Organochlorine Pesticides and Polychlorinated Biphenyls in Sediment Impacted by Cage Aquaculture in the Volta Basin of Ghana.

Seventeen organochlorine pesticides (OCPs) and seven indicator polychlorinated biphenyls (PCBs) residues in 80 sediment samples from four cage aquaculture farms on the Volta Basin were determined to find out the extent of their contamination as well as their risk to biota in the aquatic ecosystem. The extracted residues of the OCPs and PCBs were analysed on a gas chromatograph equipped with an electron capture detector and mass spectrometer, respectively. Eleven (11) OCPs: methoxychlor, δ-HCH, o,p'-DDD, α-endosulphan, β-HCH, o,p-DDE, p,p-DDE, p,p'-DDT, β-endosulphan, endrin, and heptachlor and seven (7) PCBs: PCB 18, PCB 28, PCB 52, PCB 101, PCB 138, PCB 153, and PCB 180 were detected in the sediments from the farms. The OCPs level ranged < LOD - 33.0 µg/kg. δ-HCH (8.154 ± 0.414 µg/kg), α-endosulphan (6.000 ± 1.414 µg/kg), o,p'-DDD (2.010 ± 1.46 µg/kg), endrin (13.867 ± 8.716 µg/kg), and α-endosulphan (0.503 ± 0.398 µg/kg) were predominant with frequencies of detection 100%, 45%, 68%, 92%, and 25% in fish farms A, B, C, D and controls, respectively. PCBs concentrations ranged 0.042-5.320 ng/g wet weight. PCB 153 recorded the highest concentration of 3.328 ± 1.700 ng/g in farm D. PCB 18 and PCB 180 dominated the profiles in the sediment from all the farms. The ecotoxicological risk of the OCPs and PCBs in the surface sediment using the SQGs indicated that ∑HCH in the sediment from all the farms except that the controls may pose a health risk to the benthic organisms. Therefore, a comprehensive remedial intervention is required to arrest the situation.