Health Risk Potentials of Some Metals Via Consumption of Some Food Crops at Iruekpen, Southern Nigeria

Studies have shown that heavy metals may be retained in food crops at higher than the permissible levels, thus posing health risks to consumers. The aim of the study was to assess the heavy metal health risks of consumption of some food crops in Iruekpen, a typical rural area in Nigeria. Nine metals; As, Cd, Cr, Co, Cu, Pb, Hg, Ni and Zn were assayed in fifteen food crops, while Cr, Cu and Pb were analyzed in soil samples using the atomic absorption spectrophotometer. The food crops included; plantain, coconut, beans, groundnut, ginger, pepper, white yam, cocoyam, cassava, maize, rice (local and foreign), green vegetable, fluted pumpkin and bitter leaf. The samples were processed by standard methods, and analyzed using atomic absorption spectrophotometer. Daily intake of metal (DIM), target hazard quotient (THQ), hazard index (HI) and transfer factor (TF) were estimated to check for potential health risks. Heavy metals were detected in the crops in the order Zn>Pb>Cu>Cr>Ni. The oral reference dose (Rfd) for Cr (0.003 mg/kg) was exceeded in yam (0.009), foreign rice (0.006), local rice (0.012), bitter leaf (0.01), beans (0.004) and pepper (0.005), while the RfD of Pb (0.0036 mg/kg) was exceeded in foreign rice (0.008) and fluted pumpkin (0.037) only. The THQs for Cr and Pb were >1 in 6 and 2 of the food samples respectively. Hazard indices were >1 in 7 food samples. Only Cu and Pb were detected in the soil samples. Chromium and lead exceeded the health risk indices in seven of the fifteen food crops studied and thus pose health risks to consumers of the food crops.