The presence of persistent organic pollutants (POPs) and heavy metals in farmed fish raises a global concern. There is the need for comprehensive monitoring of these pollutants, which present risk to the aquatic ecosystem as well as to humans through the dietary consumption of farmed fish. The levels of selected indicators: polychlorinated biphenyls, organochlorine pesticides and heavy metals in water, sediment, cage tilapia and fish feed samples from four cage aquaculture farms on the Volta Basin were investigated. The organochlorine pesticides (OCPs) were quantified using the Gas Chromatography equipped with Electron Capture Detector (GC-ECD); the polychlorinated biphenyls (PCBs) with GC/MS and the heavy metals, the Atomic Absorption Spectrometer (AAS). Hexane was used as a solvent for the water extraction for pesticides. At the same time, sediment, cage tilapia and fish feed were sonicated in an ultrasonic bath using an acetone/hexane (2:1v/v) solvent mixture. After the clean-up, the eluates were condensed in a rotary vacuum evaporator and collected in 2 ml ethyl acetate vial for GC analysis. A mixture of HNO3/HCl/H2O2 was used to digest fish, fish feed, sediment, and water samples for heavy metals. The concentrations of OCPs in water range, <LOD – 0.799 μg/l (fish farm A), <LOD – 0.520 μg/l (fish farm B), <LOD – 1.173 μg/l (fish farm C), <LOD – 0.280 μg/l (fish farm D) and <LOD – 0.037μg/l (Control). The predominant OCPs in water were methoxychlor, o,p'-DDD, α-endosulfan, methoxychlor, and δ-HCH in fish farms A, B, C, D, and control, respectively. The sediment OCPs levels range; <LOD – 8.253 μg/kg (fish farm A), ND – 6.00 μg/kg (fish farm B), ND – 2.362 μg/kg (fish farm C), ND – 13.861 μg/kg (fish farm D) and ND – 0.503μg/kg (control). -HCH, o,p'-DDD, α—endosulfan, o,p'-DDD and heptachlor were the predominantly detected OCPs in sediment sampled from fish farms A, B, C, D and control respectively. For the fish feed, the levels of the OCPs range ND – 2.21 μg/kg, ND – 4.02 μg/kg, ND- 7.87 μg/kg in fish farms A, B and D, respectively. Similarly, for the fish, the ranges were; ND – 2.310 μg/kg (fish farm A), <LOD – 4.260 μg/kg (fish farm B), <LOD – 6.109 μg/kg (fish farm D) and ND – 0.878 μg/kg (control). The highest concentration of 6.109 μg/kg was encountered for -HCH in the tilapia for fish farm D, whiles p,p'-DDE recorded the lowest in farm A. PCBs in water recorded a range of ND – 0.508 ng/l in fish farm A, ND – 0.528 ng/l in farm B, ND – 0.815 ng/l in farm C, ND – 0.594 ng/l in fish farm D and ND – 0.173 ng/l in control. In the sediment, the mean ranges of the PCBs were ND – 0.492 ng/g, ND – 0.475 ng/g, ND – 0.394 ng/g, ND – 3.328 ng/g and ND – 0.113ng/g in fish farms A, B, C, D and control respectively. For the heavy metals, Pb, Zn, Fe, Mn, Ni and Cr were detected in the water, sediment, fish feed and fish samples. The concentrations of OCPs, PCBs, and heavy metals in water, sediment, fish feed and fish were below the EU/WHO/USEPA MRL except for heptachlor in water from fish farms A, B, D, and endrin in the fish farm C. Pb in water and Mn in fish reported levels above the MRL. The study revealed that the pesticides in the sediment were from anthropogenic sources such as agricultural, industrial and municipal waste. Evaluating the ecotoxicological risk of the pesticides in the surface sediment using the sediment quality guidelines, it was evident that only ΣHCH could pose a health risk to the benthic organisms. It was also observed that the heavy metals detected in the sediment originated from both anthropogenic and lithogenic sources. There was a low potential ecological risk of the heavy metals to the organisms in the sediment during the period of observation. There was no health health risk associated with the consumption of caged tilapia, except tilapia from farms B and D contaminated with endrin, Cr, Ni, and As that could pose cancer risk to consumers. Further Laboratory-based research should be conducted on other contaminants and a detailed potential health risk assessment estimated for the sustainability of the aquaculture industry.

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