Evaluating the health risk of metals (Zn, Cr, Cd, Ni, Pb) in staple foods from Lagos and Ogun States, Southwestern Nigeria.

The study evaluated the health risk of metals in commonly consumed staple foods from Lagos and Ogun states, southwestern Nigeria. One hundred and thirty-three food samples were collected and analyzed for Zn, Cr, Cd, Ni, and Pb using atomic absorption spectrophotometric method. Data collected were analyzed for simple descriptive and inferential statistics using SPSS for Windows. The health risk of metals in staple foods was assessed for average daily dose (ADD), hazard quotient (HQ), hazard index (HI), and cancer risk (CR). Results showed the highest concentrations of Zn (18.99 ± 13.62 mg kg-1 ) and Ni (0.21 ± 0.10 mg kg-1 ) in beans, while the highest amount of Cr (2.04 ± 1.44 mg kg-1 ) was obtained in rice. Cd concentrations in staple foodstuffs ranged from < 0.01 to 0.30 mg kg-1 , while Pb was below the detection limit. The average levels of Zn in beans and maize were higher than the recommended dietary allowance (9.5 mg kg-1 ) of the Institute of Medicine. The mean concentrations of Cr and Cd (except for rice) in staple food samples were also higher than the permissible standards. The health risk data revealed HQ value greater than 1.0 for Cr in the food samples, indicating non-carcinogenic adverse health effects. The HI value greater than 1.0 in staple foods established cumulative adverse effects of metals. The carcinogenic evaluation of Cr (in all the food samples) and Ni (in beans) showed CR values greater than the acceptable limit of 1.0 × 10-4 , thereby demonstrating possible development of cancer through consumption of the staple foodstuffs.