * ±54.20 • R. 14.86 7.43 1.49 8.92 I - -232.90 - -112.65 -58.86 -171.51* \ UNIVERSITY OF IBADAN LIBRARY 39 7 In 1985 (dry season) sampling, the number of sai-rling points were reduced in all the river systems. The results of the gravimetric determinations are ffcoiin Table 48. • • 4.6 . i LAGOS AND LSKKI. LAGOONS- Only 3 points were sampled and the results for ncisture content, TOE, Aliphatic, Aromatic and THC are 59.0-70.5%, 58.99-127.53 (91.49)', 22.51-40.60 (29 . 78), 15.55-20.01 (17.19) and 42.51-54.13 (46.96) pgg"1 eight respectively. All the points- recorded lower levels of THC Than the levels recorded, during the 1984 vet season. However, the Lever Brothers’ discharge point still maintains the.highest level of total . , hydrocarbon. • 4.6.2 BENIN RIVER SYSTEM . . * Only Benin City (Ikpoba river) was sampled in Benin river system. The level of THC increased "slightly from 12.13pgg 1 in 1984 to 17.96jjgg 1 in 1985. v UNIVERSITY OF IBADAN LIBRARY 4.6.5 ESCRAYOS RIVER SYSTEM Four points were sampled, with the results for neisture content, TOE, Aliphatic, Aromatic and TKC as 5c.~ - S 5 . , 2 i 7.S3-525.56 (264.98), 46.17-195.49 [S3. S4 j , 5.73-90.23 (39.96) and’ 51.91-285 . 72 (125.80) pgg * respectively. The values are higher than those obtained during the 1984 wet season. 4.6.4 F0RCAD0S - WARRI RIVER SYSTEM Ten points were sampled with the following - results moisture content - 19.6-69.71, TOE -'23.87-750.62 (lcS.64) pgg 1, Aliphatic: 8.04-42.49 (20.71) pgg-1, Aromatic: 4.42-13. 73 (9.85) pgg 1 and THC: 13.50-52.73 30.56) pgg 1. When the values are compared with the 19S4 values there is no discernible trend because some of the points recorded higher THC values over the 1984, examples are Patani (040), Penfold Island (upstream) (049), and Agharho (052) with THC levels of 13.11, 3>. 81 and 19.72 pgg - X' respectively for ’ 1984 . In 1985 the THC levels for these three points moved up to 16.19 33.34 and 52.73 pgg 1 respectively. All the other poin recorded lower THC levels for 1985. UNIVERSITY OF IBADAN LIBRARY 399 .4.6.5 ORAHSI RIVER SYSTEM : • • Six samples were collected and analyzed, with the results as follows: moisture content: 21.8-58.61, TOE: 18.46-116.52 (42.72) jagg \ Aliphatic: 11.66-54.99 (20.80) pgg \ Aromatic: 0.64-22.26 (9.46) pgg ''"and THC: 12.30 - 7 7.. 25 (30.26) pgg ^ . The mean values for all the parameters are lower than those recorded for the 1984 samples. 4.6.6 BONNY - NEW CALABAR RIVER SYSTEM The results of the five samples collected for the 1985 seasons are moisture content: 50.7-74.6-0 , TOE: 68.92-147.13 (110.45), Aliphatic: 15.59-125.35 (60.98), Aromatic: 8.11-38.51 (19.10) and THC: 24.94-139.28 (80.07) pgg Most of the values are higher than the 1984 values. . • 4.6.7 CROSS RIVER - CALABAR RIVER SYSTEM Only two samples were analyzed in 1985. The results "are 19.8-23.1°& - moisture content, 49.81-.181.91 (1 15.86) pgg ̂ TOE, 6.50-18.68 (12.59) pgg ̂ Aliphatic, 2.60- 12.45 (7.53) pgg ̂ Aromatic and 9.10-33.13 (20.12)pgg * , THC. \ ( i UNIVERSITY OF IBADAN LIBRARY .400 TABLE 43: GRAVIMETRIC DATA OF SEDIMENT SAMPLES ARO'UND LAGOS AND NIGER DELTA AREAS OF NIGERIA (FEBRUARY 1985) (DRY WEIGHT BASIS) SN •Station Lithology % Wet Wt.* Dry Wt. of TOE Aliphatic Aromatic • THC Code of Sample . Moisture Dry Wt. Sample (g) pg g_1 Fg g-1 • pg.g-1 pg g_1 1. ■■ LAGOS-LEKKI LAGOONS • 1 845 MUD 70.5 3.39 29.56 87.96 . 40.60 13.53 ’ 54.132 851' MUD 39.0 _ 1.64 61.03 58.99 26.21 18.02 ' 44.24 3 '.857 MUD 60.0 2.50 39.99 127.53 22.51 20.01 42.51 / X - 91.49 29,78 17.19 46.96 _ • SD ±22.85 13.61 ±2.16 ±3.87 . Vj P- 58.99 22.51 . 13.53 42.51 j : • 12-7.53 -40.60 -20.01 -54.13 ' 2. BENIN ’ * 4 311 COARSE SAND 16.5 • 1.20 83.54 83.79 11.97 ' 5.99 17.96. 3. ESCRAVOS • .5 054 MUD 56.7 3.61 21.70 294.49 195.49 ■ ''90-23 285.726 055 MUD 86.7 3.48 6.65 .325.56 64.52 36.87 101.387 830 MUD 62.8 4.51 18.17 247.66 • 60.87 32.22 93.09 V 8 833 MUD 62.6 3.72 23:02 238.92 52.13 34.75 86.889 834 ‘ MUD 65.1 2.81 34.89 217.83 46.17 . 5.73 51.91 • X 264.98 83.84 39.96 123.80 SD ±21.55 ±29.86 .±16.90 •±46.76 • -R 217.83 . 46.17q 5.73 51.91 • • , -325.56 -195.49 -90.23 -•285.72 y • •‘P + UNIVERSITY OF IBADAN LIBRARY 401 TABLE.4 8 : ( c o n t d .) Station Lithology % Wet Wt. » Dry Wt. of TOE Aliphatic • Aromatic TKC Code of Sample Moisture Dry Wt. Sample (g) jig g-1 g-1 y ,g g-1 ^g g-1 4. FO.RCADOS - WARM * • ' 10 040 FINE SAND ‘ 32.1 '• 1.47 67.94 47.78 . 4.42 . 16.19 * 16.19 11 049 • CLAY ■ 32.7 1.49 67.48 28.16 22.23 ‘ 11.11 33.34 12 . 050 MUD 50.7 2.71 29 .-69 ; 114.52. 26.74 13.37 . 40.10 13 052 FINE SAND 19.6 1.24 80.43 -’ 53.57 42.49 10.24 • 52:73 14 ’ 053 MUD 60.8 .2.93 31.46 289.79 8.04 5.47 13.50 15 351 MUD .I" 6.3.3 3.65 23.87 ;• 92.17 13.73 7.49 21.22 16 353 MUD 69.7 5.43 15.74 730.62 19.06 12.71 31.77 17. 1 860Q \MUD 30.5 1.56 54.47 23.87 27.34 13.67 41.02 862 MUD 63.1 • 3.84 22.20 252.25 16.90 13.73 30.63 19 866 MUD 52.2 2.09 47.81 54.38 ■ . 18.83 6.28 25.10 • : X 168.64 20.71 \ 9.85 30.56 SD ±70168 ±3.45 ±0.93 ±3.92 R 23.87 8.04 42.49 13.50 5. ORASHI 730.62 42.49 -13 .73 -52.73 20 021 . MUD 58.6 2.413 41.480 26.52 12.05 9.64 21.70 21 ;.5o FINE SAND 21.8 1.274 * 78.310 33,20 14.05 8.94 22.99 22 252 CLAY 23.7 1.310 76.385 116.52 54.99 22.26 77.£5 23 801 • CLAMY4 22.0 1.282 78.045 18.46 11.66 0.64 12.30 UNIVERSITY OF IBADAN LIBRARY 402 , 4’ABLE 48 ( c o n t d . ) SN Station Lithology % Wet Wt. Dry Wt. of TOE AliphaticCode Aromatic THCof Sample .Moisture Dry Wt. Sample (g) PS g-1 Pg g"1 pg g-1 PS g-1 24 819 CLAY 44.2 1.791 55.878 24.25 14.00 6.24 20.24 25 ' 820 FINE SAND 22.5 1.290 77.590 • 37.38 ' 18.04 9.02 27.07 • x 42.72 20.80 9.46' 30.26 * SD . ±16.34 ±7.22 ±3.6Q ±10.83 ' R , * . 18.46 11.66 0.64 12.30-116.52 .-54.99 22.26 -77.25- 6. BONNY - NEW CALABAR 26 r 27 • 081 MUD 64.8 '2.842 35.172 • 136.48 ' 79.61 25.59' ' MUD 1G5.20020 74.6 ■ 3.930 / 25.460 147.13 125.93 • 13.93 139.28 28 • 121 MUD 50.7 2.028 49.332 ‘ 68.92 20.14 ' 8.11 28.25 29' 807 MUD 68.3 3.129 32.079 84.17 15.19 .9.35 24.94 30 808 ' MUD 68.9 3.211 31.161 115 .53 64.19 38.51 102.70 X 110.45 60.98 19.10 80.07 SD ±15.64 ±21.95 ±6.08 ±22.87 - - R 68.92 15.59 8.11 24.94 7.- CROSS RIVER - CALABAR -147.13 -125.35 \-38.51 -139.28 O * \079 COARSE SAND 19,8 1.247 80.302 ' 49.81 18.68 12.45 31.13 32 210 CLAY 23.1_ 1.300 76.960 ' 181.91 6.50 2.60 9.10 • f X .115.86 12.59 ' 7.53 20.12 • SD ±16.05 ±6.09 ±4.93 ±11.02 • , R 49.81 6.50 2.60 9.10 -181.91 -18.68 -12.43 .±01.13 \ UNIVERSITY OF IBADAN LIBRARY TABLE 48: ( c o n t a . ) SN Station Lithology % ' Wet Wt. Code Dry Wt. of of Sample ’ TOE Moisture Dry Wt. Aliphatic Aromatic "Sample (g) THCp g g-1 US g_1 p g g ~ \ P Z g_1 '8. ■ KADtfNA ■ ■ 3 . 3 141A ' CLAY i8.4 ' ' 1.225 81.662' . 67.35 . 19.59 ■ 14.70 34.29 34 141B . CLAY . 23.9 .1:314 76.190 173.25 53.81 6.56 60.38 * • X 120.30 36.70 10.63 47.34 SD ±53.0 ±17.11 ±4.07 ±13.05 • / R 67.35 " 19.59 6.56 34 ."29 . -173.25 ■ -53.81 -14.70 -60."38 ■ 35 Ag-1 FINE SAND 18.6 1.229 81.81̂ 47.670 32.00 . • ND 32.00 36 As-2 MUD ' 41.4 1.706 58.745 '297.900 17:02 6.81 23.83' UNIVERSITY OF IBADAN LIBRARY 4 0 4 4.6.S KADUNA • Only the Kaduna refinery effluent channel was s-mpied. The. downstream and upstream values for moisture content, TOE,- Alipahtic, Aromatic and TrlC are 18.4-23.9%, 67.35ri73.25 (120.30), 19.59.-53.81 (36.70), -6.56-14^70 (10.63) and 34.29-60.38 (47.34) yigg * respectively. 4-6.9 IBADAN ■ The two samples collected at Ibadan in Agodi Garden (Ogunpa) and Asejire gave the .following results for moisture content, TOE, Aliphatic., Aromatic and TKC ' - Agodi - 18.6%, 4 7i6 7, 32.00, ND and 32.00 pgg-1 Asejire - 41.4%, 297.90, 17.02, 6.81 and 23.83pgg_ respectively. • - . Agodi sediment was a fine sand while Asejire sediment was muddy. • . • ^ 4.-6.10 UTOROGU SWAMP AND OKPARI RIVER The Utorogu swamp and Okpari river were sampled thrice (Oct. - Nov. 1984,'Jan.-Feb., 1985 and June-July 1985). The results of the gravimetric method for the UNIVERSITY OF IBADAN LIBRARY t i 4 0 5 ' ‘ x moisture content, Total organic extract [TOE, Aliphatic, Aromatic and Total hydrocarbon (TilC) are given in Tables 49-5.1 for the three ’sampling periods. The range and the mean (in parethesis) for these parameters for the 1984 samples are 22.8-85.0$, 89.12- 805.00 (277.94), 21.22-249.92 (105.98), 4.21-122.15 (32.44) and 29.72-344.09 (138.42)_pgg ̂ dry weight, respectively. The highest THC values were recorded at points B, D (swamp), G (transect), R (transect),'0 (transect), K (transect) and T. The dry season samples (Jan.-Feb. 1985) gave 18.1-74.7%, 17.391-491.02 (94:83), 2.98-96.98 (27.17), 1.25-31.62 -(11.04) and 5.47-1-22.76,(38. 22) pgg-1 - respectively for same parameter stated above.• The last set of- samples collected during the -early wet season in 1985 (June-Juiy) recorded the following ■ values: 16.9-73.7%, 18.35-283.21 (91.46), 10.23-11.73 "(32.4 6), 1.42-66.64 (10.77), and 13.37-1 77.37 (43. 23) pgg ̂ respectively. • The 1984 samples recorded the highest values for all the parameters listed above. The levels came down. UNIVERSITY OF IBADAN LIBRARY 'll M) \ TABLE 49: • GRAVIMETRIC DATA OF SEDIMENT SAMPLES AT UTOROGU "SWAMP AND OKPARI RIVER IN BENDEL STATE .OF NIGERIA (OCTOBER 1984) CN Station Lithology % Wet Wt. Dry Wt. of TOE Aliphatic Aromatic THCCode of Sample Moisture Dry Wt. Sample (g) jig g-1 ‘ pg S_1 pg g-1 pg g-1 •IMPACTED SWAMP i B ■ MUD 47.0 1.887 53.072 354.64 133.78 80.27 214.05 ■ou D FINE SAND 28.9 1.405 48.924 419.02 . 122.64 30.66 153.30 3 E MUD 42.1 1.727 57.970 ‘106.95 43.13 30.85 73.98 4- G-l • MUD 50.4 2.018 49'. 722 187.04 57.12 15.83. 72.95 5. G-2 1 1 MUU 49.4 . . * 1.976 50.771 . _• 171.36- 50/28 ■ 11.49 61.77 6 * G-3 MUD • 63.2 2.718 36,881 • • 197.61 81.34. •23.08 104.42 7 G-4 FINE SAND 25.5 1.342 74.660 220.55 139.30 38.38 177.68 • X 236.74 '89.66 32.94 122.59 UPSTREAM . R . 106.95 . 43.13 11.83 61.77 8 ’ -419.02 -139.30 -80.27R-l FINE SAND -214.05 '28.6 1.399 / 71.633 • 117.26 103.30 5 9.35 11.2.651 R-2 MUD 23.4 1.305 ■. / 76.773 274.54 157.61 4.21 161.82 10 R-3 MUD 64.5 2.821 35.553 228.13 101.26 5.67 106.93 "I 206.64 120.72 6.41 127.13 DOWNSTREAM R 117.26 101.26 4.21 106.93 • 11 0-1 MUD 65.7 . 2.915 34.411 S3!:86 157.61 9.34 161.82 . 249.92 83.31 333.23-12 0-2 MUD . 5 6 . 3 . 2.290 43.705 796.25 221.94 122.15 344.09 13 N . MUD 31.5 1.459 68.530 245.11 61.29 8.36 69.65 I UNIVERSITY OF IBADAN LIBR RY 40 7 \ TABLE 49; (contd.) SN .Station Lithology % Wet Wt. Dry Wt. of TOE A.liphatic Aromatic THCCode of Sample Moisture Dry Wt. Sample (g) pg g_1 "Pg g"1 Pg g-1 y g g-1 ' 14 .V MUD 47.4 1.902 52.827 141.97 37.86 15.17 53.03 15 K-l ' MUD 76.5 4.252 23.565 89.12 21.22 8.50 29.72 16 K-3 MUD 83.0 5.871 13.750 323.73 167.27 50.81 218.08 17 ' .T FINE SAND 22.8 1.295 77.264 171.38 98.36 20.15 , 118.51 18 ' .U ■ ■ FINE SA1JD 26.8. ■ '1 1.365 73.299 • • 153.21 • 60.03 ■ 25.73 85.76 X • 340.72 114.74. 41.77 156.51 R . 89.12 21.22 8.36 29.72 * ‘ , 805.00 249.92 122.15 344.09 . / / UNIVERSITY OF IBADAN LIBRARY 408 TABLE 30; GRAVIMETRIC DATA OF SEDIMENT SAMPLES AT UTORCGU SWAMP AND OK PAR 1 RIVER IN BF.NDEL STATE OF NIGERIA '(JANUARY - FEBRUARY 1985~)~* SN Station Lithology % Wet Wt. Code Dry Wt. of TOEof Sample .Moisture Aliphatic Dry Wt. Aromatic THCSample (g) ' pg g_1IMPACTED SWAMP pg g-1 pg g-1 >'g g-1 1 B1 CLAY • 39.0 1.642 '60.746 151.45 23.05 1.65 24.69 2 '■ B2 CLAY 19:0 1.237 80.065 . 138.64 '8,74' 1.25 9.99 3 C CLAY 18.6 1.228 ; 81,463 491.02 96.98 25.78 . 122.76 4 ■ D • « MUD 55.-2 2.237 44.611 126-.90 38.11 6.73 '44.83 5 E CLAY 30.1 1.430 69.963 , ' 57.17 24.30 •■17.17 41.45 6 E2. * CLAY -■ 23.5 1.31 . 75.655 51.55 26.44 21.15 47.59 „ 7 F MUD •74.7 3.953 ■ 25.298 101.15 59.29 31.63 90.92 ' X 159.70 39.56 15.05 54.60 . / R 51.55- 8.73 1.25 9.99 •-491.62 -96.98 ' 31.62 -122.76UPSTREAM 8 R-i MUD ' 68.9 3.274 . 30.300 52.81 13.20. 3.30 16.50 ’ 9 R-2 FINE SAND 22.0 1.282 78.059 £2.28 32.03 5.12 37.15 X ' 47.55 22.62 4.21 26.83 .— - ’ R 42.28 13.20 3.30 16.50 -52.81 -32.03 -5.12 -37.15 \ \ . / UNIVERSITY OF IBADAN LIBRARY 409 TABLE 50 ( c o n t d . ) SN Station Lithology Z Wet Wt. Dry Wt. of TOE Aliphatic Aromatic THCCode of Sample Moisture Dry Wt. Sample (g)’ g-1 >*g g-1 pg g-1 ' >g g-1 DOWNSTREAM • . 10 0-1 MUD 59.7 .2.483 40.250 17.39 2.98‘ 2.48 5.47 11 0-2 ' FINE SAND 18.1 1.221 ■ 8,1.961 29.28 15.86 6.34 22.20 12 0-3 FINE SAND 29.4 1.416 70.658 . , 35.38 . 16.98 ■ 14.15 31.15 13 N FINE SAND 20.4 1.256 79.605 48.59 16.33 ■ 12.56 • 28.89. 14' K-2 FINE SANtf 24.1 1.318 75.858 52.73,. 15.82 . 10.55 26.37 15 T " .* FINE SAND 22-. 1 1.429 51.461 75.79 17.49 5.83 23'. 32 , V X 43.19 44.24 8.65 . 22.90 RANGE 17.39 2.98' 2.48 5.47 * -75.79 -17.49 -14.15 -31.14 I \ \ \ . I 1i .V. UNIVERSITY OF IBADAN LIBRARY • I 410 TABLE 51: GRAVIMETRIC DATA OF SEDIMENT SAMPLES AT UTOROGU SWAMP AND ' OKPARI RIVER IN BENDEL STATE OF NIGERIA (JUNE-JULY 1985) • Station Lithology % Wet Wt. Dry Wt. of •TOE Aliphatic Aromatic' THC . Code of Sample Moisture Dry Wt. Sample (g) pg g-1 pg g"1 pg g"1 pg g_1 IMPACTED SWAMP 1 A-l ‘MUD 69.3 3.255 30.738 126.88 53.68 17.89 71.57 \I 2 B FINE SAND 65.3 2.873 ■ 34.869 237.28 •110.73 66.64 177.37 3 C-2 • MUD 73.7 3.805 26.278 . 26.64. 33. 42 ■ 5.39 38.81 4 C-3 FINE SANS 54.2 2.183 45.812 74.22 41.84 8.37 • 50.21 • 5 _ D MUD 71.8 3.545 28.209 42.58. 25.86. 7.76 33.62 6 F' .* MUD 415.8 1.879 . 53.252 108.92 30.42 3.38 33.80 ; -7 G-l MUD 63.2 2.714 36'. 864 73.24 . 22.23 10.32 • 32.55- • X 98.54 45.45 17.11 ' 62.56 R 26.64 22.23 3.38 32.55 / -237.28 -110.73 -:‘66.64 -177.37 UPSTREAM 8 R-l MUD 56.4 2.294 ' s 43.601 18.35 11.13 ■2.75 13.88 9 R-2 FINE SAND;‘ 21.0 1.266 79.092 283.21 17.78 10.03 •27.82 10 R-3 x MUD ,50.1 2’. 004 49.882 60.14 10.80 2.57 13.37 11 V ■ 'FINE SAND 16.9 1:203 83.115 31.28 11.55 2.89 14.44 • X 98.25 . 12.82 4.56 17.38 - R 18.35 • 10.80 2.57 13.37 • -283.21 17.78 \ 10.03 -27.32 . / 'Tr • T r r v T ' . —vT— -• ■i‘ ,\.\ \ UNIVERSITY OF IBADAN LIBRARY TABLE 51 . (c o n td .) SN Station Lithology % Wet Wt. Dry Wt. of TOE Aliphatic Aromatic THC 'Code of Sample Moisture Dry Wt. Sample (g) y z g - 1 PS g-'1 •pg g-1 y z g - 1 DOWNSTREAM • • . 12 0-1 MUD 57.3 2.339 42.783 .53.76 10.23 6.14 16.36 • 13 0-2 FINE SAND 18.7 • 1.230 81.396 ' 24.57 ‘ 22.29 9.83 32.11 14 0-3 FINE SAND 20.0 1.250 80.096 113.61 36.87 6.83 . 43.70 15 N - 18.2 , 1.222 81.941 30.51 15.99 7.20 '23.19FINE SAND 16 V • . ' FINE SAND 24.4 1.322 25.662 _118.95 58.58 12.56 71.14 17 K-2 MUD 36.5 2.139 32.056 168.46 * 26.52 * 4.68 31.20 18 T . FINE SAND . 24.3 1.321 75.730 178.27 58.70 22.80 '■ 81.50 19 . IT . FINE SAND 21.5 1.274 78.587 ' 50.90 • 28.45 5.09 33.54 20 4 -1 MUD 36.0 1.562 / .64.093 68.65 14.18 • 1. 42 15.60 2 1 ' J-2 FINE SAND 24.7 1.327 ,,75.504 37.08 18.64 3 .0 0 21'. 64 22 4-3 MUD 45.1 1.820 54.986 84.55 54.19 19.46 73.65 * X &4.48 31.33 9.00 40.33| RANGE ■ 24.57 10.23 1.42 . 15.60 UNIVERSITY OF IBADAN LIBRARY 412 • sharply in 19S5 but the differences in the m'ean values for the Jan.-Feb. 1985 samples and the June-July 19S5 samples Were not very significant-when compared to the sharp drop between.the 1984 and 1985 samples. 4.6.11 LAGOS LAGOON (JAN.-DEC,. 1985) Twenty-six points were sampled for this study and the gravimetric results for percentage inoisture, total organic extract (TOE), Aliphatic, Aromatic and Total hydrocarbon THC) are given in Table 52. The values recorded -for the • above- parameters throughout 1985 CJan.—Dec.) are 15.5-68.6$, 5.06-4373.46 (202.28), 1.25-3466.78 (1 3 7.6 7) , ( ND 8 7 . 7 3 (10.01) and- 1.25- 3554.51 T147.68) pgg 1 dry weight respectively. The highest values were recorded at Berger/ National Oil/Ijora ^LSq ), throughout the year. Green buoy # 3( I C ̂ ), mouth of Ogun • r•iver(L$l 3) , Tin- Can Island (LS 19) and Okobaba (LS 23) also recorded hydrocarbon levels indicating that they were also contaminated. UNIVERSITY OF IBADAN LIBRARY 4 1 3 TABLE 52: GRAVIMETRIC DATA OF SEDIMENT SAMPLES FROM LAGOS LAGOON (FEBRUARY-DECEMBER 1985) (DRY WEIGHT BASISl SN .Station Lithology % Wet Wt. Dry Wt. of TOECode Aliphaticof Sample Aromatic.Moisture THCDry Wt. Sample (g) pg g-1 pg g_1 ug g-1 P8 g-1 *1 LS-1 SAND 24.0 ■ 1.3150 75.6152 • 47.51 26.61 7.84 34.45 2 - LS-2 MUD 27.9 1.3865 66.0860 19.08 13.59 4.54 18.13 -3 LS-3 t ' MUD ,28.9 1.4066 ' 68.5779. . 11.61 , 4.37 ND 4.37 4 ' LS-32 . mud' 34.7 1.5312 49.9195. . 118.19 44.04 _ 20.03 64.07 5 LS-4 FINE SAND 19.2 ’ 1 1.2375 80.0396 32.48 1.25 ND 1.25 6 LS-42 • FINE SAND 21.0 ' . ‘1.2660 80.2852 13.42 • 4.98 ND 4.98 7 LS-5 MUD '56.4 ’ 2.2917 36.5639 49.23 18.20 7.73 25.93 8 LS-52 FINE SAND 21.8 1.2791 ’ 75.9876 21.52 9.21 ND 9.21 ' 9. LS-6 MUD 48.5 1.9.425 /1 45.4933 84.74 19.78 4.40 ’2*.18 10 . LS-62 MUD 58.8 .’2.4281 , 41.2294 60.64 2.43 ND 2.43 11 LS-7 MUD 54.9 2.2183 25.$431 264.48 165.78' 50.32 216.10 12 LS-72 MUD 49.3 1.9715 10.5311 140.64 89.32 18.49 107.81 13 LS-82 ' MUD 37.3 1.5958 34.1970 76.03 35.09 14.62 49.71 14 LS-92 . FINE SAND ;-21.4 1.2724 78.9539. 5.06 4.87 ND 4.87 15 ' LS-10 MUD 55.5 2.2546 35.7765 19.21 13.98 ND 13.98 16 LS-102 MUD. 56.8 2.3134 .43,7331 14.57 6.86 \ ND 6.86 17 LS-11 CLAY 25.7 1.3457 74.3087 41.77 15.39 2.70 18.09 f8 LS-112 CLAY 24,9 1.3315 77,4888 14.91 12,58 2.06 14.64 ' ) \ UNIVERSITY OF IBADAN LIBRARY 4 I 4 TABLE 52 (c o n td .) SN Station Lithology % Wet Wt Dry Wt. of TOE Aliphatic Aromatic THC . Code of Sample Moisture Dry Wt Sample (g) pg g_1 JJg g"1 y g g"1 Pg g"1 19 L3-12 . FINE SAND 21.5- 1.2732 78..3624 12.76 3.83 ND 3.83 20 LS-132 MUD 46.9 1.8837 19.0543 441.76 278.72 60.99 339.71 21 I.S-14 MUD 38.3 . 1.6209 53.9470 • 202.05 ' 12.98 3.71 16.69 22 LS-142 .FINE SAND 22.4 1.2891 77.4703 12.91 2.08 ND 2.08 23 LS-15 FINE SAND 22.6 1.2926 76.9983 58.44 5 .64 ND 5.64 . 24 LS-16 . MUD 53.3 2.1421 32.3929 60.27 34.26 ' 5.79 40.05 25 LS-17 CLAY 24.1 1.3169 75.6944 67.38 .36.61 . 33.36 39.97" 26 LS-173 'FINE SAND 19.1 1.2354 1 82.2343 60.80 6.08 3.65 /. 