Assessment of Potentially Toxic Metals in Selected Local and Foreign Rice Brands from Southwestern Nigeria: Implications for Human Health

This study evaluated the presence of potentially toxic metals (PTMs) in different local and foreign rice brands from southwestern Nigeria. Eight brands were purchased in four states: Oyo, Osun, Ogun, and Lagos. A total of sixty-four rice samples were analyzed for PTMs metals (Cd, Pb, Cr, Ni, Cu, Fe, Mn, and Zn) using an atomic absorption spectrophotometer. The data collected were analyzed for descriptive and inferential statistics. Health risk assessments were conducted to evaluate non-carcinogenic risks, including hazard quotient (HQ) and hazard index (HI), and cancer risk (CR). The results revealed high concentrations of Pb (7.13±5.40mg/kg) and Cd (8.71±3.81mg/kg) in the local brand and a high Cr (5.91±3.71mg/kg) in the foreign brand, which exceeded the WHO permissible limits of 0.2, 0.3, and 1.0mg/kg, respectively. The health risk assessment revealed that the HQ values exceeded the permissible limit of 1.0 for Pb, Cd, and Cr in most of the rice brands, indicating adverse health effects. The CR data revealed health concerns for Cd, Cr, and Ni, with values exceeding the limit of 1.0 × 10-4. This suggests a potential risk of cancer development associated with consuming the locally produced and imported rice in the states under study.