Bioconcentrations and health risk assessment of heavy metals in crops in the Naoli River Basin agricultural area, Sanjiang Plain, China

Ingesting crop grains contaminated with heavy metals is the most urgent problem related to food security and human health. Additionally, an overall analysis of heavy metal concentrations in different crop organs has guiding significance for ensuring food safety production. In this study, the concentrations of Cr, Ni, Cu, Zn, As, Cd, Hg, and Pb in soil, corn and soybean were determined in an agricultural area to assess the health risks associated with the ingestion of crop grains. Results showed the soil heavy metals were at a moderate pollution level, with an average pollution load index (\({\text{PLI}}\)) of 1.07. For heavy metals Cr, Ni, Cu, Zn, As, and Cd, the concentrations and bioconcentration factors in soybean grain were significantly higher than those in corn grain. For Hg and Pb, corn and soybean grains exhibited no difference in their concentrations and bioconcentration ability. Moreover, heavy metal concentrations in corn and soybean grains were at a very low polluted level and low polluted level, and the Nemerow comprehensive pollution index (\(P\)) values were 0.96 and 1.09, respectively. The hazard index (\({\text{HI}}\)) values for children caused by corn and soybean ingestion were all greater than 1, the target carcinogenic risk (TCR) values of Ni in corn and soybean for both children and adults were > 1 × 10⁻⁴, indicating the ingestion of heavy metals in crop grains posed a potential non-carcinogenic risk to children and a potential carcinogenic risk to both children and adults.