9.73 27 DS-175 FINE SAND •20.2 • 1.2530 82.5230 36.35 3.02 ND 3.02 28 'LS-18 FINE SAND 17.1 . 1.2063 / 83.1827 39.04 ' 30.40 4.35 • 34.75 29 LS-184 • FINE SAND 23.1 1.2996 77.6624 • 47.64 3.86 • ND 3.86 30 ‘ LS-185 MUD 29.3 1.4138 73.5842 70.38 46.21 6.79 53.00 31 LS-19 MUD 39.2 1.6459 60.3451 75.77 56.34 ‘ 1.66 58.00 32 LS-191 MUD • 68.6 3.1857 31.2446 188.83 104.616 18.07 122.68 33 LS-192 MUD 47.0 1.8885 53.0310 44.51 ' 28.48 • 5.08 33.56 34 LS-195 MUD ' 46.1 1.8556 53.9685 42.05 24.09 3.71 27.80 35 LS.-20 MUD 58.9 2.4324 34.1'364 784.28 668.39 . 26.86 695.25 36 LS-201 . MUD 37.4 1.5986 64.3146. 655.49 474.63 ''34.55 509.18 37 LS-202 MUD 44.3 1.7945 25.8833, 4373.46 3466.78 87.73 3554.51. . ». . • { , / . T \ UNIVERSITY OF IBADAN LIBRARY 4 1 5 TABLE 52 (contd.) SN Station Lithology % Wet Wt. Dry Wt. of TOE Aliphatic Aromatic THCCode of Sample Moisture Dry Wt. Sample (g) pg g-1 pg g-1 >>g g-1 P & g-1 . 38 •LS-203 CLAY 26.2 1.3544 73.8283 86.69 35.22 2.35 37.57 39 LS-205 MUD 56.3 2.2862 26.1408 604.42 429.*5,3 • 21.32 450.85 40 LS-21 MUD 42.9 1.7525 58.0720 50.78 32.72 6.89 39.61 41 LS-22 MUD 43.1 1.3319 71.5276 68.65 25.98 2.35 28.33 42 LS-222 COARSE SAND 15.5 1.1838 * 80.5031' 47.20 ' 22.42 1.06 23.48 43 LS-225 FINE SAND 20.0 1.2467 85.8841 79.18 3.49 1.16 4.65 44 LS-23 * • MUD 65.7 2.9151 33.7594 188.86 129.62 ' .18.95 148.57 45 LS-232 MUD • • 65.8 2.9205 ‘ ’ 20.3078 364.39 258.20 23.85 282.05 • 46 LS-234 MUD 40.6 1.2823 60.3686 351.23 ' 207.09 15.30 222.39 47 LS-24 CLAY 20.8 ' 1.2619 78.6274 ‘ 232.75 169.25 12.75 182.00 48 LS-242 CLAY 23.8 1.3116 . 75.9546 ‘ 23.70 2.63 1.32 3.95 49 ' LS-245 CLAY 24.3 1.3205 ' 76.4522 98.10 67-. 00 9.42 76.42 50 LS-25 MUD 38.6 1.5284 46.6775 52-. 14 39.56 4.28 43.84 51 LS-252 FINE SAND’ 22.2 1.2852 78.8033 8,88 5.09 ND 5.09 52 LS-26 \ MUD ‘ 38.0 1.6124 59.7530 55.23 8.37 ND 8.37 53 LS-262 MUD • 65.7 2.9196 9.4351 107.49 . 84.79 10.60 95.39 t UNIVERSITY OF IBADAN LIBRARY 416 UNIVERSITY OF IBADAN LIBRARY 417 4.7 GAS CHROMATOGRAPHIC DATA the hydrocarbon the sediment of CT - O 014) is show:rn in Fig. 35, together with baseline. n-1Allkkaa'ne ranging from -to C-^j Pristane, phyt annee,, and a large amount of unresolved complex mixture (UCM) are found in the chromatogram. The UCM constituted the major portion of the hydrocarbons. The Gas Chromatographic analysis served to identify and quantify the petroleum hydrocarbon compounds present in the samples. The relative con­ centrations of individual compounds identified the composition of oil present, and the absolute concen­ tration served as a measure of the amount of oil present. The concentrations of certain compounds, e.g. phytane, pristane etc. were also used to calculate indicator ratios that reveal the type of hydrocarbons qrfesent i.e., biogenic or petroleum, and .the weatherin age of the petroleum. The gas chromatographic concentration of the resolved alkanes, the unresolved complex mixture (UCM) UNIVERSITY OF IBADAN LIBRARY 418 hydrocarbons, total aliphatic, total aromatic and the total hydrocarbons for all the sediment samples analyzed in '19S4 and 1985 are reported in Tables 53 to 6S, under the different river systems. 4.7.i LAGOS AND LEKKI LAGOONS • The results of the 1984 samples are shown in Table 53. The concentrations of'resolved alkanes, UCM, total aliphatic, total aromatic and total hydro­ carbons for the sediment samples ranged from a non- detectable level (85) (ND) to 10. 8 4 p g g (845) with an average of 1.88pgg_1, ND - S0.23pgg_1 with an average of 25. Olpgg ■ , ND to 91.07pgg ̂ with an average of 26.85 jagg ^ , ND to 7.16 with an average of 3.48pgg ̂ and from ND to 95.54 with an average of 30.33pgg- ̂ respectively. The carbon range found-in the samples was C,g - The highest concentration of total hydrocarbon was found in sample from Lever Brothers’ discharge j>oint (845) - 95.54pgg as earlier indicated by the gravimetric results. The sediment sample from Iwopin did not show any detectable level. UNIVERSITY OF IBADAN LIBRARY <119 TABLE 53 THE HYDROCARBON ■CONTENT IN SEDIMENT. AROUND LAGOS AND NIGER DELTA ' AREA OF NIGERIA IN PPM ON DRY WEIGHT BASIS (BY GC) SN Station Carbon Aliphatic Aromatic TotalCode Range Resolved UCM Total Total Only HydrocarbonAliphatic 1. LAGOS--LEKKI LAGOON 1 086 C19"C32 0.35 10.22 ' 10.57 2.90 13.47 2. ' 087 C20~C33 .0.22 9.19 9.41 1.12 ,10.53 '3, 845 . ' C16_C33 ' • | *10.84 80.23 1 . 91.07 . 4.47 95.54 4, ' . ’ 847 C19_C26 0.67 37.-65 . 38.32 7.16 45.48 * 5 851' C20-C32 ' ' 0.70 19.34 ' . 20.04 3.14 • ' ' 23.18’ 6 856 •ND . • ND ND ' ND ND 7 857 C19“C30 • . 0.39. ' /l8.15 18.54 5.55 24.09 X 1.88 . 25.Oi 26.85 3.43 30.33 SD ±1.55 ±11.46/ .±13.01 ±1.02 ±13.65 ' . R. ND-10.84 • ND-80.23 ND-91.07 ND—7.17 ND-95.54 . 2. BENIN , 8 057 C16_C31 1.79 ND 1.79 1.21 3.00 9 3.34 CI6"C32 1.11 3.21 4.32 l . V 5.89 1° • 311. C16-C32 » 0.16 1.33 1.99 0.68 2.67 11 347 C16_C31 0.06 1.08 1.14 • ' 0.91 2.05 12 • 835 C18-C26 0.04 ' ND 0.04‘ ND 0.04 13 837 C18-G32 0.99 3.01. 4.00 2.26 6.26 I I UNIVERSITY OF IBADAN LIBRARY 4 20 TABLE 53. (contd.) SN- Station Carbon Aliphatic Aromatic Total Code Range Resolved • OCM Total •Total Only Hydrocarbon ’Aliphatic 14 83*8 C. _-C 0.28 7.32, 7.51 1.63 . 9.14 15 19 32 * 0-1 c 19_ -c28 0.08 * ND . 0.08 0.02 ' 0..10 1.6 0-2 C19-C29 .4.32 • 36.90 41.22 1.63 42.85• X 0.98 5.92 . 6.90" • i.io 8.00 SD ±0.48 •. ±4.10 ±14.58 , ±0.25 ±4.76 * . R ; . ' 0.04-4.32 - ND-35.90 0.04-41.22 • ND-2.26 • 0*. 04-42.85 1'• 3. ESCRAVOS 1 17 054 1.06 57.39 58.45 5.68 64.13 18' 055 C16"C32 • 1.76 . • ND 1.76 0.54 2.30 19 360 ci6-c j a .. 1.20 2.46 3.66 - 0.604 4.26c , - c 20 362 16 33 0.56- -• 8.16 . 8.72 1.76 10.48 21 831 \ C16-C31 • ' 0.87 NND 0.87 0.04 0.91 22 839 C18"C32 . 1.06 1 ND .1.06 0.43 1.49 C19_C31 1.09 11.34 12.42 • 1.51 13.93 X • SJ> +0.20 ±9.57 ±9.50 ‘ ±0.94 ±10.54 R 0.56-1.76 ND-57.39 0.87-58.45 0.04-.-5.68 0.91-64.13 I UNIVERSITY OF IBADAN LIBRARY 421 TAB1.E 53 '(contd.) SN Station Carbon Aliphatic Aromatic Total Code Range Resolved UCM Total Total Only Hydrocarbon . \ Aliphatic 4. F0RCAD0S 23 040 C16~C31 0.08 0.20 0.28. 0.03 0.3124 049 C24"C27 0.14 0.97 1.11 0.23 ' 1.3425 050 C1Q-C?7 ■ ’ 15.84 ND 15.84 3.68 19.52 26 ' . 052 C17-C31 0.18 .0.45 0.63 0.21 / 0.8427 053 28 351 . C19'C32 1.04 '26.64 . 27.68 * 2.54. 30.22 C19-C31 0.13 '/ 1.50' 1.63 ' 0.25 1.88 29 • 352 C16-C30 . • 6.65 ND ‘ 6.65 0.52 ’ 7.1730" ■353 c?n~C3i 0.15 2.30 2.45 0.15 2.60 31 372 1.22 • 2.95 4.17 0.24 4.41 32 858 C16~C32C1.6"C28 16.19 53.33 69.52 4.53 74.05 ■ 33 860. 34 862 _ C20~C31. 0.26 4.64 4.90 1.77 6.67 C-16"C29 0.56 3.76 * 4.32 0.56 4.88 35 863 C16‘C30 5.52 ND 5.52 ,0,42 5,9436 864 c.i 0,31 3.75 4.06 0.35 4.41 37 865 .C1 6 “0 32- 3.68. 28.76 32.44 1 1.30 33.7438 866 C zO -•f ' *30 0.06 2/00 2.06 0,46 2.52 . I UNIVERSITY OF IBADAN LIBRARY 1 Vii . ' i i| .r', •, _ * - . • • _■422 . # ./ ' f. *; •T. •, 1 •TABLE 53 (contd.) • ' ' •■ K !' ' t1. , » ii SN Station Carbon . Aliphatic . Aromatic Total SN . Code Range ■ !Resolved ' UCM . Total Total Only Hydrocarbon , ; f • • Aliphatic • l • ’ |, X '3.25 8.20 11.45 . 1.08 12.53 SD ±1.01 l * ±3.33 ±4.33 ±0.. 23 • ±4.61 1I R , Q.06-16.19 ND-53.3i .• 0.28±69:52 0.03-3.68 0.31-74.05 1* * 5. RAMOS * • • / • 39 038 . C16"C27 . • • 8.06- 27.04 35.10 2.22 37.32 40 382 C16_C32 • • 5.81 ' ' j ND ' 5.31 0.83 6.64 • 41 869 . C18"C33 0.19 • v 6.80 6.99 0.63 7.62 42 870 C16-C28 5.98 60.93 • 66.91 4.73 71.64 • 43 871 C23-C28 0.07 ' • ND . 0.07 . 0.05 . 0.12’ 1 X 4.02 18.95 22.98 . 1.69 24.67 SD ±1.60 ±12.19 ±13.34 1 • ±0.94 ±14.30R 0.07-8.06 ND-60.93 0.07-66.91 0.05-4.73 0.12-71.64 . 1 . 6. SON - EKOLE - BRASS \\ ' 1 ■ - 4 4• 036 C19-C311' ND ND ND ND ND 45 043 jC16“C31 • 0.21. 13.61 13.82 1.74. ' 15.56 46 281 C20-C31 0.26 ND 0.26 0.06 0.. 32 | 47 871 C20_C31 0.12 3.79 3.91 0.63 4.54 •48 873 C22-C32 0.16 3.24 3.40 0.31 . / 3-71 ! ! . ? • . j • i UNIVERSITY OF IBADAN LIBRARY \ 423 TABLE .53 (contd.) SN Station Carbon , Aliphatic , Aromatic Total Code Range Resolved ycM Total Total Only HydrocarbonAliphatic • X 0.■15 4.13 4.28 0.55 4.83Si e ±0.05 • ±2.72 ±2.76 . ±0.35 ±3.11 ND-0.26 ND-13.61 ND-13.82 ND-1.74 ND*-15.56 . 7. ■ ORASHf e • i 1 • * ’ • 49 012- C16-C31 ' • ■. 0.L7 ND ' 0.17 ' ND _ . / 0.17. 50 0.3 .C167C31 0.20 _ . 1.05 1.25 / 0.62 1.87 51 014 C16-C31 • . 1.23 ’ ■ // 2.85 - . 4.08 2.10 6.1852! 016 C16“C32 0.47 3.41 * 3.88 1.21 5.09 53 021 C19_G32 0.20 4.83; 5.03 1.15 6.18 54, 035 C16-C31 0.58 • . KD 0.58 0.05 0.63' * 55- 250 C16-C30 0.13' ND ' 0.14 ND ' 0.13 56 251 C16“C3.1 0.08 1.56 1.64 ' 0.03 1.67 57 252 C.1_7 -C„3„2 1.95 ND 1.95 ND 1.95 58 262 C16_C32 0.32 0.63 0.95 0,\31. 1.2660 802 C ,-C ' 0.25 ' 1.90 2-. 15 0.63 2.78 61 • 82 i 16 32 ;• ' 0.16 ND 0.02 C18-C31 . 1 ND 0.23 62 824 0.02 . ND ND .0.02C18~C31 0.02 UNIVERSITY OF IBADAN LIBRARY 424 TABLE 53 (contd.) SN Station Carbon Aliphatic Aromatic Total Code Range Resolved UCM Total Total Only HydrocarbonAliphatic • X 0.50 1.16 1.66 0.48 2.14 SD ±0.13 ±0.35 ±0.36 ±0.44 •±0.44 • R • 0.02-1.95 ND-4.83 .-0.02-5.03' ND-2.10 0.02-6.18 i 8. BONNY - NEW CALABAR- *j * ' . / « 63 020' r. 16 -cL.32 0-. 87 • ' /0.34 1.21 . 0.04 1.2564 121 r. -r •0.24- . ND 0.24 0.02 0.26 65 233 r. 17 -r.32 0.55 • 6.76 7.31 1.20 8.51 66 807 °16 l32 3.69 C16-C31 13.55 1 • 17.24- 4.20 21.44 . •67 . 808 68 810 ' C16"C3r 0.59 1.41 .2.00 0.15 2.91 ' C18-C32 0,88 ND 0.88 0.03' 0.91X 1.14 : 3.68 4.81 * 0.94 5.75 S - SD ±0.58 ±2.26 ±2.83 ±0.70 ±3.53 R ' 0.24-3.69 ND7I3.5 5 0.24-17.24 0,02^4,20 0.26-21,44 ■ 9’ IMO ' if • 1 69 128 0.20 8.55 8.75 . 1.41 . 10.16 70 813 C16_C33 C18"C3i 0.29 1,06 1.35 0.43 1.7,871 817 C16'C31 0.25 ND 0.25 0.05 0.30 UNIVERSITY OF IBADAN LIBRARY 4 2 5 TABLE 53 (c o n td .) SN Station Carbon Aliphatic Aromatic Total Code Range Resolved UCM Total Total Only HydrocarbonAliphatic X 0.25 3.20 3.45 0.63 4.06 4*> ±1.03 + 2.85 +2.83 +0.45 +3.29 e. 0.20-0.29 ND-8.55 0.25-8.75 0.05-1.41 0.30-10.16 10. CROSS RIVER - CALABAR 72 071 C16~C29 0.57 2.10 2.67 0.03 2.7073 811 74 812 C16"C31 0.22 ND 0.22 0.04 0.26 0.46 ND 0.46 0.06 4.41 75 827 C16-C31 C16-C33 0.44 3.35 3.79 0.62 4.417 0.42 1.36 1.79 . 0.19 . 1.97 it> ±0.09 ±0.84 ±0.89 ±0.15 ±1.04 a 0.22-0.57 ND-3.35 0.22-3.79 0.03-0.62 0.26-4.41 11. KADUNA 76 141 A C,1 6 -C32 0.25 20.25 20.50 1.02 21.5277 141 B 78 843 C16"C32 0.84 16.26 17.10 0.92 18.02 C,1 ,6--C32 0.15 0.43 0.58 0.04 0.6279 844 _ C 16, -C32 0.64 8.56 9.20 0.07 9.27X 0.47 11.38 11.78 0.51 12.36 ±0.17 ±4.96 ±4.92 ±0.25 ±5.23 0.15-0.84 0.43-20.25 0.58-20.50 0.04-1.02 0.62-21.52 UNIVERSITY OF IBADAN LIBRARY i 426 4.7.2 NIGER' DELTA . • •= * • . • In the delta area the results showed wide varia­ tion in between samples from the same river system and also from one river system to the other. The highest concentration of total hydrocarbons were found in the following river systems: Forcardos - Warri 0.51-74.05 (12.53), Escravos -0.91-64.15 (13.93) and Ramos - 0.12-71.64 (24.67) pgg ^. The other river systems have mean values of .total hydrocarbon below 1° pgg ̂• Benin — CL. 4-42.85 (8'. 00), Nun *- -Ekole- Brass: NE) - 15. 56 (4.83), Orashi: 0.02-6.1'8 (2.14), Bonny - New Calabar:' 0.26-21.44 (.5.75),, .Imo: 0.50- 10.16 (4.08) and Cross River - Calabar: 0.26-4.41 (1.97) pgg,1. . The carbon range for the river systems are mainly C32 and Cig - C32. Only few points were selected for sampling in 1985' (dry.season - Jan.-Feb.). The results of the total fiydrocarbons reported for the 1985 samples, in respect of the Lagos and Lekki Lagoons and the Niger Delta river systems are shown in Table 54. UNIVERSITY OF IBADAN LIBRARY 427 TABLE 54 THE HYDROCARBON CONTENT IN SEDIMENT AROUND • LAGOS AND NIGER DELTA AREAS 07 NIGERIA IN PPM OX DRY WEIGHT BASIS (FEBRUARY 1985) (BY GC) ■ SN StationCode Aliphatic Aromatic Total Hydrocarbons 1 LAGOS - LEKKI LAGOONS 1 • 845 1.50 0.61 2.11 • 2 851 0.20 ND 0.20 3 857 9.00 1.30 10.30 X 3.57 0.64 . 4.20 * * SD ±2.93 ±0.43 - ’ ±3.37 RANGE 0.20-9.00 ND-1.30 - 0.20-10.30 2 • BENIN . .4 311 1.00 0.02 • "1.02 3 ESCRAVOS • v 5 054 41.00 3.06 • 44.06 6 055 6.70 1.10 7.80 7 830’ 1.40 0.08 1.48 8 833 1.40 0.05' 1.45 ' •9 834 0.20 ND 0.20 X 10.14 0.86 ’ 11.00 SD ±8.16 ' ±0.61 ±8.77 R 0.20-41.00 0.05-3.06 0.20-44.06. 4 FORCADOS • • 10 040 0.50 0,02 0.52 11 049 12.00 2.46 14.46 12 050 13.00 3.48 16.48 13 052 30.00 2 , 9 7 32.97 UNIVERSITY OF IBADAN LIBRARY 4 28 > . * TABLE 54 (contd.) •SN Station Code . Aliphatic Aromatic. Total Hydrocarbons 14 • 053 . 0.30 0.06 0.36 15 351 0.10 ND 0.10 16 353 1.30 0.09 ' 1.39 17 860 5.80 - 1.05 6.85 * •18 •862. 1.80 0.14 ‘ 1.94 19 866 0 .'20 . 0.16 ■0.36 X 6.50 1.04 • 7.54 \ SD ±2.99 • ±0.35 ±3.29 R 0.10-30.00 N15-3-.48 . 0.10-32.97 % 5 ORASHI • • 20 021 1.50 0.08 • 1.58 21 250 • 0.10 0.02 0.12 22 252 23.00 ' 2.10 ■ 25.10 23 801 . 0.60 0.43 1.03 24 . .819 1.30 0.32 1.62 ' 25 820 0.30 0.06 ‘ 0.36 26 821 0.60 0.17 0.77 • X 3.91 - 0.45 4.37 sp ±3.81 ±0.35 ±4.16 R 0.10-23.00 0.02-2.10 . 0.12-25.10 6 BONNY - NEW CALABAR' N. . 27 018 7.40 1.02 8;42 28 020 10.00 2.52 12.52 UNIVERSITY OF IBADAN LIBRARY 429 TABLE 54 (contd.) ss StationCode Aliphatic Aromatic * Total Hydrocarbons ' _ ; if 121 2.00 0.81 2.81 30 807 1.60 0.17 ;i.77 31 808 0.20 0.04 0.24 • • X 4.24 0.91 . * 5.15- — -3 SD ±1.96 ±0.50 ±2.46 - R 0.20-10.00 0.04-2.52 0.24-12.52 ' 7 CROSS RIVER - CALABAR * . • 32 079 ' 9.20 2.14 * ' 11.34 33 210 0.05 ■ ND 0.05 ’ — . X 4.63 1.07 5.70 - . SD ±4.58 ±1.07. ±5.65 R 0.05-9.20 ND-2.14 0.05-11.34 8 KADUNA • • 34 141A 2.30 0.61 2.91 35 141B 4.00 1.00 • 5.00 X 3.15 0.81 3.96 SD ±0.85 ±0.20 ±1.05 R 2.30-4.00 0.61-1.00 2.91-5.00 / ' IBADAN' * Ag-1 27.794 ND 27.794 C15_C33 - As-2 6.849 1.241 8.090 C16'C35 X 17.32 ■ G.-62 17.94 SD ±14.81 ±0.88 ±13.93 L R 6.85-27.79 ND-±.241 8.09-27.79 * i UNIVERSITY OF IBADAN LIBRARY / 430 According to the results, Lagos and Lekki Lagoons recorded between 0.20 and 10.30 pgg ̂ dry weight for total hydrocarbons. All the other river systems in the Niger Delta area recorded between 0.05 and 44.06 pi gg ̂ total hydrocarbons. The highest- was recorded at Escravos Terminal (054) - 44.06 pgg ^, and the lowest concentration of total hydrocarbons was recorded at a point on Forc.ados river below the mou-th of Oyeye creek (351) - 0.10 pgg 1. For comparison, Kaduna samples gave 0.62-24.52 (12.36) ugg ̂ total hydrocarbon Agodi and Asejire recorded 27.79 and 8.84pgg THC respectively. ' • 4.7.3 UTOROGU lSh'AMP AND OKPARI RIVER The results of the 1984 samples for the hydro­ carbons during the rainy season (Oct.-Nov. 1984) are shown in Table 55. The resolved alkanes - 0.74-46,. 26 (11.02) pgg'1, UCM‘: 7.38-222.90 (79.30) pgg_1, total jiliphatic: 10.42-241.28 (91.76) jigg total aromatic: . ND - 40.01 (9.90) jagg " and total hydrocarbons: 14.04- 267,48 (101.66) pgg ̂ dry.weight of sediment. UNIVERSITY OF IBADAN LIBRARY 4 31 TABLE 55; THE HYDROCARBON CONTENT IN SEDIMENT AT UTCROGU SWAMP AND OKPARI RIVER IN SENDEE STATE OF . NIGERIA (I'i’M DRY WEIGHT 11ASIS) (BY CC) (OCTOBER - NOVEMBER 1984) SN Station Carbon Aliphatic Aromatic Total Code Range Resolved . UCM Total Total Only Hydrocarbon Aliphatic IMPACTED SWAMP • 1 B ^22~C28 28.78 85.27 114.05 • 40.01 154.06 2 D ' C20-C29 2.27 ' • 103.63 105.90 20.90 126.80 3 •. • E . C ,"C32 3.18 23.19 26,37 5.50 . 31.97 ' •. 4 G-l C20_C31 4.81 _ 37.38 , 42.62 3.55 46.17 5 ‘ G-2 X 18"C32 4.81 . 35.53 40.4 / 2.37. 42.71 6 G-3 . C20“C28 12.55 ./ 39.32- 51.87 * 3.72 _ 55.59 7 ; , G-4 C20_C28 ’ 21.53 102.56 124.09 9.96- 134.05 X 11.19 ' 60,98 • 72.18 12.30 84.48 , R ’ 2.27-28.78 23:.-19-103.63 .26.37-124.09 2.37-40.01 31 .97-154.06 Ul’STEAM / . R-l . C18_C32 • 3.27 86..42 . 94.73 ' 3.11' 97.84 9 R-2 C19~C32 . 3.27 148.46 “'151.73 ND 151.73 10 R-3 C20-C30 2.U 91.01' 93.12 \. 17. 97.29 X 4; 56 108.63 113.19 2.43 115.62 R DOWNSTREAM 2 ..11-8.31- 86.42-148.46. 93.12-151.73 ND-4.17 97.29-151.73 11 0-1 ■ C17"C31 18.38 222.90 241.28 26.20 267.48 • ‘ . / ' " ' rTrrrrrn-̂r UNIVERSITY OF IBADAN LIBRARY M ■ ’ i! ' ‘ . V;". . ■ ' :• •'J; 432 *> { 1 • TABLE. 55 (contd.j' .. [• j . SN Station Carbon Aliphatic Aromatic Total I' • Code Range iesolved UCM Total Total Only HydrocarbonAliphatic J ; J 12 0-2 917*”C32 26.14 _ 150.66 ’ 202.93 13.90 216.83 l 13 • N ; C20~C23 0.74 - 44". 00 44.74 7.50 52.24 i • 14 • . V e2|,“C32 ‘ • . 3:89 11.06' . _. 14.95 . 4.60 19.55 15 •« ' K-3 C20_C33 3:04 7.38 . . 10.42 3.62 14.04 . *16 • K-3 ' i C20-C38 46.26 99.76 146.02 25.70 • ' 171.72 17 X ' 6.54 • ' 83.38 89.92 2.10 92.02 • 18 , U C20-C32 • 1.23- • ,/55.45 56.68 1.15 57.83 C18-C32 (| X 13.28 • 84.32 100.87 10.60 111.46 R 0.74t46.26 7.38-222.90 10.42-241.28 1.15-26.20 14.04-267.48 J l • 1| ' * • \;«■ \\ . . •' I / • s j • 1\ . 1j •/ • i . • • * \ V — .1 V/ ■ r : \ r UNIVERSITY OF IBADAN LIBRARY r 453 These levels came down drastically during the January^February period (dry season) in. 1985 as the results-in Table 56. revealed, resol ved ' alkanes :. ND - 1,014 CO.17) pgg-1, UCM: ND - 7.336 (1.94) pgg-1 , total al iphat ic:' ND - 7,961 (2.106)- pgg ̂, total' aromatic: ND 2'.01 (0.387) pgg ̂ and. total hydro­ carbons; N'D - 9.414 (2.49) pgg . The levels of- hydrocarbons recorded during the 1985 (wet season), for the Utorogu swamp and Okpari are reported in Table 57. The values were higher than those reported for- the early (dry season) "1985 samples. The resolved alkanes' range-from 0-.02 to 15.07 pgg 1 with an average* of 2.76pgg_1, other levels* are UCM: ND - 62.77 (17.05) pgg ^ , aromatic: *ND - 4.11 (0.814) pgg ̂ and total hydrocarbons:- 0.05-68.06 C20.62) pgg 1 . For comparison, the Lagos Lagoon samples collected between January and December 1985 gave the. results' "reported in Table 58. Resolved alkanes: .ND - 179.23 (10.67), UCM: ND - 2524.15 (95.40), total aliphatic: XD -' 2703.38 (104.11), total aromat.ic: ND - 62.89 UNIVERSITY OF IBADAN LIBRARY " • TABLE 56: THE HYDROCARBON CONTENT IN SEDIMENT AT M ’OKOCU SWAMP AN'D OKI’ARI RIVER IN DENDKL STATE OF NIGERIA (PPM DRY WEIGHT BASIS) (BY GC) “ (JANUARY - FEBRUARY 1985) --- -- -- - - -- Station . Carbon Aliphatic ■ ■Aromatic Total SN ■ • Code Range Resolved UCM Total Total Only Hydrocarbon * Aliphatic IMPACTED SWAMP T------ M C20-C26 0.07 * 7.34 . 