Health risk assessment of heavy metals in soils within the vicinity of a metal recycling factory in Southwestern Nigeria

Abstract

Industrial emissions from scrap metal recycling plants have been implicated as a major source of heavy metal (HM) contamination to soil and threatens the wellbeing of humans, and our terrestrial environment. This study evaluated the seasonal variations of surface soil concentration of Al, Cd, Cu, Mn, Pb and Zn within the vicinity of a metal recycling factory in Ile-Ife, Nigeria. Sixty-six surface soil samples were systematically collected at 0-15 cm depth across three consecutive months during dry and rainy seasons from the factory premises vicinity. Samples determination of heavy metals contamination were conducted using Atomic Absorption Spectroscopy. Public health risks were evaluated using Geo-accumulation Indices (Igeo), Average daily intake, health quotient (HQ) and health index (HI) standards not exceeding average shale limits and between acceptable range 1×10-4 and 1×10-6. Total concentration (mg/kg) of heavy metals in soil samples ranged from 0.50 Al to 2,219.10 μg/g Cu during wet season, while the range was from 0.59 Al to 3,019.10μg/g Cu in dry season. Results of non-carcinogenic risks of HMs for HQ (0.038) and HI (0.06) values were generally lower than one (<1) indicating no health risk. However, the HI values for children were higher than those of the adults. An exception to this is the high HI value for Cu at 1.23 and 1.11 for children and adult, respectively. The study concluded that the study area soil was heavily polluted with Cu and Cd, and the HI values for children indicated that children could suffer higher potential health risk than adults.