Differences in enrichment and soil safety thresholds of five vegetables grown in Cd-polluted soil of Chengdu Plain, China.

Abstract

By examining the differences in cadmium (Cd) enrichment capacity among various vegetable species, this study assessed the health risks associated with consuming the edible parts of vegetables under different levels of soil Cd contamination in the Chengdu Plain. Based on these assessments, corresponding vegetable-soil Cd safety thresholds were established. Five commonly cultivated vegetable species-Lactuca sativa var. longifolia f. Lam. (Romaine lettuce), Lactuca sativa var. ramosa Hort. (cos lettuce), Brassica campestris L. ssp. chinensis Makino var. communis Tsen et Lee (pak choi), Raphanus sativus L. (radish), and Lactuca sativa var. angustata (lettuce)-were selected as research subjects to compare and analyze their Cd enrichment capacity across different soil Cd contamination levels (0.13, 0.20, 0.32, 0.73, and 1.02 mg kg^-1). Additionally, potential food safety concerns and health risks associated with Cd accumulation in vegetables were evaluated using the Hazard Quotient (HQi) criterion in human health risk assessment. The potential food safety and health risks associated with cadmium (Cd) contamination in vegetables were evaluated using the Hazard Quotient (HQi) criterion, and corresponding Cd safety thresholds for vegetable-growing soils were established. Health risk assessments based on dietary intake indicated that lettuce posed a higher risk than the other four vegetable species, and children were more vulnerable to Cd exposure than adults when consuming the same amount of vegetables. The Cd enrichment capacity of lettuce was significantly higher than that of Romaine lettuce, cos lettuce, pak choi, and radish (n = 5, P < 0.05). For the Chengdu Plain, the soil Cd safety thresholds were determined to be 0.32 mg kg^-1 for Romaine lettuce, cos lettuce, pak choi, and radish, and 0.20 mg kg^-1 for lettuce. These findings provide a scientific basis for ensuring vegetable quality and safety, refining Cd environmental quality standards for agricultural soils, and promoting the safe utilization of Cd-contaminated farmland.