7.40 2.01 9.412 B2 f . ' C2rC33 Q.08 . 2.14 2.22 1.62 3.84•3. • + C C -C 0.04 1.17 . 1.21" ' ND 1.214 D • C20-C32 0.05 0.47 0.32 0.29 0.81 -5 El C20“C33 0.33 2.37 2.70 0.40 • '3.10 6 El ' ’ C19-C33 0.27 / 5.74 ' 6.01 0.36 6.37 7 ■ F ND ND ND ND ND i 1 I i! ' X - 0.12 2.75 2.87 .• 0.67 3.58| UPSTREAM R ' ■ ND—0.33 ■ND-7.34 . NIJ-7.40 ND-2.01 ND-9,41."8----- R-l ND ND ND .ND ND' 9 R-2 C22~C28 0.26 - 0.56 •0.83 0.11 0.94 * . X \ \ 0.13 0.28 - 0:42 0̂ \06 0.47 DOWNSTREAM-R ND-0.26 ND-0.56 ND-0.83 ND-0.11 ND-0.94 • 10 0-1 C20"C32- 0.81 0.24 0.26 . ‘ , 0.17 0.43 . 11 0-2 C20_Ci33 0.30 0.70 1-.01 051 1.5212 0-3 ’ S?3 -C32 - 0.30 0.70 1.01 0.51 1.52 1 N C22-C33 0.03 0.69 • 0.73 0.27 1.00 • . 14 K-2 C19“C32 0.03 0.58 0.61 ‘ 0.06 • . y°-6715 T X • C20~C27 1.01 •6.95 7.96 ND 7.96 0.23 1.55 1.79 0.20 1.95 . T ‘ f t. / • • ’ ' ’ r •-• vi s UNIVERSITY OF IBADAN LIBRARY TAHI.E ">7 ! Till1: IlYliKOBCEANHHON CONT 435 DEL STATE KNOTF NI NIG_ES1R11I)A I Ml(iPNPTM A DTR»YU TOWKEUIGCUH T SWBAAMS!I' S)A ND( jjOy igC-ACU) I RIVER JN ( JUNE - JULY 1985) Station Carbon Aliphatic Aromatic Total Code Range Resolved UCM Total . Total Only HydrocarbonAliphatic IMPACTED SWAMP * * !•{ 1 A-1 . C19_C32 0.13 2.09 2.22 ND 2.22.' 2 B • * C19-C32 - 1.19 62.77 ' 63.95 ' 4.11 / 68.06 * 3 ' C-2 • C24-C29 0.12 2 .83 . 2.95 0.58 3.53 4 C-3 G22-C30 0.28 • 2.88 • 3.15 ' 0.54 3.69 5 ! D C20"C29 • 4.07 15.02 19.08 4.63 23.76 6 ’ F ‘ iC20-C27 • 3.88 14.4J - 18.35 1.91 20.26 7 1 G-l C20“C33 1.18 14.17 15.35 0.13 15.48 X R • 1.55 16.32 17.86 1.11 ’ 19.57 • UPSTREAM . 0.12-4.07 ' 2.09-62.77- 2.22-63.95 ND-4.68 2.22-68.06 ' ' \ 8 R-l C17-C29- 0.02 : ND 0.02 0.01 0.03 9 R-2 C19~C31 ■- 3.36 . 21.38 24.74 • 1 2.02 26.76 10 • R-3 \ C19-C27 0.56 3.12 - 3.67 0.20 3.87 . 1 1 P C19_C28 0.06 1.93 1.99 0.42 2.41 * X R . 1.00 6.61 7.61 0.66} . 8.270.02-3.36 ND-21.38 0.02-24.74 0.01-2.02 0.03-26.76 . . 1 ■ : \ ■ • y >/ 'v- ■; \ UNIVERSITY OF IBADAN LIBRARY 436 TAIU.I'1, 57 (coni ri ■) Station Carbon A1iphaticSN A.roraatic TotalCode Range Resolved \ l!CM Total Total Only HydrocarbonAliphatic DOWNSTREAM 12. 0-1 e22-C32 0.96 13.49 14.45 0.57 15.02 13 0-2 C19-C28 5.H 11.00 22.11 0.67 •22.78, 14 ■ •°-3 . C19-C33 1.84 20.58 22‘.42 ND , 22.42 15 N C19~C32 C.84 21.80 22.64 ND 22.64 16 • V . C19_C29 8.86 * ND 45.90• / 37.04 ‘ 45.90 17 M C19-C33. 3.48 ' 11.21 • 14.68 ND ' 14.68 . is/ K-2 C20"C32 1.17 7.76 8.93 ND 8.93 19 . J . C19"C31 4.82 . ’47.75 * 52.58 0.39 52.96 • 20 U C19~C32 3.36 23.33 26.69 ND 26.69 21 .. j-i Q19-C32 o.45 5.99 ^6,44 1.78 8.22 22 J-2 C19-C32 2.63 ,12.57 15.19 0\07, 15.26 23 J-3 C19~C32 15.07 33.01 48.03 0.66 48.74 X 4.05 20.96 25.01 0.35 25.35 RANGE 0.45-15.07 5.99-47.75- 6.44-52.58 ND-1.78 8.22-52.96 . I -rv-r-r- UNIVERSITY OF IBADAN LIBRARY 437 TABLE 58; THE HYDROCARBON CONTENT IN SEDIMENTS AROUND I.ACOS T.ACOON (PPM DRY WEIGHT BASIS) . ........ ̂J a n u a r y " "De c e m b e r " jV k s ) ... (b y g c ) SN Station Carbon Aliphatic Aromatic Total Code Range Resolved UCM Total Total Only HydrocarbonAliphatic 1 LS-1 C17_C27 1.93 21.88 23.81 4.34 28.15 2 LS-2 . - C20"C30 0.57 11.21 11.79 1.67 13.46 . 3 LS-3 * C22-C27 0.31 ND 0.31 ND . 0.31 4 LS-32 C18_C34 4.67 33.58 38.25 5.62 / 43.87 5 LS-4 C16-C29 1.15 .ND 1.15 . ' ND , 1.15 6 LS-42 C20~C30 2.22 • / ND 2.22 ND 2.22 7 : LS-5 C17-C30 • 1.32 15.83 • 17.16 3.11 ' 20.271 . 8 LS-52 C18~C31 0.17' ND j 0.17 . ND 0.17 9 LS-6 C19-C29 1.54 15.07 16.61 2.04 18.65 10 LS-62 - ND ND ND ND ND. 11 LS-7 C16~C25 7.30 124.60 131.90 33.50 165.40 12 _ LS-72 C20rC24 25.12 ND 25_.12 15.70 40.82 13 . LS-82 ‘ r i8 w2.9 1.63 ND 1.63 N\D 1.63 14 LS-92 • C21-C30 . 4.66 ; ND 4.66 ' Nil ' 4.66 15 LS-10 C20-C25 5.19 ND 5.19 ■ ND 5.19 16 LS-102 C20~C29 ' 0.41 ND • 0.41 ND . 0.41 17 ' LS-11 ■C17_C32 1.20 11.30 12.50 2.40 14.90 •13 LS-112 C19_C32 1.26 7.15 8.41 0.52 8.93 19 LS-12 C20-C30 0.48 ND 0.48 ND ' y.48 ' i 1 _' _ _ y UNIVERSITY OF IBADAN LIBRARY \ 4 38 TABI.E 58 (cont d.) SN Station Carbon Aliphatic Aromatic Total Code Range Resolved • UCM Total ’Total Only Hydrocarbon’Aliphatic 20 LS--132 C18~C29 43.60 163.96 ‘ 207.56 .31.25 238.81 21 LS-14 C25CC32 1.48 ND 1.48 ND . 1.48 22 LS-142 , ' C25~C29 0.19 , ND * 0.19 . ' .ND 0.19 23 • LS-15 C18~C31 •3.88 ND 3.88 ND 3.88 24 LS-16 C20"C29 ' 7:60 20.50 28.10 3.42 ' 28.10 25 LS-17 •C18"C25 ■ 0.79’ 28.42 29.22 1.05 30.26 26 LS-173 C20~C32 • 0.62' / nd 0.62 ND 0.62 27' ' LS-175 ■ C20_C31 0.25 ND ND 00.25 28 LS-18 C20-C31 2.05 22.79 • 24.83 2.62 27.46 . 29 LS-184 c -c ND ND ND ND ND 30 LS-185 C19-C26 8.30 ND 3.30 0.84 9.14 31 LS-191 C23_C29 •18.56 ND 18.56 : nd 18.56 32 " LS-192 C16-C25 5.83 89.40 95.23 14.10 109.33 33 LS-192 C18'C26 0.72 ,22.73 23.45 '3.91 27.36 34 LS-195 C19_C29 , 4.12 ND 4.12 ND 4.12 35 ' LS-20 C16"C27 ■ 29.87 488.72 518.59 ■ 20.70 539.29 36 LS-201 9.34- 387.>36 396.70 31.18- 427.88 37 LS-202 14 -25 179.23 2324.15 2703.88 62.89 2766j27 . / UNIVERSITY OF IBADAN LIBRARY 4 39 TAlU.l'i 38 (coin'll.,) SN Station Carbon Aliphatic Aromatic ■ Total Code Range • Resolved' UCM Total Total Only HydrocarbonAliphatic 3838 •• "LS-203 C14_C24 179.23 11.97 12.77 1.87 14.64 39' LS-205 C14~C34 11.88 381.53 393.40 ■ • 16.42' • 409.82 40 LS-21 ' 'C17~C25 4.34 23.92 28.26 2.35 30.61 _ • 41 LS-22 ' "cr7 -c3i , 1.57 20.76 •22.34 . 1.79 . 24.13 42 ■LS-222 • C,„-C„4 1.91 17,30 .19.22 0.80 / 20.02 43 LS-225 17 27 C00-C„, 0.47 ND 0.47 / * ND . 0.47 44 LS-33 lr 21S7 r 3 i 10.56 '101.74 - 112.31 14.02 126.322 6 45 ! LS-232 C17~C34 .41.11 174.01 ' 215.12 18.67 ' 233.79 46 . LS-234 C22-C29 6.85 152.45/ 159.30 12.75 172.05 47 , . LS_24 . C17_C32 17.49 120.‘39 137.88 10.20 148.09 48 . LS-242 C19-C24 0.71 ND 0.71 ND 0.71 49 LS-245 C17_C32 -.5.52 44.47 49.99 5.42 _ 55.41 ■50 -iS-251 C18-C32 20.17 19.00 39 a 7 3.61 42.78 51 LS-252 C22_C28 1.34 ND 1.34 l̂ D 134 52 LS-26 C22-C31 ' 3.51 : ND 3.51 ND ’ 3.51 53 LS-262. r' 20 _r 29* 59.75 ND 59.75 ND 59.75 X '10.67 95.40' 104.107 6.088 * 110.131' SD • ±3.38 ±47.63 ±51.01 ±1.19 ±51.19- R • ND-179.226 ND-2524.15 « ND-2703.380 ND-62.885 ND-2766.265 UNIVERSITY OF IBADAN LIBRARY 440 (6.09) and total hydrocarbons: ND - 2760.27 (110.13) pgg ̂ dry weight of sediment. 4.8 DISCUSSION Aquatic sediments are regarded as the main final accummulation site of water-borne constituents derived from natural and artificial sources. They are also possible sources of chemical constituents in waters. Several authors have demonstrated that in an aquatic system the underlying sediments can act as an indicator of processes in the wateT ColUtnn^^ ’ ̂ ^ . Conover^^^ has also concluded / , - -' ■ - that zooplankton were responsible for the removal of oil droplets from the water column by ingestion and subsequent sedimentation in association with faecal material. The concentration of particulate organic matter has also been implicated as a vehicle for the transport of hydrocarbons from the water column to the sed,i. ment (256,257) • . : UNIVERSITY OF IBADAN LIBRARY 4 41 Two main factors interact to govern the fate of hydrocarbons in sediment: firstly, the penetration of oil which is decided by the permeability of sediment; secondly, the power of sediment to retain hydrocarbons, which is often known as Primary Oil Retention. These two parameters are directly controlled by the granulo­ metry of the sediment, in particular by the mean grain size and stability • In region of stable, fine grain sediment with a steady (or predicta­ ble) sedimentation (as in many mud-flats and sheltered subtidal sediments) the hydrocarbon levels may give rise not only to a reliable indication of recent conta mination but a depth profile may give a good recent geochronological record of hydrocarbon input. HO, and Karim (^0) had reported that very fine clay particles bind hydrocarbons so that they are held more firmly than hydrocarbons coating sand (quartz) particle This binding ability was given as being 0.3-1.4 gm oil bound per gm of clay as against 0.03gm for quartz. Other factors exist which affect the fate of hydrocarbons - Temperature has a considerable role to S UNIVERSITY OF IBADAN LIBRARY 442 play, and the amounts of Water and organic material present in sediments exert an important effect. Th-e summary of the total organic extract and total hydrocarbon concentrations determined by gravi­ metric method and the total hydrocarbons determined by Gas Chromatographic method are given in Tables 59 } 60 and 61 for all the samples analyzed in 1984 and 19S5 respectively. 4.8.! LAGOS AND LEKKI LAGOONS The results of the 198'4 samples show that sediment samples in this water .system were contaminated to varying degrees. Lever Brothers' discharge point (845) on Lagos harbour recorded the highest level of total organic extract '1153.Zlpgg”1 as well as total hydrocarbons - S60.21pgg 1 and 95.54pgg gravimetry and GC respectively. • The point had 58.91 moisture content, with fine mud particles. The level of its UCM was high with 80.23pgg ^ and representings UCM has been used as one of the indicators of petroleum hydrocarbons. Okobaba Sawmill (847). also on Lagos harbour ♦ v recorded 202.64pgg 1 (TOE), with total hydrocarbons - UNIVERSITY OF IBADAN LIBRARY 443 .1.5 8.74 (Grav.) and 4 5.48 (GC) . . The moisture content and -.UCM'were 66.11 and 37.65pgg 1 respectively. The * ■* sediment also had fine mud particles.. “ All the other points (except Iwopin 856) also- recorded reasonably hig]p levels of UCM, indicating that these points ais'o must have beep contaminated by petroleum hydrocarbons. Apart from Ibese (851), Iwopin (856) and Epe (857), a l l ’the other points are . within an area heavily stressed because of input of -industrial effluents and on the traffic routes of ship and boats. ' Epe (857) is also noted for fishing by boats which include engine boats, thus the level of hydrocarbon recorded at Epe with the presence of UCM - 18.15 pgg"1 . .The results of 1985 samples 6.20-10.30 -(4.20) pgg ^ (range and mean respectively) compared with 1984 samples .ND - 95.54 (30.33) pgg ̂ (Table 53) did not indicate .any serious contamination. They may be 'regarded as the background levels.* 4.8.2 BENIN RIVER SYSTEM The levels of total organic extracts recorded- for. the points under this river system (60.91-317.08 UNIVERSITY OF IBADAN LIBRARY 4 44 (161,65)pgg-l did not indicate a highly contaminated river system. This was further supported by the low levels of total hydrocarbons with only O.gharife field „effluent canal showing a highly contaminated (Table 53) sediment 42.85pgg ^ . The level of the UCM - 36.90 jjgg -1 clearly indicated .that• the 'canal is contaminated by petroleum hydrocarbon. All the other points can be. said to have recorded the background levels of petroleum hydrocarbon. Points like Robin creek (057), Olaji creek•(835); and Ogharife field discharge pond (o-l) did 'not shove any sign of. - long term petroleum hydrocarbon contamination because they all contain n-alkanes without UCM (Table 53). Absence of UCM indicates presence of biogenic HC in the sediment. • 4.8.3 ESCRAVOS RIVER SYSTEM • Esc'ravos terminal was the only point in 1984 where appreciable levels of total organic extract - 429,01pgg ^ , total hydrocarbon - 178.08 (Grav.) and 64.13 (GC) |jgg were recorded. The point recorded •53.2% moisture and 57.39pgg ̂ UCM, with mud as UNIVERSITY OF IBADAN LIBRARY 445 sediment. Escravos terminal also recorded 294..93 pgg~^ (TOE), 285. 72 and 44.06}.igg ̂ total hydrocarbon b y "Gravimetry and GC respectively in 1985. Nana creek (362) recorded 59.4! moisture, 141.87 pgg"1 (TOE) , 79.85jigg_1 (Grav.) and 10.48pgg-1 (GC), with UCM accounting for 8.16pgg • . Other points sampled did not show any serious, contamination in the i984 and 1985 samples as judged by t-he level of hydro­ carbons and absence of UCM.• 4.8.4 FORCADOS - WARRI RIVER SYSTEM Some points recorded levels of TOE and hydrocarbons which indicated that they were contaminated. Such points are Warri river at.South East of Odidi field (050): 383.4 8pgg_1 (TOE), 377.OOpgg"1 .(Grav.) and 19.52pgg-1 (•GC) for 1984 sample and 114.52pgg ̂ (TOE), 40.10j.igg ̂ (Grav.) and 16.48pgg (GC) total hydrocarbon for 1985 sample, Warri river i:ield (053): 236;37pgg " (TOE), 222.T9pgg ̂ (Grav.) and 30.20pgg ̂ (GC) in 1984; Chanomi creek at confluence of unnamed creek draining Egwe field (858-1): 4 81.48pgg_1 (TOE) , 351.59pgg-1 (Grav.) and 74.05 pgg (GC). Forcados river above Obotobe (865): 415.71 UNIVERSITY OF IBADAN LIBRARY / 446 Hgg (TOE), 384- 71jj£'£ -1 and 33.74pgg total hydro­ carbon by Graviiffictry -and GC respectively. ; Apart from Jaidi ireld (050) ’, only Agbarho (052) recorded values that may be regarded as being above, the background level- The values were 53.57pgg ̂ (TOE), 52.73pgg ^ (Qtav-) and 32.97pgg ̂ (GC) total petroleum hydrocarbon respectively. All the other points (except an unnamed creek draining Odidi field (352), and Warri river above Keremo (863) recorded low levels of- petroleum hydro­ carbon but they all showed the presence of UCM, which may be taken as an indication of petroleum hydrocarbon contamination. , * \ 4.8.5 .RAMOS RIVER SYSTEM This river system was only sampled in 1984. The results indicated that Orughene creek (870). with 58.61 moisture, 641.25pgg ̂ (TOE), 564.05pgg ̂ (Grav.) and -?T.64pgg ̂ (GC) total hydrocarbon had the highest level of contamination- The sediment was a fine mud. Ramos estuary north of Aghoro (038) came in next with 52.7 UNIVERSITY OF IBADAN LIBRARY ON© 447 . moisture, 446. 33yigg ̂ (TOE) , 334.2 7pgg ̂ (Gray.) and 57.32pgg ̂ (GC) total hydrocarbon.- It has clay particles All the. other three points sampled did not give any level to 'indicate serious -contamination. 4.5 .6 NUN - EKQLE - BRASS RIVER SYSTEM i Only 1984 samples were collected and analysed. They all gave levels (range ND - 15.56)(4.83) which may be classified as background levels. The only point with UCM level above lOpgg ̂ was at Diebu creek -off Nun river (043). The results showed- 4 6.31 moisture, 532.79pgg 1 (TOE), 241.69pgg 1 (Grav.) and 15.56pgg 1 (GC) total hydrocarbon. jlr 4.8.7 ORASHI RIVER SYSTEM . • All the points sampled on. Orashi river system in 1984 gave very low levels of hydrocarbon that cannot be anything but the background levels because all the points recorded hydrocarbon levels below lOpgg ^ , ' -although they showed appreciable levels of total organic extracts, this can only be interpreted as being fairly nigh in organic loads that are not petroleum hydrocarbon. UNIVERSITY OF IBADAN LIBRARY 448 In the 1985 samples, only.Qkogbe west (252) recorded values that showed contamination. It has 23% ravisture, 116.52pgg ^ (TOE), 77.2 5 p g g 1 (Gray.) and *Z5...0pgg (GC) total hydrocarbon. All the other samples for 1985 were not quite different from those of 13S4 in terms of hydrocarbon levels. 4.8.8 BONNY'- NEW CALABAR RIVER SYSTEM The only station where more than 10jigg ̂ hydro­ carbon was recorded was Bakana (upstream) #(807). All other points had low level hydrocarbon, with nothing to indicate any serious level of contamination. The 1985 samples were not different because only Umuochi CAhiu) (020) gave 12.52pgg ̂ total hydrocarbon by GC. 4. 8.9 IMP RIVER SYSTEM The three points sampled in 1984 were Kono-water­ side (128), Azumini (Aba) (.813) and Otamiri (817), which gave the following results for moisture content, "total organic extract and total hydrocarbon: Kono waterside, 48.91 3894.34pgg TOE 179.62pgg ̂ (Grav.) and 10.16pgg ̂ (GC) . Azumiri (Aba) - 20.9%, 262.94 UNIVERSITY OF IBADAN LIBRARY 449 (TOE). 40. 25j.igg 1 (.Gray.) and 1.7Spgg 1 (GC) while Otaniri had 18.95, 154.S8pgg 1 TOE, 5.79pgg 1 (Gray.) and" 0 . 30pgg ̂ (GC).. This river system was not sampled in 1SS5. 4.8.i0 CROSS'RIVER - CALAEAR RIVER SYSTEM For 1984 only four points were sampled and analyzed. .These four samples did not show any unusual results. The levels were all below 5pgg ’.But In 1985 , only ■ two samples were collected and analyzed. Cross river east shore (079) recorded a level that was higher than those recorded in 1984. The total hydrocarbon level was 11.34pgg ' by GC analysis. 4.8.1.1 KADUNA RIVER SYSTEM In 1984 four points were sampled, two on the Kaduna refinery effluent canal and two on Kaduna river. The difference was clear because while the two points on the effluent canal, upstreadi (141B) and downstream (14 1A) gave levels of hydrocarbon of 21.52 and 17.10 pgg ̂ respectively. The oth.er two points on Kaduna rwer (843) and Malali (844) gave 0.62 and 9.27pgg respectively. UNIVERSITY OF IBADAN LIBRARY TABLE 59 SUMMARY OF THE TOTAT, ORGANIC EXTRACT AND TOTAL HYDROCARBON CONCENTRATIONS OF LAGOS LAGOON AND NIGER DELTA ■ SAMPLES (GRAVIMETRY AND GAS CHROMATOGRAPHY)pg * _g“^DRY WEIGHT * ! • ' August-September, 1984 January-February, 1985 Code TOE • GRAV. GC . TOE GRAV. GCTHC THC* S THC . THC • ' 1. • LAGOS-LEK•K I1 LAGOON ' • • . 086 119!79 . 94.22 .. 13.47 • * 087 73.01 48.67 • 10.53 • 845 115 3.'70 560.21 95.54 87.96 54.13 •* 2.11 847 202.64 158.74 45 i 48 • < 851 154.94 135.57 23.18 58.99 • 44.24 , 0.20 856 374.37 53.48 ND 857 • .372.17 • 117.07 24.09 127.53 ' 42.51 10.30 • . X 350.09 . 166.85 30.33 91.49 46.96 4.20 SD±154.38 ±73.08 .±13.65' j ±22.85 ±3.87 ±3.37 R - 73.01-1153. 70 48..67-560.:21 . ND - 95.54 58.99-127.53 42.51-54.13 0.20-10.30. 2 . . B E N I N 0 5 7 4 3 . 1 7 • 3 4 . 3 9 • • 3 . 0 0 1 3 4 3 1 7 . 0 8 • 1 3 0 . 2 9 5 . 8 9 V 3 1 1 7 7 . 2 7 1 2 . 1 3 ■ . 2 . 6 7 83.79 17.96 \ 1.02 UNIVERSITY OF IBADAN LIBRARY TABLE 59 (contd) August-September, 1984 . January-February, 1985, Code ■ GRAV. GC GRAV. GC TOE TOE THC THC THC THC • • 347 103.11 • 20.62 2.05 835 189.00 16.08 0.