Evaluating the Influence of Food Trade on Human Exposure to Heavy Metals via Crops in China

Crops can accumulate heavy metals (HMs) from soil, leading to human exposure through dietary intake. However, the influence of interregional food trade on dietary HMs exposure remains underexplored. In this study, using data derived from existing literature, the occurrence and distribution patterns of six HMs, namely arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), and zinc (Zn), in soil and crops across China were investigated. Furthermore, the influence of food trade on human exposure to soil-derived HMs was assessed. The average total concentration of the six HMs in soil was 234.01 ± 29.54 mg/kg, while concentrations in rice and wheat were 16.06 ± 2.91 mg/kg and 22.48 ± 4.22 mg/kg, respectively. The hazard quotients (HQs) for As in rice exceeded 1 in the Central, Central Coast, South Coast, Southwest, and Northeast regions, indicating potential health risks. Interregional food trade significantly redistributed these risks. Through rice consumption, the Central and Northeast regions accounted for up to 36.78% and 45.08% of the daily intakes of As and Cd in other regions, respectively. Similarly, through wheat consumption, the Central and Southwest regions accounted for up to 51.33% and 25.97% of the daily intakes of As and Cd, respectively. This redistribution is largely attributed to the concentration of major crop production in the Central, Northeast, and Southwest regions. Overall, this study highlights the critical role of interregional food trade in modulating population health risks associated with contaminants, providing a more accurate and comprehensive assessment of dietary HMs exposure.