Levels of Persistent Organochlorine Compounds in Nile Tilapia (Oreochromis niloticus) from Three Cage Aquaculture Farms on the Volta Basin of Ghana: Implications for Human Health

Increased agrochemical-based agricultural activities along the Volta basin and cage aquaculture 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 pesticides (OCP). Fish samples in acetone/hexane (2:1v/v) solvent medium were sonicated in an ultrasonic bath, shaken electronically, cleaned by solid-phase extraction, and analysed using GC/ECD for OCPs and GC/MS for PCBs. The levels of OCPs reported in the fish ranged; ND – 2.31 µg/kg (fish farm A), <LOD – 4.3 µg/kg (fish farm B), <LOD – 6.11 µg/kg (fish farm C) and ND – 0.88 µg/kg (control). The highest concentration of 6.11 µg/kg was encountered for δ-HCH in tilapia from fish farm C, while p,p’-DDE recorded the lowest in fish from Farm A. The levels of the OCPs detected in cage tilapia were below the maximum residue limits (MRL) proposed by the EU. Six PCBs congeners, i.e., PCB 18, PCB 28, PCB 52, PCB 101, PCB153 and PCB 180 were detected and concentrations ranged from 0.288 to 0.931 µg/kg dw, 0.042–1.321 µg/kg dw, 0.260-10.657 µg/kg dw, and ND − 0.298 µg/kg dw in fish Farms A, B, C and control, respectively. Risk assessment of POPs indicated that ∑PCBs in Farm C fish may pose health risk to consumers. Further analysis revealed that Farms B and C fish polluted with endrin may pose cancer risk to children consumers. Frequent monitoring of PCBs, OCPs and other contaminants is needed to mitigate the impacts on human health.