Levels of persistent organochlorine and polychlorinated biphenyls in Nile tilapia (Oreochromis niloticus) from three cage aquaculture farms on the Volta Basin of Ghana: Implications for human health

Abstract

Increased agrochemical based agricultural activities along the Volta Basin and aquacultural practices from the cage farms have raised concerns about the potential ecological risk to the aquatic ecosystem. To assess this, caged tilapia samples were analysed for polychlorinated biphenyls (PCBs) and organochlorine pesticide (OCP).Fish samples in acetone/hexane (2:1v/v) solvent medium were sonicated on ultrasonic bath, shaken electronically, cleaned by solid-phase extraction and analysed by GC/ECD for OCPs and GC/MS for PCBs.The levels of OCPs reported in the fish ranged; ND – 2.310 µg/kg (fish farm A), <LOD – 4.260 µg/kg (fish farm B), <LOD – 6.109 µg/kg (fish farm C) and ND – 0.878µg/kg (control). The highest concentration of 6.109 µg/kg was encountered for δ-HCH in the muscles of Tilapia from fish farm C, whiles p,p'-DDE recorded the lowest in farm A. The levels of the OCPs detected in the cage tilapia were below the MRL proposed by the EU. Six PCBs congeners; PCB 18, PCB 28, PCB 52, PCB 101, PCB153 and PCB 180 were detected in the cage tilapia. The concentrations of the indicator congeners ranged from 0.288 ng/g to 0.931 ng/g dw, 0.042 ng/g to 1.321 ng/g dw, 0.260 ng/g to 10.657 ng/g, and ND-0.298ng/g dw in fish farm A, B, C and control respectively. The highest mean concentrations of PCB 153 (8.524 ± 1.5960ng/g) was found in farm Estimation of the EDIs and HQs for the pesticides do not present potential health risk to the consumers of the cage tilapia fish from the studied farms.