-04 837 128.25 , 102.60 6 . 2 6’, * •838f 252.64 • 176;08 , 9.14 0-1 . 60.91 13.40 . 0.10 ' / 0-2 283.43’ 259.05 • ‘ 42.85 X 161.65 80.52 8.-00 / • SD 28.46 , • 27.44 4.7,6 R ' 60.91 12.13 . ' 0.04 -317.08 -295.05 42.85 j ’ * 3 ESCRAVOS 054 429.01 178.08 64.13 294.93 ' 285.72 44.06 055 919..10 > 22.62 2.30 - 325.56 101.38 7.80 360 123.46 39.83 4.26 \ 362 ' 141.87 79.85 10.48 > \ • 830 247.66 93.09 1.48 831 28.34 13.50 0.91 833 238.92 86.88 1.45 834 . 217.83. i 51.91 0.20' UNIVERSITY OF IBADAN LIBRARY 452 TABLE 59 (contd.) •August-September, 1984 _ January-February, 1985 Code GRAV.TOE GC GRAV.TOE ■ • GCTHC THC THC THC \ ....i - --.... ...... 839 .62.64 24.49 1.49 264.98. 123.80 11.00 X 248.07 59.73 13*.93 264.98 123 i 80 11.00 . SD' 148.46 27.43 ‘ 10! 54 21.55 . 46.76 8.77 R 28.34 13.50 . 0.91 217.83 51.91 0.20 919.10 ‘ -178.08 ‘ •. -64.13 -325.56 -258.72 • -44.06 / FORCADOS - WARRI - 040 65.56 13.11 0.31 . * 47.10 16.19 0.52 049 73.92 38.80 • ,i.3i 88.16 33.34 2.46 050 383.48 . 377.00 ‘ 19.72 ‘ 114.52 40.10 16.48 052 86.90 ■ • 19.72 0.84 r 53.57 . 52.73 32.97 v 053 236.37 222.19 ■ ' 30.22 . 289.79 13.50 0.36 351 47.66 47.66 1.88 92.17 21.22 o.io ■ 352 428.76 304.72 7.17 ' 353 451.47 121.55 2.60 730.62 . 31.77 1.39 37C 589.32 175.17 4.41 • \ . \ 858 481.48 ■ 351.59 74.05 860 268.65 221.80 6.67 123.87 .. , . 41.02 . 6.85' 862 256.58 232.37 4.88 ■ 252.25 30! 63 1.94 063 ■446.84 233.48 5.94 » 864 ■ ?‘*0.82 193.(13 4.41 . / UNIVERSITY OF IBADAN LIBRARY TABLE 4595 3(contd.) Augus t-September, 1984 January-February, 1985 , ' Code GRAV. GC GRAV. TOE GCTOE THC THC \ THC THC 865 . 415.71 . ' 384.71 33.74 866 ' 198.90; 108.24 2.52 54.38 25.10 0.36 X . 29511*5 i90-.32' 12.53 ‘ •' 184.64' 30.56 6.34 SD 169.33 ■ 124.60 19.35 ‘ 24.27 • 3.65' 3.29 R 47.66 1 3 . n 0.31- 47.iO 16.19 0.10 . -589.32 -384.71. ' . ‘ -74.05 -289.79 -52.73 ,-32.97 5 ' . R A MOS’ 038 ' 446.33 334.27 • 37.32 382 512.12 298.74 6.64 869 349.42 . 307.40 • 7.62 • 870 641.25 564.05 71.64 871 ■ . 98.29 8.44 0.12 X 409.48 i-302.58. 24.67 SD 108.59 ■ 111.12 14.30 R 98.29 8.44 0.12 \ \ .. -641.25 -564.05 -71.64 6 NUN - EKOLE - BRASS • K 036 62.73 ’ . 9.07 ND 043 322.79 241.69 15.56 * ’ * . UNIVERSITY OF IBADAN LIBRARY TABLE 549 5 4 (contd.) August-September, 1984 J anuary-February, 1985 • Code TOE GRAV. GC TOE GRAV. GC* THC TH,C THC THC . --- — 281 75.98 6,32 0.32 872 172.08 92.30 4.54 ’ 873 221.59 115.91 3.71 X 173.0*3 93.06 4.83 ' SD ' . 54.01 47.07 3.11 • • • • R 62.73 6.32 ND * -332.79 -241.69 -15.56 0 7 ' • ORASHI t 012 . 11.91 9.53 0.17 013 48.23 30.10 1.87 01'4 200.81 . • 107.72 6.18 -■ 016 279.04 103.68 5.09 021 452.02 227.59 6.18 26.52 21.70 1.58 035 218.37 *13.73- 0.63 . 250 293.94 . 12.78 0 . 1 3 33.20 22v 99 0.12 \ .251 250.48 28.93 1.67 252 451.24 62.37 1.95 116.52 . , 77.25 25. lC 262 365*53 48.91. 1.26 801 47.66 26.91 1.77 18.46 12.30 1.03 1 . I £ /\ UNIVERSITY OF IBADAN LIBRARY TABLE 59 (contd.) August-September, 1984 January--February, 1985 < Code GRAV. GC GRAV. GC TOE TOE THC THC THC THC 802 83.02 61.21 2.78 * 819 24.25 20:24 1.62 4 820 • • 37.38 27.07- 0.36 821 771.40 ' 15.78 ' ■ 0.23 172.71 21.75 0.77 824 ' 263.94 2.14 0.02 / X 266.97 53.67 2.14 • 61.29 29.04 4.37 SD 202.88 61.14 2.17 ' 22.04 9.28 • 3.57 R 47.66 •2.14 . ‘0.02 . 18.46 12.30 0.12 -452.02 .j" r22 7 .59 -6.18 -172.71 -77.25 -25.10 /' 8 BONNY - NEW CALABAR 018 136.48 - . 105.20 8.42 020 110.98 20.74 - 1.25- . 47.13 39.28 12.52 121 300.00 27.27 0.26 .68. 92 18.25 2.81 \ 233 235.98 190.80 8.51 \ 807 1283.44 128.58 21.44 • 84.17 24.94 1.77 808 78.86 52.05 2.15 15.53*' ,12.70' 0.24 1 . 1 • UNIVERSITY OF IBADAN LIBRARY TABLE .59 (contd.) August'-September, 1984 January-February, 1985 Code • GRAV i GC TOE GCTOE G R A V - • THC THC ' THC THC 810 . . 208.88 • 6.43 0.91 • x t 36^.69 .54.31. - 5.75 . . . 70.45 . 40.07 5.15 SD,, ' 200.76 20.36 • 3.53 • • . 24.19 . 18.50. 2.46 * R 78.86 6.43' 0.26 15.53 12.70 0.24 -1283.44 • - -128.58 ' . ' 21.44 -136.48 • -105.20 -12.52 / -S IMP • / • 128 • 3894.34 179.62 • . IQ.16 813 262.94 40.25 1.78 817 134.88 5.79 - 0.30 . X 1430.72 •75.22 4.08 SD 1253.15 59.94 3.29 . R 134.88 f 5.79 0.30 . - -3894.34 -179.62 -10.16 * \ \ 10 CROSS RIVER - CALABAR • 071 54.91 25.31 2.70 079- 49.81 31.13 11.34 210 ■ 181.91 . 9.10'- . 0.05I UNIVERSITY OF IBADAN LIBRARY 457 ■TABLE 59 (contd.). Atfgust-September, 1984 January-February, 1985 • Code 'GRAV. GC TOE TOE GRa V. . GC THC THC THC THC • 811 70.53 9.97 • 0.26 * 812 142.93 12,47 0.52 827 154.00 .42.00’ 4.41 X ' . 105.77 22.44 1 .97* * • SD 24.27 8.01 1 .,04 R 54.91 9.97 0.26 -154.0 * -42.00 -4.41 / / 11 . KADUNA • 141A 232.90 106.09 17.10 67.35 34.29 5.00 ' 141B 534.79 . 171.51 21.52 - 173.25 60.3,8 2.91843 14.86 8.92 0.62 844 72.60 . ' 51.34 -- 9.27 X 213.79 ’84.47 12.13 • SD 129.98. 40.65 5.25 \\ • R 14.86 8.92 0.62 . 1 -534.79 -171.51 -21.52 UNIVERSITY OF IBADAN LIBRARY 458 In 1985 only the effluent canal points were s.ampled -with stations 1 4 1 A a n d 141B recording 5.00 and 2.91ugg 1 ♦ * tot^l hydrocarbon respectively. - 4.8.i 2 IBADAN ’ . ' ' The sample from' Agodp.. garden was contaminated, the value of hydrocarbon was 27.79pgg ^ . • Asejire sample recorded 6.849pgg * total hydrocarbons. Agodi pond is the recipient of refined petroleum products _ J from.domestic sources, mechanic garages, and the 9 -Nigerian bottling company. _ 4.8.13 UT0R0GU - OKPARI RIVER * The samples were collected from three main areas - • impacted swamp (A - G ) , upstream P and R, and downstream CO - J). • . The results of the analysis for the three sampling periods are displayed in Table 60. All the points sampled in 1984 wet season had high levels of hydrocarbon ^vdlth the impacted swamp recording the highest. The • results for the total organic extract (TOE) and total hydrocarbon (THC - by both gravimetry and GC) are 106.95-419.02 (268.69), 73.98-214.05 (136.-39) and 1 UNIVERSITY OF IBADAN LIBRARY 459 51.97-154.06 (95.62.) pgg 1 r e s p e c t i v e l y ' for the • : ‘impacted swamp in 1984 (wet season). Point R (upstream) had 206.64 , 12 7.13 and 115.62 pg/g respectively for the same period. All the points downstream gave an average and mean values of 141.97- 800. 63 (286.46)., 53.05-338.66 (131.59) and 19.5 5 - 24 2.16 (92.78) pg/g respectively. < ; The early 1985 (dry season) samples recorded level far below what was recorded.in 1984 (wet season). The impacted swamp still recorded the highest with an average and mean values of 54.36-491.02 (183.69) pgg ^ - TOE, 17.34-122. 76 (64.07) pg'g ’ - THC.(Grav.) and ND - 6.62 (2.68) pg/g - THC (GC) . ■ The upstream point R gave TOE -. 47.54pg/g, THC (Grav.) - 2 6 . 8 3 p g / g and THC (GC) . - 0.47pg/g. Downstream, the .values were' a bit higher (then the upstream values), the average and. mean values for TOE and THC (Grav. and GC) are 27.35-75.79 (51.12), 19.60-28.89 (24.55) and 0.67-7.96 (2.58) pg/g "respectively. The last set of samples were collected in June- July 1985 (wet s e a s o n ) . ' The values recorded showed an UNIVERSITY OF IBADAN LIBRARY 4 60 .upward trend over those obtained for the 198 5 dry s e a son.(Jan.-Feb.j.. Both the impacted swamp and the . . points downstream had'average results that were “close while the reference (upstream) points had lower results. The results are as follows: * * Imparted styamp - TOE, 42.58-237.28 (106.56) pg/g THC (Grav.), 32.55-177:37 (65.57)pg/g and THC (GC), 2.22-68.06 (22.24) pg/g Upstream - TOE, 31.28-120.57 (75.93). pg/g • THC (Grav.), 14.44-18.36 (16.40)pg/g THC (GC), 2.41-10.22'(6.32) pg/g Downstream - TOE, .30.51-178.27 (94.78) pg/g - THC (Grav.), 23.19-81.50 (42.14) pg/g ’ . . and - THC (GC) , 8.93-52.96 (27.08)- pg/g. The increase in the levels of hydrocarbons recorded during the 1985 wet season over the early 1985 levels . ,-rray be due to run off from land and mixing which allowed 1 * the levels of hydrocarbons in surface sediment to be increased. UNIVERSITY OF IBADAN LIBRARY 461 \ ' TABLE 60: SUMMARY OF TOTAL ORGANIC EXTRACT AND TOTAL HYDROCARBON CONCENTRATION OF UTOROGU SWAMP AND OKPARI RIVER'(GRAVIMETRY AND GAS CHROMATOGRAPHY) pgg-1 DRY WEIGHT October 1984 January-Febrary 1985 Sample . June-July 1985 Wet Season Dry Season Code West Season TOE l’HC (GRAV.) THC (CC) TOE THC (GRAV.) THC(GC) TOE THC(GRAV.) THC (GC) .. IMPACTED SWAMP . . •1 * • ' * A « 126.88 ‘ 71.57 2.22 e 354.64 214.05 . 154.06 ’ . ' 145.04 17.34 6.62 ' 237.28 171.37 68.06 ,c 491.02 ‘ 122.76 1.21 50.43 44.51 ■ 3.61 D 419.02 153.30 126.80 126.90 44,83 • ■ 0.81 42.58 33.62- * 23.76 E 106.95 73.93 31.97 • 54.36 44.83 4.74 ♦V 101.15 90.92 ND . 108.92 33,80 20,29 G 194.14 104,21 69.63 73.24 32,55 15.48 •' 7 268.69 136.39 95.62 ■ 183.69/ 64.07 • 2.68 106.56 65.57 22.24 R 106.95- 73.93- f 31.97- 54.36- 17.34- ND- 42.58- 32.55- 419.02 • 214.05 154.06 491.02 122.76 6.62 237,28 177,37 68,06 U P S T R E A M $ - 1 206.64 ' 127.13 115.62 47.54 i 26.83 0.47 120.57 18.36 10.22 31.28 14.44 2.41 T 75.93 : 16.40 6.32 R 31.28- 14.44- 2,41- * 120.57 . 18.36 10.22 UNIVERSITY OF IBADAN LIBRARY 4 6 2 TABLE ■ 60 (contd.) October i'984 Sample January-Febrary 1985 . June-July .1985 Wet Season Code Dry Season West Season TOE THC (GRA.V.) T1IC (CC) ' TOE THC (GRAV.) THC(GC) TOE THC(GRAV.) THC (GC) | * l • DOWN STREAM \ ' * ‘ f* 0 800.63 ’ 338.66, 242.16 .27.35 19.60 0.70, 63.98 30.72 20.07 N ‘ 245.11 69.65 52.24 . . ’48.59 28.89 1.00 30.51 ■' 23.51 22.64 v • '141.97 • 53.03 19.55 • 118.95 71.14 45,90 M • ■ 83.76 28.83 ‘ 14.68 K 206 • 123.90 92.88 ' 52.73 26.37 0.67 168.46 31.20 / 8.93 T 371.38 118.51 92.02 75.79 23.32 7.96 178.27 81.50 52.96 U 153.21 . 85.76 57.83 50.90' 33.54 .26.69 J 63.43 36.96 24.74 • X 286.46 131.59 92.78 J1.12 24.55 2.58 .94.78 ■ 42.14 27.08 R 141.97-. 53.03- ■ 39.55- 27.35- ,29.60- 0.67- 30.52 23.19- 8.93- ’ 800.63 338.66 242.16 75.79 28.89 7.96 178.27 81.50 52.96 UNIVERSITY OF IBADAN LIBRARY 463 4.8.14 LAGOS LAGOON -(19.85 JAN.-DEC.) The values calculated for the total organic extract (TOE), and total hydrocarbons (THC), the latter by gravimetric and chromatographic methods are given below in Table 61 for all the sampling periods. ■' V T. ^ , * The highest values were obtained in the early wet season (June), TOE ranged from 8.88pgg 1 to 4373.46 pgg 1 with an average of 327.18pgg 1 while the THC levels were 2.08-3554.51 (255.80) and ND - 2766.27 _1 (191.72) pgg dry "weight for gravimetryy and GC respectively. This was closely followed by the April samples writh TOE: 188.83-655.49 .(422.16) pgg \ THC: 122.68-509.18 (315.93),pgg"1 (jGrav. ) and 109.33-42.7^88 (268.61) p g g _1 (GC) . • ' . The results obtained during the February ‘ sa.mpl ing were TOE: 11.61-786.28 (109.61) p g g " 1 , THC: 1.25-695.25 (73.97) p g g”1 (Grav.) and 0.31-539.-29 (56.19) p g g " 1 (GC). December samples gave TOE: 36.35-604.42 (155.08) pgg 1 , THC: 3.02-450.85 (102.62) pgg 1 (Grav..) and 0.25 409.82 (79.87) pgg"1 GC.. UNIVERSITY OF IBADAN LIBRARY 4 64 ‘ ' •October samples recorded TOE: 4 7.6,4-351.23. '(199.44) pgg”1 , THC: 3.S6-222.39 (113.15) p g g”1 Grav.) and ND - 172-.05 (86.03) p g g - 1 (GG). The lowest levels were recorded with the two samples collected in-August, TOE: 60.80-86.69 (73.75) pgg 1 , THC: 9.75-37.57- (23.65) pg g”1 (Grav.) and 0.62-14.64 (7.65) pgg 1 (g c ) . . . : :: : . Be.rger/National Oil/Ijora (LS 20) came out as the most impacted site throughout the sampling period The hydrocarbon levels recorded at this station (by GC).'varied from 14.64 pgg 1 in August 1985 to 2766.27 pgg " i-n «June 1985. Green buoy :££ 3 (LS-7), mouth of Ogun river (LS 13), Okobaba (LS 23), Power Station, Ijede (LS 2 4 ) , -Tin Can Island (LS 19), and Itu O m u‘ (LS -26) recorded hydrocarbon levels between 5'0 and 441 pgg 1 . The highest values recorded were f r o m’ fine, humus-rich sediments (Table 6 1 J . . There is a highly positive correlation between the gravimetry and Gas Chromatographic value shown in Tables 63 and o4 (r = 0.797). UNIVERSITY OF IBADAN LIBRARY 405 TABLE 61: SUMMARY .OP THE TOTAL. ORGANIC EXTRACT ANU TOTAL HYDROCARBON CONCENTRATIONS OP I.ACOS LAGOON SEDIMENT SAMPLES (GRAVIMETRY AND GAS CHROMATOGRAPHY) (1985) (pg g‘l DRY WEIGHT) February April (1) June (2) August (3) October (4) December (5) Grav. GC' Grav. GC Grav. CC Grav. GC GC Grav. GC TOE TOE TOE TOE TOE TOETHC THC m e . THC THC ' • THC THC THC •THC THC THC • LS-1 47.61 34.45 28.15 LS-2 . 19.08 18.13 13.48 % • LS-3 11.61 4.37 . 0.31 118., 19 64.07 . 43.87 •• * LS-4 32.48 1.25 i.15 •’ 13.42 4.98 2.22 . LS-5 49.23 ’ 25.93 30.27 21.52 9.21 0.17 , . LS-6 74.74 24.18 18.65 • 60.64 2.43 ND , / . LS-7 • 264.48’216.10 165.40 • 140.64 107.8i 40j82 . LS-8 76.03 49.71 . 1.63 * * * LS-9 • 5.06 '4:87 4.66 . . LS-10 19.21 13.98 5.19 14.57 6.86 0.41 ' LS-11 41.77 18.09 14 ..90 • 14.91 14.64 8.93 LS-12 12.76 3.83 0.48 LS-13 , ‘ 441.76 339.71 238.81 LS-14 202.05 16.69 1.48 12.91 2.08 0.19 LS-15 58.44 5.64 3.88 LS-16 60.27 40.05 28.10 LS-17. 67.3S 39.97 30.26 60.80. 9.73 0.62 36.35 3.02 0.25 LS-18 39.04 34.75 27.46 47.64^ 3.86 ND 70.38 53.00 9.14 LS-19 75.77 58.00 18.56 188.83 122.68 109.33 .44.51 33.5-6 27.36 V . 42.05 27.80 4.12 LS-20 786.28 695.25 539.29 655.49 509.18 427.88 ■4373.46 3554.51 2766.27 86.69 37.57 14.64 604.42 450.85 409.82 LS-21 50.78 39.61 30.61 , LS-22 68.65 28.33 24.13 47.20 23.48 •20.02’ 79.18 4.65 0.47 LS-23 188.86 148.57 126.32 364.39 282.05 233.79 351.23 222.39 172.05 LS-24 232.75 182.00 148!09 23.70 3.95 0.7I. 98.10 76.42 55.41 UNIVERSITY OF IBADAN LIBRARY 466 TAIILE 61 (Contd .) February April (1) June (2) . August (3) October (4) • December (5) TOE Grav. cc TOE' Grav' GC TOE Grav. GC TOE C-rav< GC TQE Grav. GC. TOE CraVl CC THC THC THC THC . THC THC THC THC . THC THC THC THC ■ • ' | • LS-25 • 52. lV 43.84 42.78 8.88 5.09 1.34 LS-26 !>5.23 • 3.37 * 3t 51 *»• 107.49 95.39 * 59.75 . X 109.16 • 73.97 56.19 422.16 315.93 263.61 327*18 255.8 191.72 73.75 23.65 7.63 199.44 * 113.13 . 86*03 155.08 .102.62 79.87 R ‘ 11.61 01.25 0.31 188.83 122.68 109.33 8.88 2.08 . ND - 60.80 9.73 0.62 47.64 3.86 ND 36.35 3:02 0.25 -786.28 -695.25 ■■539.29 -655.49 -509.18. ■-427.88 ’-43 7 3'. 46 -3554.51 2766.77 -26.69 -37.57 -14.64' -351.23 -222.39 -172.05 -604.42 -450.85 -409.8.2 UNIVERSITY OF IBADAN LIBRARY / 467 4 . 9 OVERALL SUMMARY OF SEDIMENT RESULTS (19,84-85) The overall summary of results obtained from L'agos Lagoon.ana the Niger -Delta area of Nigeria in 1984 and 1985', the Utorogu-Okpari (a case study) , Kaduna (1984-85) and .Ibadan (1985) are given in Table 62. ■ The mean concentrations .of the total petroleum hydrocarbons against the different river systems are shown in a histogram (Figure 36). Looking through the data in Table 62_ vis-a-vis the histogram in Fig. 36, there is really no definite trend as far a s’the petroleum hydrocarbon distribution in, the samples with time (i.e. seasonal variation) is concerned. • What P • appeared to be a higher wet season (1984-) values over the dry season (1985) values in some of the river systems e.g. Lagos-Lekki Lagoons, Renin, Escravos and Forcado-Karri, may be due to" changes in the -lithology of the sample collected in 1985 rather than reflecting -a^'clear-cut h i g h e r■hydrocarbon .levels in 1984 than in 1985 samples. The values recorded during the January to December monitoring o f Lagos Lagoon clearly attest ■ UNIVERSITY OF IBADAN LIBRARY ? 468 to this fact as can be seen -in the distribution graph (Fig, 37) below. Sojae points such' as buoy ^ 3 (LS 7), lkm before Moba village (LS 5), Ijede Power Station “(LS 24) and Island off Palaver St. (LS 25) , recorded dry season figures that ^ere significantly higher than those obtained for the. wet periods. Same can be found at some points in the delta area too e.g. stations 052, 252, and 020. However, certain generalizations can be made on the basis of the results presented in Table 62. Lagos Lagoon recorded the highest level of petroleum h y d r o 4■ carbon at any given period of the study. The results of the 1985 January to December study brought to focus the extent to which the Lagoon has been-, polluted. The high levels recorded may be due to the restricted circulation system of the Lagoon coupled with the high rate of untreated effluent injected- into the- Lagoon system from urban run off and storm water from the rndustrial effluent channels. These factors were further complemented by the nature of the sediment particles found within the lagoonal system, which were UNIVERSITY OF IBADAN LIBRARY 1 4 69 • ' mainly fine clay.and mud with efficient'binding ability which may not allow for easy downward migration of j tlie petroleum hydrocarbons and degradation process may also be very slow. All these would work together to promote the accummulation of hydro’carbons which are hot easily dispersed because of the poor circulation system. • --- • In the Niger iDelta 'area, Escravos', 'Forcados- Warri, Ramos with Benin also recorded appreciable levels of petroleuiiu_hydrocarbons. Althou-gh. the rivers flow through oil activity a r eas\ the results of the analysis in most of the points sampled did not reflect any serious contamination.' Within the delta the points of high petroleum hydrocarbon levels were spatially scattered but most pf them were located very close to petroleum operation areas such as Ogharife (0-2), Escravos terminal (054), Warri river, field (053), Chanomi creek at.confluence of unnamed . ^rfeek draining Egwa field (858), Forcados-river above Obotebe (865), Aghoro (038), Orughene. creek (870) and Bakana (807). Some were--located close to towns and i \ . ' . - i villages such as Umuochi (020) and Dudu town (837). UNIVERSITY OF IBADAN LIBRARY I 4 70 Alaocha (81Q) , Ndoni cr'eek (262) 'arid Obagi field : ‘ • downstream (012) reflect the effect of'.particle sice on -the level of hydrocarbons retained by sediment. They were points located within oil activity area yet very low levels of petroleum hydrocarbons were recorded. This may be because they have coarse sand particles known for their poor adsorptive capacity of oil. They 'also contributed to the 'accelerated rate' of degradation of any petroleum hydrocarbon incorporated into the sediment matrix. The tidal flush may also be a contributory factor. . * The levels of petroleum hydrocarbons recorded for the Utorogu and Okpari samples clearly show that the area was polluted. The effects on the vegetation and the aquatic life was evident during the 1984 sampling trip, the aquatic life in Utorogu swamp was non-existent and the oil was carried downstream with the river flow. The quick recovery of the swamp and the river was quite -astonishing. This may partly be explained by the result of Jenifer Baker (1981) work on the influence of oil industry o n ■tropical marine ecosystem. She came UNIVERSITY OF IBADAN LIBRARY 471 out with a result that biodegradable ar-chemically unstable pollutants will degrade faster in warmer water of the tropics because of the- shallowness and s-aller tidal amplitude of the rivers. The different oxidative processes, especially mi.crobi'al degradation also help to degrade the oil. 