Organochlorine pesticide residues in fish (Alestes baremoze and Synodontis bastiani) from Warri River, Nigeria: Levels and human exposure assessment

Abstract

Organochlorine pesticides are among the group of agrochemicals with the potential for bioaccumulation in fish posing great threat to human health through fish consumption. In view of this, organochlorine pesticide residues (OCPs) were analysed in the muscle tissue of two freshwater fish species; Alestes baremoze and Synodontis bastiani from selected stations along Warri River, Nigeria, with the aim of assessing the human health risk associated with consumption. The fish were collected from landing sites located at Ovwian and Okwagbe communities along the Warri River. These communities are agrarian catchment areas with intensive pesticide use. Pesticides were analysed using Gas Chromatography (GC) equipped with electron capture detector (GC-ECD), while human risk assessment was carried out using human intake models. Results for pesticide analysis revealed that the concentrations of mean pesticide residues ranged from 0 to 0.0017 mg/kg in A. baremoze and 0 to 0.0014 mg/kg in S. bastiani. γ-HCH was the most commonly detected compound in A. baremoze and it accounted for 47.1% of the total pesticide residues in the fish, while α-HCH was the most dominant pesticide in S. bastiani accounting for 28.4% of the total pesticide residues in the fish samples. S. bastiani was the more contaminated of the two fish species; however, concentrations were not significantly higher (p>0.05). Results of the human health risk assessment from consumption of contaminated fish (A. baremoze and S. bastiani) raise the concern of possible carcinogenic health risk from exposure to pesticides through consumption of fish species.

Keywords: Alestes baremoze, Fish, Human exposure implications, Organochlorine pesticides, Synodontis bastiani