Levels and human health risk assessment of persistent organics, metalloid and heavy metals in fish

Abstract

Concentrations of Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and heavy metals (Fe, Zn, Mn, Cu, Ni, Cd. V, Cr, Pb, Hg, As) were measured in fish (Clarias gariepinus) samples collected from selected stations (S1, S2 and S3) along the stretch of Ovia River, Southern Nigeria, to assess the potential risks to humans consuming fish from the river. Acenaphthylene (AcPY), 2,2',5-Trichlorobiphenyl (PCB 18) and iron (Fe) were the most dominant residues with mean concentrations ranging from 0.002 to 0.128, 0.001 to 0.003 and 175.97 to 255.52 mg/kg respectively. The most carcinogenic PAH, Benzo(a)pyrene (BaP) in S3, all the PCB congeners, cadmium (Cd), and lead (Pb) concentrations in the three stations were observed to be above EU recommended guideline values for food safety which calls for concern. Concentrations of dioxin‐like PCB congeners, 77, 105, 114 and the sum of carcinogenic PAHs also contributed to the toxic burden of these contaminants in fish. Estimation of the daily intake of PAHs, PCBs, and heavy metals showed values below the reference dose proposed by WHO for all the toxicants investigated, indicating that consumption of fish from Ovia River generally does not subject consumers to significant health risk. In contrast, the estimated cumulative THQ for the assessed heavy metals, however, indicate health risks from exposure to Heavy metals through fish consumption. Continuous surveillance and monitoring of the Ovia River are therefore imperative to mitigate further pollution.