Persistent Organochlorine Pesticide Residues in Water, Sediments and Fish Samples from Ogbese River
This study considered the levels of 15 organochlorine pesticide (OCPs) residues (a BHC, b BHC, U BHC, lindane, chlorothalonil, heptachlor, aldrin, heptachlor epoxide, endosulfan I, endosulfan II, endrin, dieldrin, p, p' DDD, p, p' DDT and endosulfan sulphate in water, sediments and fish species from Ogbese river in Ekiti State, Southwestern Nigeria. Samples were extracted and cleaned up on silica gel adsorbent. The OCPs concentrations were determined using Gas chromatograph (GC) equipped with Electron Capture Detector. The OCPs concentration in water and sediments ranged from below detection limit (BDL) BDL 13.6 ug/L and 0.52 450 ug/kg whilst the mean OCPs in the fish ranged from 2.64 66.0 ug/kg, respectively. The results indicated that all the analysed fish samples were contaminated with the studied pesticides. Endosulfan I was found to be above EU and FAO/WHO maximum residue limits (MRL) in Clarias gariepinus fish samples. The sediments and fish samples showed evidence of organochlorine pesticides enrichment and bioaccumulation. Chi square at a 0.05 showed there were significant differences in the levels of organochlorine pesticide residues in sediments and fish samples except a BHC.