Status of metal accumulation in farmland soils across China: From distribution to risk assessment

Increasing metal pollution has drawn broad public attention in China due to severe environmental quality deterioration. However, so far, there has been no study to survey metal accumulation in Chinese farmland soil at the national scale. In this study, we determined 11 metals in farmland soils across the Mainland China. Our results indicated the concentrations of Pb, Cd, Zn, and Cu (10.1–184.2, 0.082–1.31, 20.2–321.9, 8.2–515.9 mg/kg, respectively) were elevated above their reference values. Moreover, these metals followed a similar geochemical distribution pattern. The accumulation of Pb, Cd, Zn, and Cu in soils may be associated with human activities for soil fertility. Cadmium had the highest pollution index (PI) of 5.28, and the average hazard quotients (HQs) for all the metals were below 1. Hence, except for Cd, the metals in Chinese arable soils are comparatively safe. Results from this study may provide valuable information for agricultural soil management in China.

► The first study on metal accumulation in Chinese farmland soil at the national scale.
► Provide valuable information for the soil assessment and management in China.
► Metals from anthropogenesis followed a similar geochemical distribution pattern.
► Agricultural practices contributed to the accumulation of Pb, Cd, Zn, Cu and Sb.
► Of all the metals, the risk of Cd was of most priority in Chinese arable soils.