scholarly works
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Item Environmental considerations, legal issues and other problems of cage culture(2009) Olaifa, F. E.Item Acute toxicity of ethanol extracts of cocoa bean shell on sarotherodon galilaeus juveniles(Medwell Journals, 2008) Olaifa, F. E.; Hamzat, R. A.; Oyetoyan, O. OAn acute toxicity test of ethanol extract of cocoa bean shell (CBS), a by-product of cocoa processing was conducted on 250 Sarotherodon gallilaeus juveniles for 96 h. There were 5 treatments and one control with each having 3 replicates. The treatments were prepared as 10,000, 7500, 4167, 2315, 1286 and 0 mg L-1 (control). The aim of the experiment was to study the toxic effects of Ethanol extract of CBS. While, the control experiment produced no mortalities and adverse histopathological responses, there were reactions to the presence of CBS extract in all the treatments which included restlessness and mortality. The lethal concentrations at which fifty percent of the test population died (LC 50) obtained using the logarithm method were 7943, 5012 and 6310 mg L-1 for replicates 1, 2 and 3, respectively while the probit method gave 5878, 4865, 6103 mg L-1 for replicates 1, 2 and 3, respectively. Histopathological examination of control fish showed no lesions on all tissues examined. However, marked changes were observed in the liver in form of degenerative hepatocytes, multifocal aggregation of haemosiderin laden macrophages; in the gills as shortening of gill filaments and in the brain as spongiosis of white cerebral matter of fish subjected to various concentrations of CBS extract. It was concluded that ethanol CBS extract possessed piscicidal properties on S. gallilaeus which could be useful in culling stunted and unwanted fish populations from ponds before stockingItem A study of the plankton and benthos of Ekole river in Bayelsa state, Nigeria(UNAAB, 2007) Olaifa, F. E.; Leilei, K. E.A study was undertaken to determine the plankton and benthos of Ekole River in Bayelsa State of Nigeria. Surface water and sediment samples were collected in the dry (December-January) and wet (June –July) seasons between 2003 and 2004 for plankton and benthic analyses. The water temperature ranged from 27-33°C, pH 6.30-7.5, total suspended solids (T.S.S) 110-282 mg/L, Chloride 15.40- 39.6 mg/l, dissolved oxygen 4.11-10.83 mg/l and conductivity 64.5-84.55ìS/cm. The total plankton count ranged between 267 x 10³ and 11830 X 10 ³ / L. Forty three and forty seven species of phytoplankton belonging to five families were identified in the dry and rainy seasons respectively. The mean zooplankton population ranged from 1954 x 10 / L in the dry to 3479 x 10 / L in the wet season while the benthic organisms ranged from 113 x 10 / L to 152 x 10 /L in the rainy and dry seasons respectively. Bacillariophyceae dominated the phytoplankton while the rotifers dominated the zooplankton species. Some biological indicators of pollution: larval forms of Chironomids ,Odonatans and Ephemenopterans were also identified in the riverItem Physicochemical characteristics of Cross River and costal areas of Cross River and Akwa Ibom States, Nigeria(2006) Olaifa, F. E.A study was carried out to determine the physico-chemical characteristics of the Cross River and coastal area of Cross River and Akwa Ibom state of Nigeria. Water samples were collected in dry (March and December) and wet (July and October) seasons during four cruises on parts of Cross River and Ibeno coastline of Akwa Ibom state between 1999 and 2002. Surface (0-15cm and bottom (2-13m) water were assessed at nine stations for for temperature, dissolved oxygen (D, O) hydrogen ion concentration (pH), total dissolved solids(TDS) total suspended solid (TSS), salinity, nitrite, nitrate, ammonium, phosphate, sulphate, silicate, calcium magnesium, sodium, chloride, and potassium. Spatial variations (p<0.05) were observed in the water quality parameters examined while temporal variations were generally not. Station 8(a marine station and site of major oil industry activity) was significantly different from all other stations (p<0.05) in all parameters considered. It was concluded that the water quality of the area should be monitored regularly to keep track of the water quality as all these areas were impacted by a major oil silage in 1999.Item Hydrocarbon and heavy metal pollution of water and sediments of Cross River and Akwa Ibom coastal waters, Nigeira(Baywood Publishing Company, 2005) Olaifa, F. E.A study was undertaken to determine the total hydrocarbon (THC) and heavy metal content of water (surface: 0-15 cm and bottom: 2-13m), sediments (intertidal and waterbed) in coastal area of Cross River and Akwa Ibom states of Nigeria affected by a major oil spill in 1998. Water and sediments samples were collected in the dry (March and December) and wet (July and October) seasons between 1999 and 2002. Significant spatial variation (p-<0.05) was observed for THC and heavy metals. THC (mg/ L) averaged 0.998 for surface and 0.827 for bottom water. All heavy metals of interest: chromium, copper, cadmium, lead, iron, manganese, zinc, and vanadium were present in samples and sediments contained significantly higher (0.05) THC and heavy metals than water. Concentrations of THC in water and sediments exceeded World Health Organization's limits by an average of 0.9979 and 0.8269mg/L in surface and bottom waters respectively.Item Assessment of Toxicological impact of light crude oil on clarias gariepus (Burechell, 1822) fingerlings(2005) Olaifa, F. E.Oil spillage is of critical concern in Nigeria because of the problems of pollution and associated disturbances. It is therefore necessary to study the effects of oil pollution on fish using clarias gariepinus, a widely cultured fish species in the tropics. A short-term (96-hours), statics bioassay was carried out to