Organochlorine Pesticide Residues in Fish Samples from Lagos Lagoon, Nigeria

The organochlorine pesticide (OCPs) residues were measured in three species of fish Tilapia zilli (Red belly Tilapia), Ethmalosa fimbriata (Bonga Shad) and Chrysichthys nigrodigitatus (Catfish). These fish species are a significant part of the diet of residents of Lagos Nigeria. The organochlorine pesticides analyzed include DDT(pp'1,1,1-trichloro-2,2-bis-(4-chlorophenyl) ethane), DDD, DDE (pp 1,1-dichloro-2, 2-bis-(4-chlorophenyl) ethylene, HCH (gamma 1,2,3,4,5,6-hexachlorocylohexane, HCB (hexachlorobenzene),Dieldrin (1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a octahydro-1,4,5,8 dimethanonaphthalene) and transnonachlor. The analysis was done using Gas Chromatograph with Electron Capture Detector. The mean concentration of OCPs ranged from 0.01-8.92 ppm. The concentration of the OCPs (except for HCHs) in fish samples in this study were below the extraneous residue limit of 5 ppm, set by the codex alimentarious commission of FAO-WHO-1997. However, the concentrations were higher than those detected during previous studies of fish samples from Lake Victoria, Uganda in Africa. Also the levels were quite high when compared with the allowable Federal Environmental Protection Agency (FEPA), now Federal Ministry of Environment limit and can be harmful if the trend is not checked. The study also showed that concentration of OCPs were higher in adult, than in Juvenile of most of the fish and there was no correlation observed between fat content and total concentration of OCPs.