Soil contamination and plant accumulation characteristics of toxic metals and metalloid in farmland soil-food crop system in Qilihe, China.

Toxic metals and metalloids (TMMs) in soil can be accumulated in crops, which poses potential risks to human health. In this paper, 55 topsoil and 23 crop samples, collected in Qilihe, China, were selected to study the contamination, risk, and plant accumulation of TMMs in soil-crop system. TMM concentrations in soil samples were all below the permissible limits, but Hg and Cd exhibited the potential ecological risk due to their slight accumulation in soil. There was slight Hg pollution in 2 samples of Lanzhou lily (Lilium davidii), and 1 sample of radish (Raphanus sativus), Chinese cabbage (Brassica pekinensis), and welsh onions (Allium fistulosum) due to Hg’s strong bio-accumulation, but there was no risk to human health. The TMM accumulation in leaf crops was large, followed in tuber and seed crops. Available potassium, cation exchange capacity, soil organic matter, and available phosphate were the main factors associated with TMM accumulation in crops among the selected soil properties. This study shows the current contamination situation and the predominant influencing factors associated with the accumulation of TMMs in 24 crops, which provides the emphasis and direction of relative policies in land use and crop plantation.