'The Ibadan samples also reflected the effect of -urban, activities (e.g. washing of .petroleum products into the water course) on the rive'r's flowing through the city. While Asejire (outside Ibadan).recorded a very low level of hydrocarbons, Agodi garden’s sediment sample gave a result of a point contaminated with fresh petroleum hydrocarbons.. • The Lagos Lagoon study in 1985 brought out a picture of a heavily stressed lagoon where there are lo'calized accumniulation ‘of petroleum hydrocarbons at certain points on the lagoon. Such points are Green buoy t-e 3 (LS 7) , mouth of Ogun river (LS 13), Tin Can Island (off ship wreck) (LS 19)., Berger/Xa,tional Oil/ Ijora (LS 20), and Okobaba (Pylon 134) (LS 23). On the whole the spatial distribution of points with high levels of petroleum hydrocarbon are activity UNIVERSITY OF IBADAN LIBRARY . • '172 TABLE 62: SUMMARY OF TEE DISTRIBUTION OF TOTAL ORGANIC EXTRACT (TOE), RESOLVED AND n-ALKANES, THE UNRESOLVED COMPLEX MIXTURE lUCMj TOTAL ALIPHATIC, ASOMAIIC, TOTAL HYDROCARBONS AND MCiPI* IN SEDIMENTS OF ALL THE VARIOUS RIVER SYSIEUS~SfUDIED EESKEES 1984-85 (pg alA DRY WEIGHT BASIST River No. of IOE Resolved Alkane n-Alkane U C M Total Aliphatic Total Arpirtatic • Total Hydrocarbon NOP I System CommentAnalzyed Range X Range ' X Range X Range X Range X Range X Range X * Range Lagos- 7 73.01- >154.38 ND- 0.90 +0.68 ND- ’ 26.S5 +13.01 ND- 30:33 ‘+13.65 I.ekki 1153.70. 350.09 ND--‘ 1.38 -1.55 4.73 ND- 25 .01 +11.46 91.07 ND- 3.48 + 1.02 95.54 6.6-8.5 Moderately Lagoon 10.84 80.23 7.16 (7.8) * • petrogenic r (15S4) Benin 9 43.17 +44.90 0.04- 0.87 +0.47 0.04- 6.90 +4.58 0.04- 8.00 +4.76 Biogenic (19S4) 317.OS 161.65 >30.43 0.04- 0.98 +0.48 4.24 ND- 5.92 +4.10 41.22 ND- 1.10 +0.25 42.85 -2.7-6.9 to low trace \ ' 4.32 36.90 •2.26 (2.5) petrogenic Escravcs 6 23.34- 284.07 +148.46 0.33- 0.61 +0.13 0.87- 12.42 +9*. 60 0.91- 13.93 +10.54 Biogenic to* (1984) 919.10 1.08 58.45 64.13 low trace 0.56- 1.09 +0.29 ND- li; 34 +9.57 0.04- 1.51 ,+0.94 0.4-9.7 Petrogenic 1.76 57.39 . 5.68 (3.8) Forcados *16 47.66- 295.15 ‘,0.06- 3.25 -5.39 ND- . 8.20 +15.00 0.03- 1.08 +1.37 0.4-7.6 Low trace Warri. 559.32 +169.33 16.19 0.06 2.10 +3.70 53.33 * i C. 28- 11.45 +18.20 3.68 0.31- 12.53 +19.35 ‘ (4.7) Petrogenic (1984) 12.07 69.52 1 74.05 • i Ramos (1984) 5 98.29- +108.59 0.07 -4.02 +1.61 ND- 18.95. +12.19 0.05- 1.69 +0.14 -1.8-9.0 Low trace to ; 641.25 8.06 60.93 4.73 409.48 0.06- 1.33 +0.49 6.07- 22.98 +13.37 0.12- 24.67 +14.30 (5.2) Moderately 2.52 66.91 71.64 ■Nun -Eko le 5 o2.73- 173.03 ND- 0.15 +0,05 ND- ' +2.72 0.55 +0.35 -0.6-7.8 Low trace -Brass 332.79 +54.01 0.26 ND- 4.13 0.12 +0.04 13.61 ND- 4.2 S' ND- +2.76 1.74 ND- 4.83 +3.11 (4.6) Petrogenic (1984) • '.3 0.20 13.82 15.56 \ Oras’nl 14 11.91- 266.97 0.02- 0.50 +0.57 ND- 1.16- 1.56 ND- 0.48 +0.63 -3.2-5.8 • Biogenic (1984) 777.40 +202.97 1.95 0.02- 0.43 +0.50 4.83 0.02- 1.66 +1.62 2.10 0.02- 2.14 +2.17 (1.5) 1.95 5.03 6.18 \ Bonny-New 6 73.86- 370.02 0.24- 1.4 +0.62 ND- 3.68 +2.26 0.02- 0.94 +0.67 -0.9-6.2 Biogenic to Cslabar * 1263.44 +260.76 3.69 0.24- 0.59 +0.12 13.55 «- 0.24- 4.81 .+2.83 4.20 0.26- '5.75 +3.53 (2.5) Low trace (1964) 0.95 17.24 21.44 L«no 1 (1984) 3 262.94 1430.72 0.26- 0.25 +0.10 ND- 3.20 _+2.85 0.15- 0.63 +0.45 . <» -0.3-6.8 Biogenic to 3394.34 +1210.47 0.29 0.18- 0.23 +0.03 8.55 0.25- 3.45 +2.83 1.41 0.30- 4.08 2;3.29 (3.0) low trace 0.27 8.75 10.16 petrogenic Cross 4 54.91- 105.59 0.J2- 0.42 +0.14 ND- 1:36 * +0.84 0..03- 0.19+0.89 0.62 i. 0 4 5 -0.6-4.3 7llv«i - 154.00 +24.77 0.57 . 0.22- 0.40 +0.06 3.35 » 0.22- 1.79 0.26- 1.97 +1.04 (1.5) Biogenic Calabar / 0.47 3.79 4.41(1984) 0.5-5.8 Biogenic to Kadwna J 14(04- 106.7V 0.19- 0.19 +0.21 0 , X % - 0.31 ♦0.12 0.4)- 9.79 +4.79 0.98- 11. 89 +4.64 .1 0/, 0.51 i O . j J 0.62- 12.36 ♦ 6.97 ■ 1 - ■ St i2 t V O • 0.C.4 0.92 20.29 20.90 21.52 (2.6) low trace ♦72.tfl n • petrogenic I I" 1" "111. ' .........■■■■■■ ■■■■H UNIVERSITY OF IBADAN LIBRARY TABLE 62 (coned.) River No. of TOE f Resolved Alkane n-Alkane UCM Total Aliphatic Total Aromatic - Total Hydrocabon v. MOPISamples System Analzyed Range 'X t Range ■ X Range X Range X • - Range X Range X ' Range x Okpari 13 89.12- 0.74- 11.02 +2.53 O'.35- 5.75 +6 35 7.38 79,.30’+55.49 ND- 14.04 % (3.984) 805.00 46.26 24.07 222.90 40.01 267.48 '5.6- Heavy10.2 ; 277.94 — 209.11 Vi * 10.42- 91.76 +64.12 9.90 +11.12 101.66 +7y0.73 (8.1) “ Pebrogenic 241.28 * Lagos- 3 53.999 ' 9 JH.35 91.46+' 0.02- ( i t H l b ) n +71. \ y 15.07 2,76 +3,45 0.02 1,85 1 2 8 3 , 9,52 +2,15 ' ND- 17,05 +15, 62,77 69 0.02- 19,81 +17.62 N O - 0,81 +1.29 0.03 20,62 +18,08 6 3 >95 4,11 * 68,06 2.8-3- 3.8 . Biogenic ' to low ■ (3,3) trace petrogen Ujo* | $ • 0# 202.28 ’ ND- U n i iu n 179.23 9.20 +22,13 ND- 8,66 > 1 ( O M b ) 126.98 2 * S i W 93,63 1352,07 22770033, 383.3.W 'U ±376'00 W - «,09+11,6L 'no- 110,13 +385,58 -2,0 low+607, 70 , • 6 2 , 8 9 2766,?? ~ u,j trace > . . (4 .4 ) petroger tbAdflp n & ,9 t 0.674 1.23 ;0 .7 8 1,22 -° -7 S p ° 7 ( 6 ' W l 15' 59 6*85- 17,32 +14,81 ND- 0,62 +0,88 8,09. 17.94 +13,93 3 .7 -7 .8 Low rr 1 ■ 27' 79 1,24 '27,79 • ~ (5 ,8 ). to *’*i I * • Urine Oil Pollution Index I Moderate•oetrô en UNIVERSITY OF IBADAN LIBRARY UNIVERSITY OF IBADAN LIBRARY 4 75 Hydrocarbon con ce n t ra t i on /-* g g* UNIVERSITY OF IBADAN LIBRARY \ 4 76- • • related', as these points are- either located very close : to oil facilities - oil well, tank farms, flow/pumping stations, refinery, ports, industrial houses or urban settlements. 4.10 PETROLEUM HYDROCARBON CONCENTRATION MIPS The petroleum hydrocarbon concentration maps of water and sediment sample from Lagos.and the Niger Delta are shown in Figures 38 - 45. Figure 38 shows the hydrocarbon concentration (IR) map for.water around Lagos and Lekki Lagoons. .The samples with concentration >5mg/l were mainiy from the points on % the Lagos Harbour. This is the area where most of the vessels berth and some major industries such as Lever Brothers are located around the harbour. Figure 39 is for water samples from points in the Niger Delta. Most of the points with total hydrocarbon concentration > 5mg/l were located on the Escravos and Forcados river 'systems. Other points under this category were scattered in the delta, such as Okrika refinery jetty (233a), Elele Alimini (236), Ahoada (022) etc. i UNIVERSITY OF IBADAN LIBRARY 4 7.7 The maps for the sediment, samples are shown in Figures 40 45. Figures 40, 41 and 42 are for the petroleum hydrocarbon concentrations in sediment around Lagos Lagoon for 19S4 and 1985 (dry and wet seasons) , All po'ints wi-th KC > lOOpg '/g were located around the Lagos' harbour except point 24 (Ijede Power Station).’ Most of the stations showed decrease in the levels of HC in 1985 wet season (June samples). Finally, Figures 43, 44 and 45 showed levels of. hydrocarbons in sediments from the .Niger,Delta area. The points had low levels of 'hydrocarbons' for both the wet and dry seasons. They had what may be referred to as background levels ^< 20pg/g). The maps did not show any discernible trend downstream but the high concentrations were around the activity points. 4.H HYDROCARBONS SOURCE CHARACTERIZATION A number of parameters generated from gas chroma­ tographic analyses have been used’to characterize the \ source(s) of hydrocarbons extracted -from environmental UNIVERSITY OF IBADAN LIBRARY 478 UNIVERSITY OF IBADAN LIBRARY 4 7 9 TOTAL HYDROCARBON C ONC E N TRAT! ON ( BY 1R ) OF WATER S A M P L E S IN THE. NIGER DELTA (1984-8 5 ) LOCATION NUMBERS ARE INDICATED WITH THE CONCENTRATION BELOW (1955 C ONCr EN T R A T IO N S IN BRACKET -( • ) ] I . . ____ i UNIVERSITY OF IBADAN LIBRARY Flg-*M> i Aliphatic hydrocarbon (By GC) of sediment samples around Lagos Lagoon- • Location numbers are indicated with the concentrations'below (June 1385 Concentrations in ^racket - ( • ) •)■ 1984 Station- UNIVERSITY OF IBADAN LIBRARY * 481 • • « UNIVERSITY OF IBADAN LIBRARY t ■. ■I . ' FIG -42: _ TOTAL HYDROCARBON CONCENTRATION (BY G C ) OF SEDIMENT SAMPLES AROUND LAGOS LAGOON. LOCATION NUMBERS ARE INDICATED WITH THE CONCENTRATIONS BELOW [ JUNE 1985 •CONCENTRATIONS IN BRACKET — (o )J . 1984 STATATIONS — Q I , • • • • J M * ' ' UNIVE SITY OF IBADAN LIBRARY UNIVERSITY OF IBADAN LIBRARY 484 / • 3 ' 4 * UNIVERSITY OF IBADAN LIBRARY K . 485 % F IG . 45: * ' ' \ TO TAL HYDROCARBON .CONCENTRATION [ B Y G C ] OF SEDIMENT SAMPLES IN THE NIGER DELTA. LOCATION NUMBERS ARE INDICATED WITH THE CONCENTRATIONS • BELOW [1985 CONCENTRATIONS 4 IN B R A C K E T - ( • ) ] . . te * UNIVERSITY OF IBADAN LIBRARY 486 sample - water, sediments and tissues of marine organisms(260) ̂ Parameters such as high concentra­ tions of an unresolved complex mixture (UCM) of hydrocarbons are often associated with oiled samples. Jones et a l ^ ^ ^ suggest that the UCM 'hump' in sediment sample chromatograms reflects post- depositional microbial degradation of the petroleum- derived aromatic hydrocarbons. The odd/even ratio of n-alkanes calculated as the carbon preference index (CPI) has also been used by several investigators as indicator of the hydro­ carbon s o u r c e ^ ^ 265)^ general, the CPI values of n-alkanes for polluted environments are close to unity. However, an odd/even ratio of unity may not always implicate a curde or refined oil source as a few bacteria also produce alkanes between n-C25 and n-C33 with similar ratios^^^. Phytane is used as a marker compound for petroleum as it is usually absent in uncontaminated samples. The UNIVERSITY OF IBADAN LIBRARY 1 487 ■ pristane/phytane value is also indicator, as a high, value above unity indicate a greater contribution from the biogenic source.. - The major constituents of the n-alkanes. are also very useful as. a source indicator. . tt Some of the.parameters used in the source identi­ fication of the hydrocarbons in the sediment samples analysed are given in Tabies 63-67,' In sediment samples from-Lagos and Lekki Lagoons the CPI Cn-Cj^ -^n-C^) values calculated from the carbon chain length of C^4 - C.,^,-ranged from 1.1 to 2,1. These values indicate the presence of petroleum in the environment. This point' is strongly supported by the presence of phytane. and low values of pr/ph in the samples. The level of deviation- of these values from unity may be explained by the level of contribution . from the C25 ~ C ^ range > with odd-carbon numbered • " n-alkanes within this range contributing significantly tcr^the CPI values. • The major constituents of .hydrocarbons in the Lagos-Lekki Lagoons Were mainly comprised of mixture of UNIVERSITY OF IBADAN LIBRARY ! 488 odd- and even-carbon numbered compounds between n-alkanes in the major hydrocarbons.for- the sediment is 40%..'“ • . . ‘ : • • . In the Delta area, the results also showed wide variations in the- Values- of CPI calculated for the different points*. There were some points that clearly indicated- that contributions of. n-alkanes were only from higher terrestrial plants.(CPI > 3, Boehm 1982), • Such points include Olagua creek/Benin river confluence (838), cPI - 6.6, unnamed creek off Jones, creek (839) CPI 7.1, Bodo creek (121) CPT 3.2 and Uriyama river (812) CPI - 4.4. Phytane was totally absent in these samples and where present the concentrations were l ̂• below 0.001 pgg and no UCM were observed. Sediments from the Delta area also showed similar • * . • n-alkane distribution as was observed in Lagos samples, with the proportion of odd-carbon numbered h-alkanes in the major hydrocarbons as follows: . • Benin (60%) , Escravos (60%) , Fo’rcados-lVarr-i (56%) , Ramos (40%), Nun-Ekole-Brass (65%), Orashi (61%) , Bonny- New Calabar (63%) , Imo (53%), Cross-River-Calabar (65%), Ibadan (50%).? UNIVERSITY OF IBADAN LIBRARY 489 The samples from Utorogu-Okpari river.system and .the Lagos Lagoon.samples (1985) also -exhibited wide variations in CPI values, phytane concentrations Cohere present) and the pr/ph values. The proportion of odd-’carbon numbered n-alkanes in the- major hydro­ carbons of Okpari was 52%, Lagos Lagoon (1985) and Kaduna recorded 54% and 73% respectively. • All these data came, out strongly to.indicate that the n-alkanes were hot purely from petroleum source alone but a mixture from both biogenic and petrogenic sources, that is, the complex assemblage of hydrocarbons in the Lagoon and river sediments indicates two sources, an input of terrestrial plant, (n-C2j .-’C^j - alkanes from waxes of higher plants) which suggest a major sewage input, and input from fossil fuel (UCM).' Urban storm­ water and river run-off'account for most of the input of petroleum hydrocarbons' to the river systems. More research work in the area of petroleum hydro- ^parbori pollution has also resulted in an index equation developed by Payne et al.,;^^^ 268 ancj as jcnown as Marine Oil Pollution Indqx (.MOPI). This equation may be used to compare the relative, magnitude of oil UNIVERSITY OF IBADAN LIBRARY 490 contamination in a series of.tissue or sediment samples. The equation has some component ratios put together, the component ratios are thie UCM/.re solved, even n- alkane/odd n-alkane, and branched.hydrocarbon/n-alkane. These ratios can be used separately or in concert to characterize the1 hydrocarbon burdens in tissue or sediment samples. With each of the component ratios, higher numerical values typically correspond to greater \ . petroleum hydrocarbon burdens. The equation is presented below with the ^indox in Fig. 46. * MDPI = + ^ I EVEN + ^ ^BRANCHED 'HYDROCARBONS ^UCN^^UCM^RESn ] ̂ ODD n-ALKANES where \ UO^j = Unresolved complex mixture in the Hexane fraction in pg/g dry weight of sample. RES^ = Total resolved hydrocarbons in the Hexane fraction in pg/g dry weight. . • ' * i EVEN = Even numbered n-alkanes in pg/g dry weight' ODD = Odd numbered n-alkanes in pg/g dry weight ‘ . N. BRANQ1ED HC = Total resolved HC in the Hexane fraction minus total n-alkanes in Hexane fraction UNIVERSITY OF IBADAN LIBRARY 491 UOk = Unresolved complex mixture in the hexane/dichioromethane : fraction. Interpretation: Subranges of MOPI values between -2 and 15 represent oil contamination levels corresponding to pristine (-2-1), biogenic (0-4), low-level petrogenic (2-6), moderately petrogenic (5-9), and heavily petro­ genic (8-13) conditions respectively. Higher index' values indicate progressively greater hydrocarbon contamination. The. MOPI values for individual sampl-es are listed in Tables 63 -—67 while the range and mean values for the different river systems are listed in Table 62. The MOPI values can be used to further explain the trend indicated by other parameters earlier presented. The samples from Lagos-Lekki Lagoon showed high MOPI values from 6.6 to 8.6, this placed them in the moderately petrogenic zone on the MOP Index. The MOPI values for Lagos- Lagoon are higher than the values obtained for the other river systems in the Niger Delta area. In ranking the other river systems in the Delta area, \ . Ramos river system sediments MOPI values ranged from UNIVERSITY OF IBADAN LIBRARY 492 -1.8 (Muri creek - 871) to 9.0 (Ramos estuary north . ; -east of Aghoro - 058), indicating low- or trace to moderately petrogenic contamination. . Forcados-Warri and Nun-Ekole-Brass river systems MOPI values range between 0.4 - 7.6 and -0.6 - 7.8 respectively, placing them in the low- o.r trace-level petrogenic contamination. Benin, Escravos, Bonny-New Calabar and Imo river systems have MOPI values which place them in the Biogenic to low or trace-level petrogenic contamination zone, while Orashi and Cross River-Calabar river systems fall in the biogenic contamination zone. Cross River-Calabar riA7er system was selected as the' reference area in this study because of the absence of ..oil' activity and low level of industrial activities in the area. Kaduna samples recorded 0.5 - 5.8 MOPI values writh a mean of 2.6 which place it in the biogenic to low- or trace-petrogenic contamination. Not surprisingly enough, the Agodi garden sample on Ogunpa in Ibadan jre'corcled MOPI value of 7.8, input of oil from petrol garages, coca-cola factory, sewage etc., (moderately petrogenic). Asejire sample recorded 3.7 (biogenic to low- or trace-level petrogenic contamination. UNIVERSITY OF IBADAN LIBRARY h 493 On a point to point basis the heavily contaminated points are Berger/National Oil/Ijora (LS 20), Lever Brothers' discharge point (845), North' of NNPC loading •facility (847) all on Lagos Lagoon, ‘'Escravos Terminal (054), and Ramos estuary north east of Aghoro (038) showed values between-8.4 and 11.5 indicating heavily petrogenic