determine the toxicity of crude oil (qua ibeo light) on C. gariepinus fingerlings. The biossay involved five treatment viz:0, 25, 50, 75, and 100µL/L. The water and fish samples were analyzed for total hydrocarbon content (THC) and heavy metals at the end of the experiment. There were significant differences (p<0.05) among the five treatments. The LC50 ( concentration at which 50 percent of the test population died) was 1.58µL/L. Lead, iron, cadmium and chromium were not detected in the water contaminated with the crude oil sample.Item Water and sediment qualities of Ekole river, Bayelsa state, Nigeria(2004) Olaifa, F. E.; Leilei, K. E.A study was carried out to determine the physico-chemical characteristics and heavy metal contents of the water and sediment of Ekole river in Bayelsa state, Nigeria. Water and sediment samples were collected in the dry (december/ January) and wet (June/July) seasons during 2003 and 2004. Surface water up to 15cm depth and sediments were sampled at nine locations: 100, 200, 400, 500m upstream; 0, 100, 200, 300, 400m downstream of an oil flow station. The samples were anlyzed for total suspended solids (TSS), pH, chloride, dissolved oxygen, conductivity and heavy metals. These parameters were either measured in-situ using approriate meters or analysed in the laboratory using standard methods. The results obtained were compared with the baseline ecological data for 'Gbaran Extended Field'. upstream of the study of the area. World Health Organization and the Federal Environment Protection Agency's standards for water quality. The results showed increase TSS. pH and conductivity of the water over the baseline data. All heavy metals of interest: cadmium(Cd), lead (Pb), mangaese (Mn) zinc(Zn), nickel(Ni) copper, (Cu), iron (Fe) and chromium (Cr) were present in the water while Ni, Cd and Cr, absent in the baseline data were detected. Significant increases (p<0.05) were recorded for iron, zinc, copper and managese over baseline data. Higher concerntrations (p<0.05) of heavy metals were recorded in sediments than water and the dominant metal was iron. It was concluded that changes in water quality had occured in Ekole river near Obama flow station and the need to adhere to existing environmental laws and regular monitoring recommended.Item Presence of hydrocarbons and heavy metals in some fish species in the cross river, Nigeria.(2004) Olaifa, F. E.; Ayodele, I. A.The study was undertaken to determine the total hydrocarbon (THC) and heavy metal contents of fish (finfish and shelf fish) in the cross river, Nigeria. Fish samples were collected in the dry (March) and rainy (October) seasons between 2000-2002. The finfish species identified in the study were Synodontis clarias, Sarotherodon galilaeus, Heterotis niloticus, Scholbe mystus, ansorgil and the shelfish were macrobrachium vollenhovonii and tympanotnomus luscalus. Significant difference (P<0.05) existed between finfish andshellfish in both THC and heavy metals contents. The levels of THC in fish exceeded the World Health Organization's limit of 0.0001 ppm by an average of 3.2 and 15.57 mg/kg in fin and shelffish respectively. High concerntrations of vanadium and THC in fish samples were the main indicators of pollution from petroleum sourcesItem Heavy metal contamination of clarias gariepinus from a lake and fish farm in Ibadan, Nigeria(Ibadan Biomedical Communications Group, 2004) Olaifa, F. E.; Olaifa, A. K.; Adelaja, A. A.; Owolabi, A. G.Adult Clarias gariepinus (African Catfish) were purchased from Eleiyele Lake and Zartech fish farm in Ibadan. Water samples were also collected in February (dry season) and June (rainy season), 2002. Gill, bone, intestine, muscle and water samples were analyzed for five metals: manganese, copper, zinc, iron, and chromium by atomic absorption spectroscopy (AAS) in two separate experiments. In each case, two tissues were compared with the levels of the metals in water viz: Gill, bone, and water; intestine, muscle and water. Generally, lower concentrations of the metals were recorded in water than fish tissues. Higher concentrations of zinc than recommended by the Federal Environmental Protection Agency were recorded in the fish during the dry season. Iron was the dominant metal in the muscle while Chromium was the least. Significant differences (p<0.05) were recorded in copper and zinc concentrations in the muscle, intestine and water during the dry and rainy seasons .In gill, bones and water, significant differences (p<0.05) were only recorded for the two stations for copper during the rainy season and only zinc was significantly different (p<0.05) in the dry season. It was concluded that though the heavy metals of interest were present in measurable quantities there were still within safe limits for consumptionItem Lethal and sub-lethal effects of copper to the African catfish (Clarias gariepinus) juveniles(Ibadan Biomedical Communications Group, 2004) Olaifa, F. E.; Olaifa, A. K.; Onwude, T. E.Lethal and sub-lethal effects of copper on Clarias gariepinus were studied using a 96-hour static bioassay. Copper (as copper chloride, CuCl2 . H2O) was used to prepare the stock solution from which five standard concentrations 0.0, 1.8, 3.2, 5.6, and 10.0 mg/L were prepared (coded A – E). 15 juvenile C. gariepinus fish having a mean weight and length 5.8g and 18 cm respectively were used. The 96-hour LC50 estimated using the logarithm method were 0.6, 0.71 and 0.7 mg/l for replicates 1, 2 and 3 respectively with mean as 0.67mg/l. Haematological changes were generally not significant (P> 0.05). Copper concentrations in bone and muscle-tissues were also determined. The mean copper concentration in bone ranged from 1.86 (treatment A) to 17.04 ppm (Treatment E) and muscle 1.29 (treatment A) to 55.5 ppm (treatment E). There were significant differences (p<0.05) in mortality among treatments