Evaluating the health risks associated with essential and non-essential metals in staple food crops sold in major markets in Nasarawa, Nigeria

The presence of hazardous metals in staple food crops poses a significant threat to human health. This study assessed the concentrations of some toxic and essential metals in black eye bean, soya bean, millet, sorghum, sesame seed, and locust bean obtained from major markets in Nasarawa, Nigeria, using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The results indicate that the mean metal concentrations in staple food crops exceeded WHO/FAO safety standards. Fe had the highest average concentrations (564 ± 52.0 to 1984 ± 124 mg/kg), which exceeded the WHO/FAO guideline of 425.5 mg/kg. Although Pb had the lowest mean concentration (3.80 ± 3.00 to 37.0 ± 14.0 mg/kg), it was still above the permissible limit of 0.20 mg/kg. The general concentration trend followed Fe > Zn > Mn > Ba > Se > Cr > Pb. Estimated daily intake values for most metals complied with USEPA reference thresholds, except for Cr in sesame seed for children, which exceeded safe limits. Hazard indices for black eye bean (1.30), millet (1.22), sorghum (1.29), sesame seed (2.60), and locust bean (1.72) were >1 in children. This indicates a possible health risk, except for the soya bean (0.83). Dermal contact posed a negligible risk, as all HI values were less than 1 for adults and children. The cancer risk value for Cr was above the acceptable range (1.0 × 10⁻⁶ to 1.0 × 10⁻⁴), indicating potential carcinogenic hazards associated with their consumption. Overall, the results raised concern, particularly for children, hence the urgent need for surveillance and awareness.