Assessment of Heavy Metals in Water and Fishes of Oyo Field and Ilaje Coastal Waters, Ondo State, Nigeria.

The study, aimed at assessing comparative concentration of heavy metals at the shoreline and about 70 km offshore, determined levels of heavy metals (Pb, Cd, As, Cr and Hg) in water and Tilapia bravemanus at the shoreline of Ilaje Local Government Area of Ondo State, Nigeria (SP1) using AAS technique. Same metals were assessed in water and Euthynnus alleteratus at Oyo Oil Field, about 70 km offshore of Ondo State (SP2). Trends of heavy metals in water and fish at SP1 were Hg > Cd > Cr > As > Pb and Hg > Cd > Cr > As > Pb respectively. While trends in water and fish at SP2 were Cr > Hg > Cd > As > Pb and Cr > Cd > As > Hg > Pb respectively. Bioaccumulation factor (BAF) in SP1 ranged from 217.43 to 1773. In SP2 it ranged from 31.34 to 331. Heavy metal contamination in water at SP1 was higher than at SP2. Similarly, heavy metal bioaccumulation in Tilapia brevimanus was higher than in Euthynnus alleteratus. Based on the outcome of the study, Tilapia brevimanus and Euthynnus alleteratus can be used as bio-indicators of heavy metal contamination in SP1 and SP2 respectively. [ABSTRACT FROM AUTHOR]