contamination. Sediment samples from sampling sites near point sources of anthropogenic or near large settlements which were earlier identified .as contaminated areas, also recorded higher values than sediment from more remote sites. As expected, . sediment samples from Ogharife'. (0-2) , Escravos Terminal (054), Warr'i river field (053), Chanomi creek at Egwa field (858), Forcados river above Obotebe (865) , Orughene creek f870), and Bakana (807), all recorded MOPI values indicating moderately petrogenic contamination. Stations like Muri creek (871), Mbiama C250), Bodo creek (121), Parrot Island (811) and Uriyama C812) showed values for pristine area. All the other stations recorded MOPI vvalues which placed them under biogenic or low-trace petrogenic contamination. UNIVERSITY OF IBADAN LIBRARY UNIVERSITY OF IBADAN LIBRARY TABLE 63;: SOURCE CHARACTERIZATION OF HYbUOCARBONS FOUND IN SEDIMENTS FROM LAGOS LAGOON, KADUNA AND DELTA AREA OF ‘NIGERIA (c o n c e n t r a t io n ps R-lT Oo rcar50 X ( u ' G. rtr~ \ fo o 0l0 t•ri ' O ‘ O' tn O' to t/i to to t-* o to o b to o O O' ’ to SO vO ti-f* g*73 SO -o CO H O Ui O' VD to O X- vO CD p 4̂ H* to -o "-U a> too O too .. ►P >P fO tP P P rP P J 5 tocx too toO toO too ton•Or'> O toN -p- vO O' v5 H* H to X- X~ H* IT vC O' O' tn o to3 to ooJ - fo' P P P to P tn P U .VO ON to tn H O ‘ to o 0p6 to Xto- 0*-3* tx-** ■ Oto Ot-*' co _tn to vC V b CD tn o' to b U> b b H -w r ’ toO too too‘ tP tP nP O o o o a otn H VC o tIoP XP~ OkP' WP \►T>P - so t•no so to txo- too P S' P' p P P~ to* t-o1*O' i P P Tt C—D5 S-* so to o X- to -> 03 to H to to -o to CO 00 CD b vO tn 3 tn tn b a: so p ' ’ ' '— p '— p' '— w ' ’ ’ ' too ioo too . tPo XtP~ onP K° fP P , O O D fi O H-* to -o tn ~ Po -Po t►nP *— t-«oo to 3 to 6 € S P S ' P S ' S 'VD to tn to tn O o 3 O ~o *o O' 1-* tn b tn - e ' ' ■ O o to So h-* o xnP- tsnP -t-Jp tvP o to vO vO v hOP ►o P ✓“N SCO' S ' p tSn' P S ' p ■ / i» X* o 3 to • vO to b to to tn b '-J ■ol l UNIVERSITY OF IBADAN LIBRARY F.SCRAVOS RIVER SYSTEM UNIVERSITY OF IBADAN LIBRARY 1 rH cO r- r~ CM ID in o 4 co r- CO rH CN r" O' CO 00 o v£> vO © d Q, Q, a Q, O, o, O US o m rH vD CO O o cS4 t? d 1 c> a- t? 6 * a* a* r? cy cy CO CM •4- CM CO -4 CO co CM in O' cO d cO • sD \0 CO rH rH d d _, d d d d d Z) d o w OD CO cO 4- rH O' 00 if1 d "1 a 1 ■s1 d" rd1 cT cT d 1* d° d* cd1 co CM CO rH CO CM CO r- O' 4 4 CM CM00 . o «n m cm* co Hi cm CO -4- m di iH *4 rH rH rH TO rH CO rH co m 1 i i vO • o •* * ro l o r~- o co* 2 2 3 vO 1 4- o c O Q O d o O CrMH o o o d d o O rH rH • Z CM• rH 2«5 » — -. CM H 4 rH CM rH rH TH CM rH rHo o O O O O O o O O 1 O • O o d d o d d O o o d o d o o o25 CM CM rH rH iH. rH rH rH rH rH rH * ** Z ON O rH O' O' MO O CO O rH CM vO CO in O' M O rH , CO r~- 2 CO -4 f" <—o lmO v COO OO' OlO 4O- co co rH O' o o00 1 O * .25' • / 2 , \ f *Ec-fj . on rH CM O CM m rcOH O OL'O CCMO 44- mCM VrHO cM o co cm incm -4 0 05 o o • iH o O d o o «H d O d o O O O rH J_> * . 2505 t—*, 3-» -O cH *rd CS O d CO O d -4 rS rd -4o - cs co m o i 4r— Cs*© rOi' CwO r**~■ ’ X 3 I 3 3 n J-t- l̂< 0$ uo> O-OO CrS- CrO- UNIVERSITY OF IBADAN LIBRARY ' *> - » .. i •..* -.vftftNMKk 499 TABLE 63; (contd.) SONM Stn at.ion Code n-alkane MOP I ^ X14 Pr Ph Pr/Ph Value * Five Major Constituents %C25-33 j ' R 0.15 68.3 • 1.0 0.001 0.001 0.62 0.5 -0.52 ' 1-86.6 -2.7 j -0.68 -5.8 r ** IBADAN i Ag-1 0.67 17.8 . 1.0 ! - - - 3.8 C20(15.0), C19(12.0), C17(10.5), CjgftO.O), ^ 2(09.0) AS-2 . 1.78 69.7 1.6 - - * 2.8 C31(12.6), C29(11.a ), C^do.8),. ^ ( 09.6), C25(07.8) X 1.23 •* 43.8 1*3. - . - . - ' . . 3.3 R i 0.67 17.8 • _ - % - . -1.78 1.0-69.7 -1.6 2.8 .1 . - - “ , A3.8 • ♦ __ L____ / ♦ UNIVERSITY OF IBADAN LIBRARY '500 TABLE 64: SOURCE' CHARACTERIZATION OF HYDROCARBONS FOUND IN SEDIMENTS FROM UTOROGU.SWAMP AND OKPARI RIVER (OCTOBER 1984) SN StationCode n-alkane % MOPI C25-33 ’CPI14 Pr ' Ph Pr/Ph •Value Five Major Constituents X 1 B 24.07 76.9 1 .0 - - V 7.2 CS6(25,9)>' C?5(25.4), C24(22.4), C27 ( * 2) t CzrC09-9) 2 D 1.59 6 6.8 1 . 2 0.031 0.079 0.39 1 0.2- 'C26(48.2), C24(l3.6), C22(08.8), C29(07.O), C27(05.8) 3 E . 2.96. 96.4 1 . 6 - - ' "7.2 C2,(72.2), C25(07.6), C32(05.3), C27(04.5), . 'C28(02.6) 4. G-l .. .4̂ 48 83.8 1 .6 . - - - 6.7 C26(22-7)> C27(l3.4) C28(l2-4)2- 0 25(1 1 .2), C29(10.2) 5 •G-2 ■ 4.42 75.7 ’ 1.4 0.008 0.002 4.00. 6 .8 g26(-30.1), c27( 1 0.0), C25( 09.4), C2g( 09.3), C29(07.1) 6 G**3 ’4.92 67.3 1 .6 - - - ' 7.4 C26(33-3). C24(3i.5), C25( 18.4), C2/ 15.0), C 20( 0 1-2) 7 G-4 ‘ 9.21 68.7 1.4 - - - 8.4 • C26(-28.9)', C24(24.9), C25( 20.7), c27( 17.i), C20(04.9) X 1.38 76.4 1.3 '0.006. 0 .0 12 0.63 7.7 * R ' 1.59 66.8 1.0 ND ND ND 6.7 -24.07 -96.4 -1 . 6 '-0.031, -0.079 -0.63 rlU.2 8 * R-l . • 3.02 87.9 4.5 ’ 0.060 0.028 2.14 8 .2 c 25( ^ . d , C31( 13.4), C32Cl0.9', c 27(io.o), *24 06.4 ) ‘ 9 R-2 1.73 75.0 1.9 0.017 0.039 0.4/+ 9,9 Cil(24-.5\ c% (i2 ..a), C21(08-8), C25(08'-8), c29('a8.D 10 R-3 ' ■ 0.97 74.2 1 .6 - • - • 9.6 . C25.(34:99, C26(14..6), C2 7(12.5-), c 28,(Qa_93, C20(07.9) x ‘ 1.91 79.0 2.7 0.03 0 .0 2 0.86 9.2 R 0.97 74.2 1 .6 ND ND ND 8 .2 • -3.2 -87.9 -4.5 -0.06 -0.04 -2.14 -9.9 * 1 1 0 -1 11.97 83.0’ 1.4 ' 0.079 0 .0 57 1.39 _ 8.7 C26(35.5), C2 7(I2,7), C3 1(10.5), C29(09.J2), C 24(Q8.7) - 12 0-2 9.28 93.4 ■ - 1.5 .0.193 0.042 4.60 8. 8 C2&C'34,3), c?5,C2A4) > C27.C 3-5.-0), C29(.23.-0) t C 24(C3.2) 13 •N 0.33 50.5 1.7 0.015 0.006 2.50, '9.2 C25(19.4'>, C23(13.8), C27.U3.5>V c26<13*2), Q2 1<11.7; . 14 V . ' 0.72 85.6 1.3 - 7.2 C26(59.4), C25(Q8.6), C24(06.0), C29(06J0), 15 K-l 1.32 69.6 1.4 . - - - 5.6 C26(39.6>, c24(3o.4);‘ C27(15.1), C j/IS.S), c 2a(oi.i) 16 K-3 • . 16.22 46.5 ' 1.3 - - - 8.7 C24(48.8), C2e(23.1), C25(LI.8>, C27(09.1), C28•, <22(16.7), Cjo (L4.4 ) » 2̂8 ) > 2̂9 ̂ 6.2 ) 1 1 0 -2 0.009 92.5 1.4 0 . 0 0 1 . 0 . 0 0 1 2.69 1.4 C 29̂ 16.4 ), <27(l4.0), <3 1 (1 3 .7 ), <26(l3.5)> <28 <09.8 ) 1 2 0-3 .0.378 . 04.1 3.3 - 2.7 <26 6 6 .8 ), C32 0.8 .1 ), • <23 9.5.7 ), ^ ( 3 5.5 ), <50 (33.0 ) 13 N 0.029 ■ 98.3 2 .8 ' 0 . 0 0 1 - - 3.3 C2 5(39'.2), C32(16.6), C2g(12.3), C2?(07.3), C24(07.3) 14 ' K-2 0.034 67.1 1 . 2 0 . 0 0 1 0 . 0 0 1 4.00 3.1 CjgttO.i), C2 6(10.2), ri9 (1° ‘V ’ ?2 1 (1Q ‘0)» £75 (M*0 ) 15 T 1.134 32.5 1.4 - - - 4.7. ’ C21(40.9), C2 2(21.0), C26(17.5), C25(08.4), C27(06.7) XR 0.27 7327..6 , . 10.. 0131 5 1..85' 0N. 0D0 1 0 . 013.30 ND- 0 1 1.N3D4- 13.98.3 . 04 - 0 . 0 0 1 0.001 4.00 4.7 . * • S . . I I- • ,.. I *«- ■* • v— • "vw'-ni — ----<• ............• • ■ '-WIJ UNIVERSITY OF IBADAN LIBRARY 502 TABLE.66: SOURCE CHARACTERIZATION HYDROCARBONS FOUND IN SEDIMENT FROM UTOROGU SWAMP AND OKPARI RIVER (1985 JUNE! t SN StCoadteion n-alkane % ' C25-33 • LCFPAI1^4 Pr Ph Pr/Ph MV0aPl1ue Five Major Constituent? % * \ IMPACTED SWAMP \ 1 A-l 0.13 85.0 1 .0 ND" 0 .0 1 - 4.3 ' C26(19‘6)>’ C27(13.1), C.29 (11-3), C28(H,3), C25(10.3) 2 B -1 .0 1 70.8 1 .2 0 .0 1 0^01 1 .0 9.1 C2s(12.1), .c26(ii.o), C27(10.3), c30(°9-4), C31(09.3) 3 C-2 • 0.*09 73.4 1 .0 • ND ND - 5.2 C25(31.7),‘C24(26.6),:C26(18.0),: C27(̂-2.7) f C29(06.4) 4 C-3 0.24 47.4 0.6 ND ND - " 5.2 C24(45.6), C25(27.3), C26(07.7), C23(04.7), C28(04.-0) 5 D 2.94 49.9 0.6 ND ND - 5.8 C24(48.6>, C25(28.0), C’26(12.9), C21(07.7), C20(01.3) . 6 F 2.40 46.9 0.4 ND ND - 6.2 .' C24(50.2), C2s(22.3), C26(17.4>, C27(07.2), C2q(02.9) 7- G-l 1.16. 82.2 1 . 1 ND ND 6.0 C27(l4.9), C26(l4.4), C2g(l2.7), C25(11.3), C29(10.7) // 1 UP STREAM P 0.06 67.5 0.5 ND • 8 ND1 - 5.3 C26(i4.4). C2?(l2.7), C25(ll.8X, C28(11.5), C24(10.2) 9 R-l 0.02 89.0' 1.5 • ND • ND 3.0 C25( 37.5), C24(33.6), C26(11.9), C27(08.8), C28(0 1.8) _ 10 R-2 3.27 84.5 -0.5 .0 .01 o.oi 0.2 6..0 C24(41.8), 0^(31.5), C26(16,5), C27(05.5), C2q(0 1.8) 1 1 R-3 0.25 44.0 0.9 ND ND - . ' 4.8 C30(25.4), C32(24.6), C31(17.4)\ C26(14.3), C28(07.3) . I UNIVERSITY OF IBADAN LIBRARY ■ 503 . TABLE 6“6 (contd.) ------ ----— SN Station.Code .n-alkane % i C25-33 Pr • Ph Pr/Ph MOPI < < Value Five Major Constituents % DOWNSTREAM * \ . * 12 0-1 ‘ 0,28 ' 69.8 • 1.0'• ND ND - \ 7.3 C 27^30.4',, • C (19..9), C (l8.0•>* c (n.3), C^(03.l'1 .• 1 3 ' 0-2 24 25 ' 26 . . 30 2.A5 70.5 1.8 * ND ND -J. , S.7 C 31(12.5), C (12.2),- . 27 • C 20 (10.6), C (10.1),29 C (09.2)r 25 14 .0-3 ■1.73 81.4 .1.6 0.01 0.01 ' 0.7 6.1 C24(20.2), C25(19.2), C29(11.3), C26(09.1), C27(06.3) 15 , N 0.55 68.9 • '1.2 0.01 6.01 0.4 .7.5 C2-5(52.5), C24(22.0), C26(09.0), C27(08.1), C20(03.2) 16 V .4.65' 72.5 1.0 0.01 . 0.03 o’.i 6.8 C29(19.4), C27(14.2), C26<12-‘>'-' C3](09.9), C2s (08.8) 17 • M 1.39 70.2 1,4 'o.oi •1 0.01 . 0.2 ' 5.5 C 26 (42.9•), C 25(ll.o), c 27(09.6), C 24(08.6), c 20(05.9) 18 K-2 0.95 93.5 Of. 4 ’ ND ND “ 5.9. C2$(33.6), C26(29-o)» C27(09.6), C29(09/6), C28(06.8) 19 T \ 3.29 \ 73.4 '1.9,. 0.04 0.14 0.3 '7.2 C24(38.2), C25(l9.8), C2^(l6.6)> C19(i5.4), C27(07.7) 20 U .3.15 81.4 ■ •0.7 0.01 0.01, 0.7/ 6.3 - C25(51.-3), C24(19.3), C26C09.9>, C7?(06.9), C19(03.4) 21 •J-l ' 0.45 75.3 1 .0 ND 0.01 - 5: 2 ■C25(35.3), 'C24(25.l), C26(20-5)’ C 7(l2.0), C2g(04.0) 22 j-2 2.14, 63.5 1.0 0.01 0.02 0.1 ' • M C26(29-’3)’ C27(l4.0), c 25(i3.6), C29(09.2), C2g(08.l) 23 J-3 9.51 55.4 0.6' 0.01 0.01 1.0 6.4 C26C32.7), C25(ll.8>, c ?7(i i .o ), C24(08.0), C28(07-6) • 1 \. » ' * \ UNIVERSITY OF IBADAN LIBRARY TABLE 67: SOURCE CHARACTERIZATION OF HYDROCARBONS FOUND IN SEDIMENTS FROM LAGOS LAGOON (1985J I ; " ~ Nation ., % Code- 11 a ' ane CP1 4̂ , Pr ■ Pr/Ph Valuc Five Major Constituents % •1 ,LS-i ” 1.928 23.7 ■ 5 .1 . r - 5.9 ^23 2̂ 2 . 8 ) , ^ ( 2 2 . 4 ) , Ĉ 5 ( l 2 . 0 ) , ^ ( 1 1 . 6 ) , C27(08.2) 2 LS-2 0.404 52.5 1.4 - . - 6.4 C21( 2 7 .2 ) , C2 0 ( 12 .4 ) , C27X11.8), C2 6 ( 1 0 .4 ) , C30 (09.4) 3 LS-3 0.306 - 41.8 1.-0 - ' - - .-0..4 C24( 2 9 .4 ) , .C2 3 ( 20 .2 ) , C28( 1 5 . 6 ) , C25 ( 1 3 . 8 ) , C27 (12.4) 4 LS-32 '4.590 67.1 . 0 .8 0.036 0.040 0.90 6 .6 C1 8 (1 1 . 0 ) , c3 0 (i o . o) , c3 1 d o . o y , C28( 0 9 . 6 ) , C2q(09.4) 5 LS-4 0.912 20.8 7.1 - 1 0.5 Ci g (31 .6) , . C23( 30 .8 ) , C2 1 ( 1 0 . 8 ) , C25( 0 8 . 6 ) , C28(05.8) 6 LS-42 1.722 74.8 1 . 2 * ' - - - 0 .2 C23( 28 . 4 ) , C20(19.O), ’ C29( 1 5 .0 ) , C28( l l - . 4 ) , C30(11.2) 7 LS-5 1.034 63.1 1.2 - 0.008 - 6.3 C25( 2 0 .0 ) , C28 (14 .4 ) , C30( 1 1 .2 ) , C23( 1 0 . 4 ) ,. C29(09,8) 8 LS-52 . 0.162 80.2 - - - 7 -1 .6 C31( 3 3 .3 ) , C29( 2 5 .9 ) , C27( 2 1 .0 ) , C21(12.3). , C18(07.4) 9 •LS-6 i:310 64.7 . 1\4 - - 1 .6.0 C29( 2 1 .7 ) , C25( 2 0 .6 ) , C20( 1 7 .3 ) , C28( 1 3 . 0 ) , C26(07 .2) 10 LS-62 ND. ' ND ND ND ND ND'' C ( - ) , c ( - ) , c- ( — C ( — ) , C ( — ) 1 11 . LS-7 7.150 • 33.2 • 1.2 0.158 0.088 1.80 ■8.4 C25( 3 3 .8 ) , £8 ( 2 0 .6 ) , % ( 1 8 .3 ) , C21( 1 2 . 0 ) , C19(06.5) 12 LS-72 33.816 - - - - - 5 .1 C24( 5 2 .8 ) , C22 ( l 6 . 8 ) , C20( 1 5 .7 ) , C23( 0 8 .2 ) , C21(06.4) 13 LS-82 1.400 6 5 . 4 , 1.3 - - ‘ 1.2 C29( 2 8 . 4 ) > C25( 1 0 .7 ) , c28( i o . i ) , C24( 1 0 . 4 ) , §6 (09.7) 14 •LS-92. , 4.168 82.4 1.9 _ ‘ - - r ‘ 2: x C25( 4 0 . 3 ) }- C28( 1 4 .7 ) , C21( 07 i9 ) , C28(07,.9)', C27(06.9) 13 . LS-10 4.820' 78.5 - - - 1 . 9 C25( 7 8 .5 ) , C22( 0 7 .9 ) , C23( 0 7 .3 ) , C2q( 0 6 .4 ) , C ( “ * ) \ 16 LS-102 .0,406 • 92.1 - - i - 0 .7 C29( 7 4 .4 ) , C26( 0 8 .9 ) , C27(08.9y, C20( 0 7 . 9 ) , C ( — ) 17' LS-11 0.818 54.3 1.6 0.002 0.036 0.06 5:9 C21( 2 6 .9 ) , C25( 1 3 .9 ) , • C28( U . 5 ) , C32( 1 0 . 3 ) , C31(09.0) UNIVERSITY OF IBADAN LIBRARY 505 liLli ft 7 (contil.) SN Station n-alkane < %Code , 34C25-33 CPIS Pr Ph Pr/Ph MOPI Value Five Major Constituents % 18 LS-112 1.076 43.1 1.3 - - - 4.8 '’ S i < 2 2 . l ) , c 2^1 0 . 8 ) , ^0814 ) > S 9 ( 0 7 .6 ) * S o (°7>4 ) 19 LS-12 _ 0.438 53.9 0.9 - - - 0.1 Cjo ( l 5 . l i c 2^1 2 . 3 )* S o S 1 . 9 )*» S 7 ( l0 . 0 ) 20 LS-132 40.222 ' • 91..6 6.7 • -• - ** \ 7.1 ‘ i 5 ( 4 2 .8 ) , ' C2y ( 3 9 .4 ) , S 8 (0 5 . 4 ) , S o (0 3 . 2 ) , S 8 <00.9) 21 LS-14 1.446- 100.0' 1.0 . - - • 1.2 . S 8 (20.7). , S 9 a s . 3 ) , S o (1 4 . 8 ) , S 7 (1 3 . 1 ) > S 6 a ° . D 22 LS-142 0.186 100. Q - • •- - -1 .7 *■<29 4*5 '» ■ • 23 .LS-15 3.880 11.4 2.8 - - - ■ 1.7 S 9 (46.9 ) , S o (L3-9 ) > S 3 Clo. o ) , S i (06.9 ) , .C18 (06.5 ) 24 LS-16 6.682 64.8 ■ 1.8 - - - 5.2 S 5 <50.3 >, S o (23- 7 ) » S g (10 .5 ) , S 4 ( 0 9 .7 ) , S g (0 2 . 2 ) 25 LS-17 0.652 . 50.7 1.5 0.012 0.028 0.43 7.7 C25 (L'3.8 ) , ' S 6 (>-3.5 ) , S 9 CL2.9), S 3 CL2 . 0 ) , S.7 a o . i ) 26 LS-173 0.552 86.2 1.2 - . - - -2 .0 S i a s . 8 ) , S 9 (14-9) , a 2 0 -3 . 8) , 030 0-2.0 ) , q>7 X) , Ci9 ( 0 6 .8 ) , 35 •LS-20 28.842* 15.9 1.0 0.140 0.466 0.30 9.9 S.o (20 . 9 ) 1 S i ( 2 1 .2 ) , S 9 (11.7 i S 2 (07.7 ),, C26 (O7 *8 ) 30 15-201 8.454 • 34.1 1.6 0.572 0.316 1.81 10,3 0 25(3 7 . 6 )* S 2 ( 2 0 .4 ) , S i (12.7 )\ S b ( ° 7 • 7 ) * C20 (07-S) 37 LS-202 126.978 . 1.6 9.848 12.546 0.7B 1 1 . > (^9 (24 . 2 ) , c:L7 (16.4),, Cj5 ( 1 6 . D , S 4 ( 09 .5 ) , C2Q (08.6 ) UNIVERSITY OF IBADAN LIBRARY O O H ci"4 5U0 TABLE 67 (contd.) SM ■ Station Code n-alkane % MOPI C25-33 CRlJJ Pr Ph Pr/Ph Value Five Major Constituents % \ ' 38 LS-203 0.402 41.8 0.5 ' . . 7 .1 : CL8(34.8>, ^ ( 13 . 9 ) , ^ ( 0 9 . 5 ) , Ĉ g (07 .0), C29 (06.5 > 39 • LS-205 11.232 • 16.5 1.6 0.282 0.362 0.7? '10.0 (^5 (1 7 . 4 ) , 0̂ ( 16 . i , c21 (15 . 5 )’> ^ ( 14 . 1 ) , c ,2 (io ;6 ) \ 40 IS -21 2.282' 20.3 3.3 - 0.146 6.1 9̂ 9 (39.4 ) , 2̂5 921 (1*6.9 922 9i0 (05*5 ) 41r LS-22 i : i 2 0 . 26.5' 1.9 0.012 0.032 0.38 6,. 5 9^ (23*4), G2^(l4,.l)> Cj_g(l2.9)> C^g(ll.,l.)> Ĉq CoS.O) 42 LS-22 1.364 • 41.5 1.4 0.010 0.020 0:50 6.1 C31( l3 .8 ) , <̂ 5 (1 1 . 6 ) , C20 (08.9 ),_ C2 1 (08 .5), 677(08. 1 ) 43 LS-225 0.256 . 28.9 1.8 - - 0.3 Cj1 (33.6) j C2 0 (28 .9 ), C25 ( l3 .3 ) , C ^ fo S ^ ) , 6, 7 (08. 6 ) 44 LS-23 6.154 41.6 2.5 6.388 0.616 0.6.3 ■' 8.0 *̂25 (43.1) > 921 (l4*2), Ĉ g (12.3 ) > ^ 9 (08. 2)5 9>6 (05.3 ) 45 ' LS-232 40.164 89.0 2.4 0.280 0.668 0.42 7.4 (25 (41.4) > (07.2) , 9>6 (07.1) > (g2(65*8)> C2]_(^5*6) 46 LS-233 ND- -' ND ND ND . ND . - .47 LS-234 6.854 89.3’ 14.1 - - 8.3 075(53. 9 ) , 975(35. 5 ) , 077(05. 1 ) , 073(04. 1 ) , 075(0 1 . 3 ) / 48 LS-24 16.270 ' 31.4 • 2.4 0.070- 0.154 9.45- 7.5 9 ^ (40.5 )} ( l l • 7 ) > (22 (̂07*6 )} C20 (07*3 ) } 932^^*^^ 49 LS-242 0.170 - 0". 7 - . 2.0 (-74(37. 6 ) , ^ ( 1 7 . 6 ) , C20 (17.6), C2 1 (12 .9 ), C23(09.4) 50 LS-245 4.394 • 56.3 1.8 0.008 0.026 0.31 is. 8 075 (23 .9 ), C2 1 ( l 2 .7 ) , C70 (07 .9), 075(07. 7 ) , 6j2 (07.3) 51'. LS-251 20.170 47.8 1.0 - - - • 5.0 C21(41 .6 ), C26 (29 .6 ), 037(06. 6) , 077(03. 8 ) , 073(03. 2 ) 52 LS-252 0.756 _ 33.5 0.9 - - 1.6 025( 27. 3 , 673(25. 1 ) , 075(18 . 0 ) , 077(1 1 . 6) , 670(10 . 8 ) 53 LS-26 2.378 68.9 1.6 - . “ 1 - 1 .2 923(25*3 ) , 927 (24.4) > 9̂ 6 (2^.6 )} C30 (06 .8), 922(05*8 ) 54 LS-262 3 6 . 1 1 6 72.2 5.9 - - - 4.7 079(48. 3 ) , 075(20. 8 ) , 073(13 . 4 ) , 070(03. 0 ) , 077(04. 9 ) \ UNIVERSITY OF IBADAN LIBRARY 507 • MOP. INDEX • ■ ~ 3 | .2~| -1 i 0 I 1 T ~ 2 ! 3 I 4 | 5 ~ ] 6 I 7 1 8 I 9 I 10 111 H 2 1 U H E A V I L Y PETROGE NiC MODERATELY PETROGENIC LO W TRACE PETROGENiC BIOGENIC PRISTINE - 3 1 - 2 1 - 1 | O j l [ 2 ] 3 ) 4 | 5 i 6 | 7 | ft 9 j 1p | 11 j 12 | 13 / . , Fig. 4 5 : Descr i p t i on of the Marine Oil Po l l u t i on Index (M OP I ) / . v r * ^ UNIVERSITY OF IBADAN LIBRA Y 508 All the methods of source identification used so far are never used in isolation and should not be considered absolute quantities, but they should be interpreted in conjunction with other environmental data (e.g. sediment grain size, organic carbon, proxi­ mity to anthropogenic hydrocarbon sources, etc.). Several investigators^^9) cauti0ned against indiscri­ minate use of component ratios as a means of identify­ ing petroleum contamination. Biogenic, fossil, and industrial sources of hydrocarbons may contribute to a UCM in sample chromatograms, and they may affect ratios of odd:even n-alkanes, ratios of unresolved to resolved components, and ratios of the isoprenoids pristane and phytane. There are possible sources of UCM other than human activities. UCM is synthesized by some anaerobic non-photosynthetic bacteria^^ and green algae, Chlorella valgaris ̂ . Bacteria and green algae such as chlorella spp. are widely distributed in natural environments. Page et al.^^^ reported that biodegraded mangrove UNIVERSITY OF IBADAN LIBRARY 509 leaves contributed to the UCM in extracts of near shore sediments that had not been contaminated with fresh petroleum. In addition, unburned coal is a potential source of resolvable lower molecular weight n-alkanes, isoprenoid, and aromatic compounds, as well as poly­ cyclic aromatic hydrocarbons (PAHs), to marine sediments and deposit feeding organi• sms ( 2 7 2 - 2 7 4 ) Contribution from these and other soruces can be diffe­ rentiated by high resolution GC and GC/MS techniques. The chromatograms shown below illustrate some common features in petroleum hydrocarbon analysis. Tigs. 47 and 48 are examples of petroleum contaminated sediments, with a smooth curve distribution of n-alkanes (no odd-carbon predominance) and the presence of UCM, they are both weathered but Fig. 48 showed oil heavily weathered than Fig. 47. A mixture of petrogenic and biogenic is indicated in Fig. 49, while Fig. 50 showed a bimodal distribution of n-alkanes, which suggest a mixed input having a varied boiling point range UNIVERSITY OF IBADAN LIBRARY 510 .The distribution pattern of the hydrocarbon of • some representative sediment samples are shown in Fig. 51. Some of the samples showed the presence of pristane and phytane. The samples showed different stages of weathering - disappeararice of the lower hydrocarbons and majority of the samples have prominent' peaks between and ; Under hydrocarbon source characterization, it is pertinent to mention that the petroleum hydrocarbons present in some of'the samples may be from different sources su’ch as crude and refined oils. The results of individual hydrocarbons present in the analyzed samples made it difficult to have an easy classification' because most of the samples have carbon range between n-Ci? and n-C^^. Crude oils have .n-alkanes covering this range while refined oils have hydrocarbons over narrower boiling ranges than the corresponding crude oils as dictated by refining processes. This point ■"is clearly expressed in the chromatograms* of some Nigerian crude and refined oils shown below Figs. 32^60. v UNIVERSITY OF IBADAN LIBRARY UNIVERSITY OF IBADAN LIBRARY UNIVERSITY OF IBADAN LIBRARY UNIVERSITY OF IBADAN LIBRARY UNIVERSITY OF IBADAN LIBRARY 515 Il UN Percent compositionIVERSITY OF IBADAN LIBRARY UNIVERSITY OF IBADAN LIBRARY 517 c„ .p chromatogram of Bonny medium. UNIVERSITY OF IBADAN LIBRARY . 