BASE-LINE LEVELS OF SELECTED ORGANOCHLORINE PESTICIDE-RESIDUES IN SURFACE WATERS IN IBADAN (NIGERIA) BY ELECTRON-CAPTURE GAS-CHROMATOGRAPHY

Organochlorine pesticide residues present in surface waters of Ibadan city, Western Nigeria were determined by electron capture gas chromatographic techniques. Some of the organics quantified include alpha,beta-BHC 0.001-0.3-mu-g/l, lindane (gamma-BHC) 0.007-0.3-mu-g/l, aldrin ND-0.04-mu-g/l, dieldrin 0.018-0.657-mu-g/l, endrin ND-0.019-mu-g/l, heptachlor 0.004-0.202-mu-g/l, endosulphan ND-0.43-mu-g/l, HCB ND-0.092-mu-g/l and total DDT ND-1.3-mu-g/l. These levels indicate relatively higher loads of organic contaminants in these water bodies compared with concentrations elsewhere. The results also establish that organochlorine pesticide residues are widely distributed in these surface waters even at sites quite remote from point sources