Cadmium, chromium, nickel and lead content of fish and vegetables from selected dams in Osun State, Nigeria

Abstract

Potentially Toxic Elements (PTEs) in foods are a threat to global health. This study investigated concentrations of selected PTEs; cadmium, chromium, nickel and lead in fish and cultivated vegetables from and along the dams, respectively. Totally, 84 samples; 60 Tilapia (Oreochromis niloticus), 12 Okra (Abelmoschus esculentus) and 12 Bitter leaf (Vernonia amygdalina) obtained from six dams in Southwestern Nigeria were digested using aqua-regia. Elemental quantification with Flame Atomic Absorption Spectrophotometer and validation via recovery test (97.1–100%), linearity (R2 ≥ 0.997) and limit of detection (LOD) (0.01–0.18 mg kg-1) were done. The PTEs concentrations in the two vegetables did not maximum exceed the permissible levels, except for Pb. In fish samples, PTEs concentrations were > maximum permissible levels and ranged from 1.18 to 2.31, 3.15–3.92, 0.41–14.2 and 2.36–3.73 mg kg-1 for Cr, Ni, Cd and Pb respectively. Human health risk assessment revealed the Estimated Daily Intake (EDI) values for consumption of Tilapia by children for Pb and Cd were > Tolerable Daily Intake (TDI) while for adults, higher EDI values were for Pb. Conclusively, non-carcinogenic and carcinogenic assessment results reveal that consumption of tilapia, okra and bitter leaf from these dams is not safe.