4 UNIVERSITY OF IBADAN LIBRARY UNIVERSITY OF IBADAN LIBRARY Fig. 55: GC ChremGtogram of Nigerian Diesel Oil (Refined) (n-Cin*n*C,,) . V ✓ UNIVERSITY OF IBADAN LIBRARY 3 : G C C h r o m a t o g r a m o f A u t o m o t i v e G a s Oil t R e f i n e d ) ( n - C 1 2 C 2 4 ) . UNIVERSITY OF IBADAN LIBRARY 522 UNIVERSITY OF IBADAN LIBRARY 523 . f UNIVERSITY OF IBADAN LIBRARY f f % i / r. UNIVERSITY OF IBADAN LIBRARY 525 It is safer therefore to assume that the petroleum hydrocarbons might be mixtures of both refined and crude oils in some of the samples, especially in samples from the refinery channels, industrial areas e.g. Lagos Lagoon, and points close to large settlements. 4 . i 2 WEATHERING OF PETROLEUM IN THE AQUATIC ENVIRONMENT IN THE STUDY AREAS "Weathering" of oil in the aquatic environment pertains to that collective set of processes which alter the chemical composition of petroleum through evaporation, dissolution, photochemical oxidatio© microbial degradation, and auto-oxidation. The physical processes mediating the chemical changes are mixing, emulsification, and sorption (11,265) Incorporation of petroleum into the sediment usually results in accelerated weathering of oil in oxygenated substrate, mainly through microbial degradation^^’ . ppe gtoss effects UNIVERSITY OF IBAD N LIBRARY 526 of these processes on the chemical composition of oil can be predicted ( 4 5 ’ 2 4 4 ) . S'o me ’ i*n dicator pa‘r ametercs have been used to determine the weathering age of oil in the aquatic environment. These include the ratios of IJCM to the total n-alkanes, 1JCM to total resolved, the UCM (long-term) to the sum of n-alkanes from n-C^ to n-C22 ( ^2 1 - ^ 3 ~ recent hydrocarbon intro­ duction). The n-alkanes are more susceptible to degradation than the isoprenoid, acyclic, and aromatics, as the weathering age of the oil increases, the values of the ratios increases due to decrease in the amount of n-alkanes left in the oil. Isoprenoid hydrocarbons are generally more resistant to bacterial degradation than the n-alkanes, thus the ratio of phytane and its neighbouring n-alkane, C^g, is provided as a rough indication of the relative state of biodegradation in samples. The ratio of pristane and n-C^y can also be used although the pristane has contributions from both petroleum and biogenic sources. UNIVERSITY OF IBADAN LIBRARY The results of these parameters for the analyzed sediment samples are shown in Tables 68 to 72.• These results indicated that the samples were contaminated .with heavily weathered oil because the low-boiling n-alkanes have been.lost in most samples, the n-alkane up to n-C-̂ g have b'een. lost as can" be seen in Fig. 48. The .ratios -given above involving the UCM and n-alkanes increased with increase weathering rate because n-alkanes are preferentially -lost.. The Pr/nC-^- and 'Ph/nC^g ratios also increase with t-he weathering age of the oil as n-alkane' are eliminated faster than the isoprenoids.. Some samples showed the presence of fresh oil from the carbon range in their chromatograms and the low values for the weathering ratio (i.e, UCM/n-alkanes UCM/ Examples of such sample are Lever Brothers' 'discharge point (845), Asagha (134), Jones creek (360), Chanomi creek at confluence of unnamed creek draining Egwa field (858), Orughene creek (870), ' "Bakana (807) , Port Harcourt harbour (2 33a.) , Umuochi (020) and Berger/National 0il/Ijora (Stn 20 Lagos Lagoon). ' - UNIVERSITY OF IBADAN LIBRARY \ 528 • TABLE '68: - n-ALKANES AND. UNRESOLVED COMPLEX MIXTURE (UCM) PARAMETERS OF SEDIMENT SAMPLES FROM LAGOS, NIGER DELTfi, KADUNA AND IBADAN AREAS OF NIGERIA Recent Long term*. SN Code n--alkanes 'Total Pr Ph' UCM Total %' UCM . • UCM Alkanes recentResolved n-C17 n-C18 Aliphatic Resolved n-alkanes Resolved r23 • UCM n-C14 „ r23 n"C14 i LAGOS -LEKKI LAGOONS . . • .1 , 086 0.28 ■' 0.35 0.98 1.46 , 10.22 1.0.57’ • . -3.31 • •36.50 29.20 , 0.C4 255.50,087 ' . 0..10 0.22- 0.55 9.19 9-.41 • .2.34 91.90 • 41.77, 0.02 . 459.50 8,45 4.73 . 10.84 ' ' 3.49 4.23 . 80.23 91.07 11.90 • 16.96 7.0) 1.92 j 847 0.56 . 0.67 10.73 23.84 41.79 .37.65 38.32 1.75 67.23- 56.19 2.36 0.31 121.451i' 851 0.45 0.70 6.99 • 19.34 20.04 3.49 42.98 27.63 ' 0.14 138.14 . . 856 ' - - - • _ _ _I 857 0.16 0.39 0.66 1.95 18.15 18.54 2 :1 0 • 113.44 46.54 0.08 . ’226.88 j 2 BENIN j • • ■ 057 1.20 1.79 .0.14 0.21 ’ -| 1.79 100.00 _ . 0.80 134 0.86 1.11 17.24’ - 3.21 4.32 25.69 3.73 \2.89 0.19 16.89 • 311 0.15 ' 0.16 . 0.98 0.28 1.83 1.99 8.04 ■ 12.20 ll .44 ' 0.02 91.-50 • ' 347 0.06 0.06 0.24 0.27 1.08 1.14 • 5.26 ,18.00 18.00 0.01 108.00 .» 835 C.04 0.04 0.47. 1.10 0.04 100.0 - - 0.01 - 837 0.96 0.99 .13.32 - 3.01 4.00 • 24.75 3.14 3,04 0.10 30.10 1 838 • 0.28 0.28 7.23 7.51 3.73 25.82 25.82 • Q.07 103.29 1 i *■ ♦ 'l UNIVERSITY OF IBADAN LIBRA Y S 29 TABLE 68 (contd.) • Recent Long term; SN Code n-Alkanes Total Pr Ph UCM Total UCM UCM Alkanes RecentResolved n-ci7 n-C18 Aliphatic Resolved n-Alkanes• Resolved nr, r UCM _C1234 nn-rci234 • ; 0-1 0.08 0.08 0.73 0.36 - 0.08 •100.00 _ _ 0.05 _ 0-2 4.24 4.32 57.91 126:95 36.90 41.22 10.48 . • 8.70 ' ' 8.54 1.58 23.35 3 ESCRAVOS 054 • . 0.47 1.06 6.34 0.35 57.39 • 58.45 1.81 122.11 54.14' 0.16 358.69 1 [ 055 • §338 1.76 - - - 1.76 IDO. 00 ~ V * - 0.10 “ • 360 1.08 ■ ’1.20 0.12 0.85 2.46'/ 3.66 . 32.79 • 2.28 2.05 0:21 11.71 362 0.33 0.56 • 1.69 . 3.31 8.16 8.72 6.42 24.73 14.57 ' 0.08 102.00 •831 . 0..52 0.87 2'.63 _ - 839 0.86 1.06 0..87 100.00 1 _ _ i 3.67 . 1.46 •• 1.06 100.00 0.07 0.06 p A ' •FORCADOS -WARRI • i . 040 0.08 0.08 0.25 0.18 O'. 20 6.28 45,57 2.50 2.50 0.01 20.00 * 049 • 0.08 0.14 - - 0.97 ■ 1.11- 12.61 12.13 \\ 6.93 - , {050 10.03 • 15.84 . - • - - . 15.84 100.00 - 0.64 052 0.17 . 0.18 - 1- 0.45 0.63 28.57 , 2.50 0.08 0.08 5.63 053 0.73 K04 1.88 ' 4.19 26.64 27.68 3.76 36.49 ' • 25.62' 0.08 333.00 351 0.09 • 0.13 1.09 1.61 1.50 1.63 _ 7.98 16.67 11.54 0.05 ■ 30.00 '352 2.62 6.65 2.88 3.58 - 6.65 100.00 - - 0.98 - 353 0.14 0.15 0.52 . 1.54 2.30 2.45 6.12 16.43 15.33 p.03 76.67 \ V • • • ' j, v \ r * ■ r-"*T -rj ■ : t . / f . ' r UNIVERSITY OF IBADAN LIBRARY TABLE'68 (contd,. )• Recent Long term Code n-Alkanes Total Pr • Ph UCM Total X UCM UCM Xlk,anes Recent Resolved n-C.^ n-C18 Aliphatic Resofved n-Alkanes Resolved n-C2j UCM-14 n-C2314 372 1.15 . 1.22 0.75 0.37 2.95 4.17 29.26 2.57 _ 2.42 ' 0.31 76.67 858 12.07 16.19 7.05 8.42 53.33 69'.52 ' 23.29 4.42 3.29 1.08 49.38 860 0.21 0.26 - - 4.64 . 4 .*90 5.31 ' 22.10 17.85 0.05 92^80 •862 0.09 0.56 0.85 4.27 3.76 4.32 12.96 31.78- ■ 6.71 0.03 125.33 863 2.71* 5.52 1.4-6 6.61 5.52 100.00 • - - ' 1.43 r 864 0.25 0.31' - “1 3.75 4.06 7.64 .15.00 .12.10 0.03 125.00 865 • ' 3.10 • 3.68.' • - . 0.42 28.76 / 32.44 11.34 9.28 7.82 0.95 30.27 866 • 0.06 0.06 - - 2.00 • 2.06 2.91 33.33 33.33 0.01 200.00 RAM0£ - 1 038 1.63 8.06 .‘‘•1,69 1.05 27,04 35.10 22.96 16.59 3.35 0.13 . 208.00 382 2.52 5.81 0.19 0.17 — ’ 5.81 100.00 - - 1.74 869 ' 0.07 \ 0.19 v • 0.70 6.80 6.99 2.72 97.14 35.79 0.02 340.00 870 2.-35 V 5,98- 2.42 5.37 60.93 • 65.91 8.94 25.93 ,\ 10.19 0.98 62.17 871 0.06 0.07 “ 0.07 100.00 0.01 - " ■NUN-EKOLE-BRASS ! • 1 036 _ _ ’ . / ■\ r*r' • / UNIVERSITY OF IBADAN LIBRARY 531 TABLE 63. (coned.) Recent Long term'. Code n-Alkanes Total Pr Ph UCM Total % UCM UCM Alkanes RecentResolved n-Ci? n-C18 Aliphatic Resolved n-Alkancs Resolved „23 UCMU-C14 n-C2314 043 0.19 0.21 13.61 13.82 1.52 • 71.63 .64.81 0.03 - 281 0.20 0,26 0.61 6‘.64 - 0.26 100,00 ■ - - , 0.08 - 872 0.07- . • 0,12 - - 3,79 3,91 3,07 54.14 31.58 .0 .0 1’ 379.00 873 ' 0,15 ' Q, 16 * , 3,24 3,40 / 4.71 21,60 20.25 0.01 324.00 0 R A*S H I • • / 012 0.16 0.17 - - 0'.'17 100.00 0.09 013 0.20 0,20 0..37 0.12 1.05' /j 1.25 16.00 5.25 5.25 0.04 26.25 oi4 1.09 1.23 0.93 ' 0.77 2.85. •• ’ 4.08 30.15 2,61 ■ 2.32 0.59 4.83 016 1 Q.4‘2 0.47 5.62 0.28 3.41 3.88' ’ 12.11 8.12 7.26 0.18 ' 18.94 021 0,20 0.20 - - 4.83 5.03 3.98 - 24.15 24.15 0.02 241.50 035 0,56 ' • 0.58 0.37 0.14 ' - ' 0.58 100.00 - - 0.14 - 250 0,13 0,13 0.74 0.44 _ 0,13 100.00 0.05 _ 251 0.07 ■ 0.08 _ 0.37 0.14 1,56' 1.64 4.88 ' 22.29 \' • 19.50 0.02 78.00 252 1.95 1.95 0.74 ‘ 0:44 - 1,95 100.00 - 0.17 - 262 0.32 0,32 '0.38 ■ 0.14 0.63 • 0.95 33.68 1.97 . 1.97 0.15 4.20 801 0,44 1.25 - - - 1.25 100.00 - - 0.21 802 0.25 0.25 1.07 0,61 1.90 2.15 11.63 7,60 7.60 0.09 21.11 . I \ m : ■ 4 UNIVERSITY OF IBADAN LIBRA Y TABLE 68. (contd.) ' Recent Long te.riai SN ' Code n-Alkanes Total Pr Ph ' Total 1 UCM UCM Alkanes •Recent . • Resolved n-Ci? UCMn-C18 'Aliphatic Resolved n-Alkanes Resolved „ r23 UCMn-C14 r23 C14 , i 821 . 0.16 0.16 0.74 0.61 _ 0.16 100.00 .. „ ‘ 0.05 _ 824 0.02 0.02 - ■ ■ - - 0.02 ' ' 100.00 ' - 0.00 - 8 1 BONNY - NEW'CALABAR 4 ' / * 020 0.48 0.87- - - . ' 0.34 , 1.27 71.90 0.71 0.39 0.14 2.43 . 121 0.24 0.24 0.49 " 0.28 - Q.24. .100.00 - - 0.02 233a 0.55 0.55 0.86 0.55 6.76 ‘ v 7.31 7.52 ' 12.29 12.29 0.12 56.33 ‘ 807* 0.95 3.69 0.85 0.80 13.55 17’.24 21.40 14.26 3.67 0.13 *104.23 808 0.45 . 0.59 0.99 0.28 1.41 2.00 29.50 3.13 2.39 0.13 10.85 810 0.87 0.88 - * “ - 0.88 100.00 . - 0.21 j\ 9 IMO ~ " • i . f1 128 _ 0.18' 0.20 0.05 0.03 8.55 , 8.75 2.29 47.50 \ 42.75 0.06 142.50 813 0.27 0.29 - 1.06 1.35 21.48 3.93 3.66 0.15 7.07 817 ' 0.24 0.25 0.37 0.14 - 0.25 100.00 ' - . - . v 0.12 - . / 4 ♦ / * . 4 ' UNIVERSITY OF IBADAN LIBRARY 533 TABLE 68: -(contd.) Recent Long term; ' SN Code n-Alkanes Total ?r Ph UCM Total Z UC.M UCM Alkanes Recent Resolved n-C17 n-C18 Aliphatic Resolved n-Alkanes Resolved „ r 23 UCMn_C14 „ r23 n_C14 . — " 10 CROSS RIVER - CALABAR • * • 071 0.47 ‘ . 0:57 0.48 1.60 '2.10 2.67 21.35 4.47 3.68 0.28 - 7.5 • 811 0.22 ■ * ’ 0.22 0.74 , 0.44 - 0.22 ■ 100.00 - . - 0.04 812 0.46 0.46 2.97 0.22 - . 0.46 .100.00 - / 0.10 - 827 0.44 0.44 0.34 0.28 3.35 • 3.79 11.61 *7.61 * 7*. 61 0.03 111.67 * 1 11 KADUNA ‘ * • 141A 0.25 ' 0.25 0.13 0.06 20.25 20:25 1.22 81.00 81.00 0.06 337.50 141B 0.84 0.84 16.26 • 17.10 4.91 20.36 . 20.36 0.24 71.25 843 0.15 0.15 0.36 0.22 0.43 0.58 25.86 2.87 2.87 0.04 . 10.75 • 844 0.52 0.64 ' 0.14 0.22 8.56■ 9.20 6.96 16.46 13.38 0,06 142.67 12 IBADAN * \ Ag-1 0.67 0.67 27.12 27.79 2.41 40.48 V 40.48 0.52 52.15 As-2 1.78 1.78 - 5.07 6.85 25.99 , 2.85 2.85 0.40 12.68 . / ¥ *■ * I UNIVERSITY OF IBADAN LIBRA Y ‘53-1 TABLE 69: n-ALKANES 'AND UNRESOLVED COMPLEX MIXTURE (UCM) PARAMETERS (OKPARI RIVER) (1984) Recent Long-term; SN Code n-alkanes Total UCM Total % UCM alkanes recent (ug g_i) UCMResolved Aliphatic Resolved n-alkanes . Resolved r23 UCM n-C14 „ n “ Cr 1243 i: ■ B 24.07 28.78 85.27 114.05. 25.2 3.5 3.0 0.164 * 520.0 2. D 1.70 2.27 103.63 105.90 2.1 . . 61.0 . 45.7 0.311 333.2 3. •. E 2.96 3.18 ' 23.19 26.37 12.1 ' 7.8 7.3 0.079 293.5 4.- G-l 4.48 5.24 37.38 42.62 12.3 ' ■ 8.3 7.1 • 0.383 97.6 4 5. G-2 ' 4.43 4.81 35.53 ■ 40.34 ' 11.9. 8.0 . 7.4 0.809' 43.9 6. G-3 . 4.92 12.55 39.32 . 51.87 ■ 24.2 8.0 -3.1 0.058 677.9 7. 0 4 9.21 • ■ 21.53 102.56. '• 124.09 , 17.4 11.1 ■ 4.8 0.631 162.5 8. R-l 3.11 8.31 86.42 94.73 ' 8.8 27.8 10.4 0.172 . 502.4 9.' R-2 1.79 3.27 148.46 151.73 • 2; 2 82.9 ■ 45.4 0.391 379.7 10. R-3 0.97 2.11 91.01 93.12 2.3 93.8 43.1 0.229 . 392.4 11. O l 12.10 18.38 222.90 241.28 / 7.6 ■ 18.4 . 12.1 0.992 ■ 224.7. . 12-. 0-2 9.52 26.14 150.66 202..93 12.9 15.8 5.8 0.312 482.9 . 13. N 0.35 0.74 44.00 44.74 1.7. . 125.7 59.5 0.149 295.3 141 V 0.72 3.89. . 11.06 14.95 26.0 15.4 2.8 • 0.061 181.3 15. K-l 1.32 . 3.04 . 7.38 10.42 29.2 5.6 • 2.4 - - 15. K-3 16.22 . 46.26 99.76 146.02 31.7 6.2 2.2 0.757 131.8 17. T . 4.89 6.54- 83.38 89.92 7.3 . 17.1 12.7 0.54 153.8 18. U . 0.76 1.23 55.45 56.68 2.2 73.0 45.1 ^ •0.221 250.9 • - \ . / t * / r UNIVERSITY OF IBADAN LIB ARY . 535 * TABLE 70 n-ALKANES AND UNRESOLVED COMPLEX MIXTURE (UCM) PARAMETERS (OKPARI RIVER, FEBRUARY 1985) Recent Long-terraJ SN Code n-alkanes Total Total recent X UCM UCM alkanes UCM Cpg 8-1) Resolved UCM Aliphatic Resolved . n-alkanes Resolved nn _rC2134 ,.23 n " C14 j1Xj • Bi-i • 0.053 0.064 7.336 7.40C 0.9 138.4 114.6 0.045 163.9 2. B2-l - 0.085 0.093 2.135 2.228 4.2 ■ . 125.1 23.0 0.006 385.4 3. ■C-l ND ND ND ND ND ND ND ND ND 4. D 0.055 0.058 0.467 0.525- 11.0 8.5 • 8.1 • 0.005 94.3 5. El-1 •0.362 0.373 2.369 2.742 -0.1' • 6.5 • 6.4 0.085 . 27.8 6. =2-1 0.255 0.316 .5.741 6.057 5.2 22.5 18.2 ' 0.084 68.1 • 7„ F ND ND ND ND j ND ND ND ND •ND 8. . K-2 .0.034 00.38 0.577 0.615' 17.0 15.2 . 0.009 65.7 9. N 0.029 00.32 0.693 0.725 4.4 23.9 21.7 0.001 1474.5 10. 0-1 0.011 ' 0.013 0.244 0.2257 5.1 22.2 18.8 . 0.001 369.7 11. .0-2 0.009 • 0.009 0.134 0.143 6.3 * 14.9 14.9 0.001 418.8 12. 0-3 0.373 0.378 0.703 1.061 35.0 , 1.9 1.9\ 0.059 11.9 13. R-l ’ ND • ND . ND . ND ' . ND ND ND \ 1© ND 14. R-2 0.175 ’ 0.272 0.562 0.834 32.6 3.2 2.1 0.002 231.3 15. T 1.134 ’ 1.134 6.947 8.081 ' 14.0 6.1 6.1 • 0.740 9.4 . I y UNIVERSITY OF IBADAN LIBRA Y i—1 o 536 TABLE .71: n-ALKANES AND UNRESOLVED COMPLEX MIXTURE (UCM) PARAMETERS (OKPARI RIVER, 3RD SAMPLING) * i Recent .Long-term n-alkanes Total Total % UCM • • UCM alkanes recentSN Code (}ig g- 1 ) Resolved UCM- Aliphat ic Resolved UCMn-alkanes Resolved n r 23 . \ . n“C14 n r 23 ° “ C14 1. A-l 0.131 0.131 2.091 2.222 5.9 16.0 16.0 0.012 174.3 2. ' B 1.014 1.138 _ 62.766 63.954 ' 1.9 ' 60.9 52.8 ■ 0.232 - 270.5 3. C-2 0.091' 0.116 2.830 . 2.946 ■ 3.9 31.2 24.4 •ND - C-3 0.242 0.275 2.379 3.154 8.7 11.9 10.5 0.017 169.4 5. D 2.933 4.066 15.016 19.0/82 21.3 5.1 3.7 ’ 0.054 . 333.7 6. £ 2.404 3.880 ■ 14.468 18.348 21.1 6.0 3.7 0.070 206.7 7. G-l 1.155 1.‘184 14.165 15.349 7.7 12.3 ■ 12.0 0.095 - 149.1 8. J - l 0.454 0.454 - 5.988 6.438' 7.0 ' 13.1 13.3 0.066 90.7' 9. J-2- 2.136 2.628 , 12.565 ■ 15.193 17.3 5.9 ■ 4.8 0.061 206.0 10. J-3 9.505 15.072 33.007 48.079 31.3 3.5 2.2 0.269 122.7 11.' K-2 . 0.951 1.167 7.760 8.927 13.1 8.2 6.'6 0.026 298.5 12. M 1.387 3.476 11.205 14.681 23.7 8.1 3.2 0.059 189.9 . / f UNIVERSITY OF IBADAN LIBRA Y 537 TABLE 71 (con td .) Recent Long-term * SN Code n-alkar.es recent Total UCM Total % UCM UCM alkanes UCM (pg g- 1 ) Resolved Aliphatic Resolved n-alkanes Resolved n r 23 23 n C14 n “ C14 13. N 0.545 0.841± 21.798 22.639 ■ 3.7 39.9 25.9 0.122 178.7 ' 14. 'OtI 0.282 ' 0.958 . 13.488 14.446■ ’ 6 . 6 . ' 471,8 14.1 0.028 481.7 15. , 0-2 2.453 5.113- 16.999, 22.112 23.1 6.9 3 .3 ' 0.185 91.9 16. 0-3 1.726 1.844 20.58C ' 22.424 8.2 11.8 ' 11.2 0.181 113.7 17. P 0.060 0.061 11.929 1.990 ' 3.1 32.2 ,31.6 0.014 137.8 18. R-l 0.016 0.021 - 0.021 100.0 - - 0.002 19. R-2 3.274 ' 3.358 21.384 24.742 13.6 6.5 _ 6.4 0.302 70.8 20. R-3 0.249 0.556 3.115 3.671 15.1 ' 12.5 5.1 0.044 . 70.8 21. T 3.288 4.824 47.. 750 52.574 9.2 13.8 9.9 0.238 200.6 22. U .3.145 3.358 , 23.332 26.690 12.6 7.4 ' 6 .9 0.585 39.9 23. "V 4.649 8.861 . 37.035 . 45.896 19.3 8.0 4.2 v 0.110 336.7 ♦ ♦ i i i ’ - UNIVERSITY OF IBADAN LIBRARY TABLE 72: n-ALKANES AND UNRESOLVED COMPLEX MIXTURE (UCM) PARAMETERS LAGOS LAGOON (1985) SN Code, n-Alkanes Total Pr P’n Long-term Resolved ' n-Ci- UCM Total % UCM Recent n-C18 Aliphatic Resolved li”-Alkanes Aikanes recent UCM nr- CC2134 n r23 n-C14 1 . LS-i • 1.928 1.928 - - 21.878 23.806 8.1 11.348 1.410 • . 15.52 •2 LS-2’ 0.404 0.574 ' - - 11.211 11.785 4.9' 19.531 0.178 62.98 ' , 3 LS-3 0.306 " 0.306 - - - 0.306 100.0 - '0.088 - 4 LS-32 4.590 , 4.666 • - 0.08 33.582 38.248 12.2 7.197 . 1.398 24.02 • 5 ’ ' LS-4 0.912 ' 1.154. - - - 1.154 100.0 . - 0.714 /. 6 LS-42 1.722 2.222 - - 2.222 100.0 - 0.434 - 7 . LS-5 1.034 1.324 - 0.31 15.832 17 . 15 6 7.7 11.958 0.328 48.27 8 LS-52 0.162 0.170 - - - / ' 0.170 100.0 - • 0.032 - 9 LS-6 1.310 1.540 - - 15.074 .16.614 9.3 9.788 0.386 '39.05 10 LS-62 ND ND - - ND ND. - - - - 11 LS-7 • 7.150 7.296 ' 1.41 0.06 124.604 131.900 5'. 5 17.078 4.258 29.26 12 LS-/2 33.816 25.124 - - - 25.124 ' 100.0 - - ' 15.950 ■ - 13 LS-82 1.400 1.630 . - - -1.630 100.0 - 0.344 - 14 LS-92 ' 4.168 4.660 - ■ - 4.660 100.0 - ■ . 0.660 - 15 LS-10 4.820' 5.192 - - - '■ 5.192 100.0 - n1.038 - 16 •LS-102 • 0.406 0.408 - ' - - 0.408 100.0 - 0.032 . 17 LS-11* 0.818 1.198 0.11 .1.38 11.304 12.502 9.6 '9.436 0.378 29.90 18 LS-112 1.076 '1-.260 - . 7.150 8.410 - 15.0 5.675 0.416. ' 17.19 . / ✓ UNIVERSITY OF IBADAN LIBRARY TABLE 725 3•9 (contd..) SN Code 'n-Alkanes > Total Pr Ph Total % UCM Recent Long-term Resolved UCMn~C17 • n-C18 Aliphatic Resolved n-Alkanes Alkanes recent n r23 * UCM n_C14 n — _ _ _ n _rC1243 19 LS-12 0.438 0.484 0.484 100.0 0.160 __ 20 \ LS-132 40.222 43.596 - 0.13 163.964 207.560 21.0 3.761 2.416 67T87 21 LS-14 1.446 1.476 - - - . 1.476' 100.0 - - - 22 LS-142 0.186 0.186 - - •0.1&6 100.0 - - - 23 . LS-15 ' -3.880 3.880 - - - 3.880 100.0 " . 3.400 24 • LS-16 6.682 7.596 20.504 23.100 27.0 • 2.699 1.704 12.03 25 LS-17 - 0.652 0.792 0.67 2.8 28.424 29.216 2.7 35'. 889 ' 0.312 91.10 '26 LS-173 0,552 0.624 - - - 0.624 ‘ _ 100.0 - 0.066 ’ - 27 LS-175 0.254 0.254 - - 0.254. ; 100.0 - O.CoO - 28 LS-18 1.706 2.046 =- - 22.788, 24.834 8.2 11.138 0.936 24.35 29 LS-184 ND - T - ' - - - - - - 30- LS-185 6.180 8.299 :;b.07 0.08 - 8.299 100.0 - - 4.846 - 31 LS-19 14.940 18.553 - - - 18.558 100.0 - . 2.392 - 32 .LS191 5.152 5,830 0.87 0.42 89.400 95.230 6.1 15.33,4 4.546 19.67 •33 LS-192 0.722 . 