Pesticide contamination and associated health risks in fish from Libga and Builpela reservoirs, Northern Ghana

Abstract Background Pesticide contamination in aquatic ecosystems due to intensive agriculture poses significant health risks to communities reliant on fish as a dietary staple. In northern Ghana, where intensive agriculture drives high pesticide use, residues from pesticide application persist in water bodies. Libga and Builpela reservoirs, important for local livelihoods and fish sources are exposed to agricultural effluents. Despite their importance, limited data exist on pesticide residues in fish from these reservoirs, nor have the associated health risks for surrounding communities been quantified. Persistent pesticides are of particular concern. This study assessed pesticide residues and human health risks in Clarias (C.) anguillaris (African catfish) and Oreochromis (O.) niloticus (Nile tilapia) fish from the Libga and Builpela reservoirs in northern Ghana, which receive substantial agricultural runoff. Methods Fish samples from both reservoirs were analysed for 42 pesticides using Liquid Chromatography-Tandem Mass Spectrometry (LC–MS/MS). Lifetime cancer risk, hazard quotient, and hazard ratio were computed to evaluate the health risks linked to fish consumption. Two species of fish, Clarias anguilaris and Oreochromis niloticus , were tested for pesticide contamination. Results Four pesticide residues were detected: pirimiphos-methyl, chlorpyriphos, p,p'-DDE, and p,p'-DDD. Clarias anguilaris exhibited higher organophosphate levels with pirimiphos-methyl: showing the highest concentration at 0.05 ± 0.02 mg/kg in Builpela and 0.04 ± 0.00 mg/kg in Libga reservoir. Oreochromis niloticus showed elevated organochlorines (p,p'-DDD and DDD: 0.03 ± 0.01 mg/kg). Organochlorines dominated the pesticide load (55–60%), with p,p'-DDE contributing 27.9% of the total. The hazard quotient and hazard ratio indicated little adverse health impacts. However, cumulative LCR values for p,p'-DDD and p,p'-DDE indicated potential lifetime cancer risks from chronic exposure. Conclusions In our study, though short-term consumption poses minimal non-carcinogenic risks, from consuming C. anguillaris and O. niloticus from these reservoirs, long-term intake of fish may elevate cancer risks due to persistent organochlorines. Regular monitoring, public health advisories, and stricter agricultural regulations are necessary to mitigate contamination and protect vulnerable communities in northern Ghana.