0.722 22.728 23.450 3.1 31.479 0.520 43.71 34 LS-195 4.094 ■ 4.116 - - - 41116 100.0- - 1.060 - 35 LS-20 . 28.842 29.868 0.39 0.50 488.722 518.59 5.8 16.363 \ 23.114 21.14- 36 LS-201 8.454 ■ 9.342 - ■ 0.49 387.360 396.702 2.4 41.464 5.002 77.44 37 LS-202 126.978 179.226 0.47 ' 1.58 2524.154 2703.380 6.6 ■14.084 114.920 21.96 38- LS-203 0.402 0.804 - - 11.966 • 12.770 6.3 . 14.883 0.234 51.14 . / i UNIVERSITY OF IBADAN LIBRARY 540 TABLE 72 (contd.) » Long-term J SN Code n-Alkanes ’Total Pr Ph Total % UCM Recent recent Resolved n-Ci? UCM Aliphatic Resolved n-Alkanes Alkar.es n-C18 • U’CM„ r23 n'C14 nn _rC2134 39 LS-205 11.232 11.876 0.18 0.20 381.526 393.402 3.0 32.126 8.810 • • 43.31- 40 LS-21 2.282 . 4.336 - 1.43 23.920 > 28.256 • 15.3 ' • 5.517 1.748 13.68 41 LS-22 1.120 1.574 0.18 0.26 20^764 22.3-38 7.0 13.192 0.764 27.18 42 LS-222 .1.364 ' 1.914 0.31 0.24* 17.304 19.218 10.0 9.041' 0.718 24.10 43 LS-225 0.256 0.466 - ' - - 0.466 100.0 • - 0.096 - ’ 44 ' LS-23 .6.154 10.564 2.28 0.81 101.742 112.306 9.4 • 9.63. •2.968 34.28 45 LS-232 40.164 41'. 112 1.40' 2.39 174.010 215.122 . 19.1 4.23 4.00 43.39 46 LS-233 n d ‘ ND - - - ND . • - - - _ 47 LS-234 6.854 ‘ 6.854 - ■ 152.446 /159.300 4.3 22.242 0.646 235.98 48 LS-24! 16.270 17.494 0.7.1 0.51 • 120.390 . 137.884 12.7. 6.882 11.374 10.58 49 .LS-242 0.170 0.710 — ‘j - - 0.710 100.0 - 0.106 - 50 LS-245 4.394 5.518 0.31 0.42 44’. 470 49.988 11.0 8.059 1.560 28.51 51 LS-251 20.170 20/170 - - 19.000 39.170 51.5 0.942 10.496 • 1.81 52 _ LS-252 0.756- 1.338 - . - ' - 1.338 100.0 - 0.278 - 53 LS-26 • 2.378 3.510 - - - 3.510 100.0 - 0.740 - 54 . LS-262 • 36.116 59.748 - - - 59.74 --J__________________8_____________ 100. o' - 9^\.474 • - • I » ‘ - UNIVERSITY OF IBADAN LIBRARY 541 These ratios have also been used for source identification of the hydrocarbons present in sediment sample.s. As earlier indicated under ;the MO PI section, higher numerical values of these ratios is a pointer to the presence.of petroleum hydrocarbons. i - 4. ]_3 ACCUMMULATION OF PETROLEUM HYDROCARBONS The levels of petroleum hydrocarbons- in water column most of the time reflect recent introduction of the hydrocarbons into the aquatic environment because the resident time for hydrocarbons (e*g. alkanes and 1ight ' aromatic} in "water is relatively short. The physical and chemical processes, (e.g. f. current, temperature, chemical and microbial degrada­ tion) would always act to eliminate the hydrocarbons. The insoluble fractions; (alkanes^ and' some aromatics) are taken down to the bottom sediment to .be incorporate in the sediment matrix. The ratio of the’hydrocarbon concentrations in the two compartments is a good indicator of the pollutional trend. Some results are shown in Table 73.', below' to illustrate this point. UNIVERSITY OF IBADAN LIBRARY 542 The concentration/ . factor can c'orrectly reel::' if ihe introduction of petroleum hydrocarbons has r:e: on lor a long period, the nature of the sediment in terrs of absorptive capacity and aeration levels nat_re of the water (water type)> a black water type with its • *' *»’ , * characteristic high* level .of organi,c matter will accele- and '* rate• . the rate of sedimentation/T,— thereby- hasten the rate of/ * accummulation of the adsorbed and absorbed hydrocarbons. Then more importantly is the speed of the water. A fast flowing water would not to some-'extent support fast accummulat_i on of petroleunr hydrocarbc on*s within the immediate surroundings of -the point of-introduction. For a point to be able to accummuiate a reasonable * level of petroleum hydrocarbon, it has to combine factors such as fine sediment particles (clay and mud) known for high absorptive capacity, high level of suspe’nded organic matter, slow7 moving water body, and the level of introduction of petroleum hydrocarbon into the yater system, which has to keep pace with the rate of degradation because if the latter outpace-the rate of introduction, there would not be anything left to. accummuiate. UNIVERSITY OF IBADAN LIBRARY 543 'The resul-ts'in Table ' 73 • show some.. po.int s t.o have very' high concentration factor - Warri'-river above . Keremo (865)- - 5520, Port Harcourt Harbour (233a) - 7310, Bakana (807) - 1077.5. Other points, with relatively high concentration factors are Lever Brothers' discharge (845) - 435.'7. 'Okobaba Sawmill (847) - 294.8, Ifarri river field. (053) f- 814.1, Chanomi creek below mouth .of Oyeye creek (351) - 815 and Lower Orashi river (819') - 185.7. All these -points are located'in areas where the introduction of - petroleum hydrocarbons is more 'or less on a regular basis either through operational source, intentional or accidental discharges. They' also have mud sediment which can'effectively retain organic compound including petroleum hydrocarbon and the sediment matrix is not well aerated to allow for oxidative degradation of the petroleum hydrocarbons. • .Points like North of NNPC Facility on Lagos Lagoon (087) have a concentration factor of 34.6. Benin City on Ikpoba river (311) - 79.6, Oguta -Pontoon Crossing (016) - 60.6, Umuochi (020) - 55 and Azumini river at ' UNIVERSITY OF IBADAN LIBRARY T A B L E 7 3 : C O M P A R I S O N O F T H E A L I P H A T I C H Y D R O C A R B O N S ( B Y G C ) I N W A T E R A N D . S E D I M E N T S A M P L E ' S F R O M S A M E S A M P L I N G S I T E S a m p l e S a m p l e , W a t e r S e d i m e n t C o n c e n t r a t i o n • C o d e L i t h o l o g y m g / 1 f i g / g F a c t o r 1 L A G O S L A G O O N • 0 8 6 . M u d ' 0 . 1 4 1 1 0 . 5 7 0 7 5 . 0 ' 0 8 7 ’ F i n e s a n d 0 . 2 7 2 9 . 4 1 0 3 4 . 6 8 4 5 \ M u d 0 . 2 0 9 9 1 . 0 7 0 4 3 5 . 7 8 4 7 M u d - _ 0 - 1 3 0 3 8 . 3 2 0 2 9 4 . 8 • * • * B E N I N R I V E R S Y S T E M 1 3 4 M u d 0 . 9 0 4 4 . 3 2 0 - . 4 . 8 3 1 1 C o a r s e s a n d O’ . 0 2 5 . 1 . 9 9 0 • • 7 9 . 6 \ E S C R A V O S R I V E R S Y S T E M \ • 0 5 5 M u d 0 . 1 5 1 1 . 7 6 0 1 1 ^ 7 8 3 3 M u d 0 . 2 6 5 2 . 8 0 0 . 1 0 . 6 F O R C A D O S - W A R R I R I V E R S Y S T E M 0 5 3 M u d 0 . 0 3 4 2 7 . 6 8 0 * 8 1 4 . T > 1 . M u d 0 . 0 0 2 1 . 6 3 0 8 1 5 . 0 8 6 3 M u d 0 . 0 0 1 5 . 5 2 0 5 5 2 0 . 0 UNIVERSITY OF IBADAN LIBRARY V . ...54 5 T A B L E 7 3 ( c o n t d . ) S a m p l e S a m p l e W a t e r S e d i m e n t C o n c e n t r a t i o n C o d e L i t h o l o g y • m g / l H - g / g F a c t o r •* O R A S H I • R I V E R S Y S T E M 0 1 6 F i n e 0 . 0 6 4 ■ 3 . 8 8 0 ' 6 0 . 6 0 3 5 ' . M u d 0 . 0 6 0 0 . 5 8 0 9 . 7 8 1 9 M u d ’ 0 . 0 0 7 1 . 3 0 0 ‘ . 1 8 5 •. 7 B O N N Y - N E W C A L A B A R R I V E R . S Y S T E M 0 1 8 - Mud 0 . 0 3 9 0 . 5 0 1 2 . 8 0 2 0 C o a r s e s a n d 0 . 0 2 2 1 . 2 1 5 5 . 0 • 2 33 a • / M u d "— * 0.001 7 . 3 1 ' 7 3 1 0 . 0 8 0 7 M u d 0 . 0 1 6 . 1 7 . 2 4 1 0 7 7 . 5 8 0 8 F i n e s a n d 0 . 0 4 1 2 . 0 0 4 8 . 8 8 1 0 S a n d / p e b b l e s 0 . 5 4 3 0 . 8 8 1 . 6 • I M O R I V E R S Y S T E M ' 8 1 4 F i n e s a n d 0 . 0 4 6 1 . 3 5 0 2 9 . 3 i UNIVERSITY OF IBADAN LIBRARY 546 Aba - 29.3. These are points having sand particles ' l* ' ’ - • vita poor absorptive capacity and where oxidative degradation is also £p likely process to degrade the X - •petroleum hydrocarbons. ■ . 4.14 COMPARISON 'OF -LEVELS OF PETROLEUM HYDROCARBONS IN SEDIMENTS OF NIGERIAN COASTAL WATERS WITH SIMILAR RESULTS FROM OTHER COUNTRIES In order to assess the quality of the Nigerian ■ coastal environment in terms of petroleum .hydrocarbons pollution as a result'of the activities of the various industries e.g. oil companies, the 'results, reported in this study .must be compared with results reported for similar work in other parts of the world. The results of this study are presented alongside other results from other countries in Table 74 below. The results are collections of data from different systems - harbours, bays, lakes, islands and rivers. ^^The results from Lagos Laggon•sediments are .comparable to those of highly contaminated sediments. That is", total hydrocarbons in the sediments hear the densely UNIVERSITY OF IBADAN IBRARY 547 populated lake shore of Lake Zug in Switzerland have been estimated to be 240-290pg/g In Lake Washington, U.S.A., Wakeham and Carpenter (265 have ■ . reported that most surface sediments contain an average of about 1400pg/g total aliphatic hydrocarbons. Thus the Niger Delta area is not seriously contaminated. Apart from some scattered points that are located within the oil production areas or next to some urban settlements, most of the points recorded values that are comparable to the unpolluted sediments of Rothernemere (UK) - 37pg/g reported by Thompson and Eglinton (1978) , Barrier Islands (Gulf of Mexico) had 0.10-2.8pg/g (Palacas et al, 1976) and Chichinjima Island, Japan, 54pg/g . The Okpari river (a case study) was polluted in 1984 as a result of an oil spill from a ruptured pipe but the river quickly recovered in 1985 (see Table 62) with the average concentration of total hydrocarbons dropping from 101.66 pg/g (1984) to 20.62 pg/g (1985). UNIVERSITY OF IBADAN LIBRARY • ■ 548 Therefore, the high contents of hydrocarbons for the sediments from the marine water (represented by Lagos Lagoon) can be attributed to our daily urban - industrial activities, including industrial effluents, ship and boat traffic, sewage disposal and probably oil seeps (underground tanks). The Lagoon is well known for its poor circulation system and low levels of freshwater input which prevent effective flushing. Consequently, pollutants e.g. petroleum hydrocarbons, accummulate in the water column and sediments. The low contents of hydrocarbons recorded for the sediments from Niger Delta (fresh water) may be explained by factors such as proximity of some of the points from oil activity areas, lithology of the samples, tidal influence and the water circulation systems. Most of the river systems in the Niger Delta are well served with good circulation system and reasonable level of freshwater input. The rivers are also fast flowing in most of the points involved. UNIVERSITY OF IBADAN LIBRARY 549 TABLE 74: COMPARISON OF PETROLEUM HYDROCARBON (ALIPHATIC FRACTION) ' LEVELS IN’ SEDIMENTS OF NIGERIA COASTAL WATER WITH SIMILAR RESULTS FROM OTHER COUNTRIES • Station. . Aliphatic tyg/g) • Reference Comment • Wild Harbour 250-1,600 Blumer and Sass (1972) ■ Sub’tidal, oil spil polluti Buzzard. s Bay, Mas* sachusetts, USA .50-70 Blumer and Sass (1972) Polluted• River Blyth (U.K) ' 3,320 Cooper et al,(1974) Intertidal polluted •Lake Zug, Switzer land ,240-900 Giger et al.(1974‘) * , * Polluted Lake Washington, 'USA 1,600 Wakemar and Carpenter (1976) , Subtidal polluted Barrier Islands (Gulf of Mexico) ’0.10-2.S Palacas et al.(1976) Unpolluted. Buzzards Bay USA . ' 110 Farrington at ai.(1977) Subtidal polluted Wide Wall Bay 0.125-0.486 Mavron Kas (1978) Unpolluted / South Forties ' 3.84- 8.48 Mavron Kas (.1978) . Unpolluted Crangcmoult 147-483 fjavron Kas (1978) . Intertidal polluted Rothernemere^ U.K 37 Thompson and F.glintdn (1978) Unpolluted Chedabucpo, Bay 5-2,092 Keizer et al.(1978) Subtidal polluted . l • Narragansett Bay 2.3-5,410 Van Vleet and Quinn (1978) Subtidal polluted Long Cove, Maine 3-1,647 Mayo et al,(1978) Oil leakage Bermuda Seamount ' 0.6-1.5 Sleeter et al.(1979) Subtidal unpolluted New York Bight,(USA) 308 Koons and Thomas (1979) Subtidal, oil spill New York Bight, (USA) 35-2900 Wakeham and Farrington (1980) Sewagp Sludge and dredge' V UNIVERSITY OF IBADAN LIBRARY \ 5 50 TABLE 74 Cont. Station- Aliphatic(ug/g) Reference Comment • Kinneil - ’ 250-1,-000 Hartley (1980, 1981) Spoil dumping subtidal polluted •Tana river, Tokyo, Japan • 266-1,194 Matsurnoto (1983) Polluted Chichi-Jima Island, Japan 54 Matsurnoto (1983) Unpolluted Lagos and Lekki: Lagoon, Nigeria • ‘0.2-2703.4 This Study (1984-85) Polluted ' Niger Delta, Nigeria 0.02-69.52: • This Study '(1984-1985) Intertidal unpolluted to slightly polluted Okpari river, Nigeria 10.42-241.23 ' This Stiady (1984) • Oil sjJiJJ., polluted. Okpari river, Nigeria 0.02-63.95 This Study (1985). Oil spill slightly polluted \ \ / / UNIVERSITY OF IBADAN LIBRARY 5 51 4.15 . CONCLUSION ' ' . The results of this study indicated that petro- 1-eum hydrocarbons are present both in the water column and the underlying sediments of Nigerian river systems to varying degrees. • . The' levels .of petroleum hydrocarbon in both water and sediments varying between samples to reflect the site activity and-the nature of the river system. Samples from oil activity areas recorded’higher levels of petroleum hydrocarbons - 55.41--2766. 27 (221.'05) pgg-̂ than those from more remote‘-areas ND - 64.13 (40.07).pgg Apart from Oil installations, boat tpaffic•also showed its impact as high concentration of petroleum hydro- ,1. - ” . carbons in some locations can best be explained with reference to the volume of boat traffic along such routes. Industrial effluents, urban settlements - waste oil from-petrol stations and mechanic garages are other sources identified especially around Lagos ""^Lagoon. • Seasonal variation was indicated in the results of the. petroleum hydrocarbons in water samples in UNIVERSITY OF IBADAN LIBRARY 552 favour of the wet period over the dry period. This say oe due to river and urban run-off with their loa_Js .°f pollutants ■ including petroleum hydrocarbons. - •Mixing which may occur as a result of turbulent move­ ment in the water body also help to re-suspend the ’’ v », ^ already adsorbed dr assimilated petroleum hydrocarbon from the sediments, this would invariably boost the levels of petroleum hydrocarbons in the-water column during the wet season. On the other hand, the variation in petroleum hydrocarbons levels in sediments did not follow a clear course like those of the water because quite a lot of factors that are interwoven are responsible for the control of the levels of petroleum hydrocarbons available in sediments. • Comparing the different river systems, Lagos Lagoon showed higher level of contamination ND - 2766.27 (52.19) pgg ̂than the delta river systems 0.05.- 74.05-(9.07) • pgg-'*'. It implies that there are other sources of- petroleum hydrocarbons into the coastal water, especially around Lagos Lagoon that also needs dese rve UNIVERSITY OF IBADAN LIBRARY 553 attention as the one being focus on the Delta area. Some sources such as the industrial effluents, and the surreptitious release of oil from the numerous petrel service stations, mechanic workshops etc. have not been given adequate attention. - Lagos Lagoon with, its poor circulation is under heavy stress from these sources. Hence, the high level of contamination from petroleum hydrocarbon found around the Lagoon. • Hydrocarbon pollution of the Niger Delta while not yet as calamitous .as in. the western .Mediterranean Mediterranean^76) £s nevertheless significant. The area contains oil terminals, two oil refineries (the f. 9 third is underway),, petrochemical indus-tries, and busy ports. Lagos also has very bu.sy ports and many industries. Barring an/ major disaster, severe problems from oil pollution can be expected to arise in the near- future in Nigerian coastal waters unless effective measures are taken to reduce the rate at which oil is spilled during normal operations. If the statistics UNIVERSITY OF IBADAN LIBRARY .5 54 of oil spills given earlier 'in Tables ‘14- and 15 are ‘anything to go by, then we need to re-examine the industrial practice, of the various oil companies and make it mandatory for them to update their production technology. .Waste-water discharges also need strict control and monitoring. In attempts to assess the actual effect of petro­ leum hydrocarbon discharge on a particular ecosystem, it is essential that we understand the range of natural fluctuation-that can bo expected within the ecosystem, that is, a measure of the background., level against, which we- are going to attempt .to measure the pollution-linked effect. There must be a sufficiently . critical scientific base for responsible environmental protection policy. It is essential that we use what reliable data and experience we have to ensure the maintenance' of the best practical environmental policy. The results of this study have shown that, infrared -"spectrophotometric method and the gas chromatographic method are well suited for the monitoring of petroleum hydrocarbons! in our environment, there is a positive UNIVERSITY OF IBADAN LIBRARY 55b . correlation between the two values (i = 0.668) and the two components used as indicators -.water and sediments have proved -quite adequate'. They can ;be. used to complement the results of a third component - particulate-feeding biota, notably shellfish (e.g. mussels) to obtain a complete picture of the petroleum hydrocarbons pollution levels in our environment. In conclusion, since there has not been any previous baseline study on the present distribution of petroleum hydrocarbons in water and sediments of the Nigerian co.astal waters,- the results ■ obtained in this study would therefore, represent -baseline levels for future work on petroleum hydrocarbons in- water and sediments in . Nigerian coastal* water's. \ 4.16 SUGGESTIONS FOR FUTURE STUDY The results of this work will in no doubt serve * , • as a springboard for those who are going to wor.k in ^this area of petroleum hydrocarbon pollution study. The results can be used as a guide for the selection of ’hot spots’ where more attention, would need to be. focussed. UNIVERSITY OF IBADAN LIBRARY 556 Aromatics determination, by .glass capillary Gas Chromatography (GC) 2" and mass spectrometry (MS)' for detail, study Of individual aromatic hydrocarbon ♦ f * especially the polynuclear aromatic hydrocarbons is very necessary because of their importance. 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