Derived regional soil-environmental quality criteria of metals based on Anhui soil-crop systems at the regulated level

Anhui province is a big agricultural province in China with regional heterogeneity, but there is still a lack of its regional soil-environmental quality standard for food safety and agricultural land protection. Herein, we collected 42 typical soil samples and 125 crop samples (roots, shoots and grains of wheat and rape) in the typical regions of northern, middle and southern Anhui province, and derived the regional criteria based on the current levels of eight metals (Cd, Cr, As, Pb, Hg, Cu, Zn, and Ni) as the basic items. Results showed that the metal concentrations in soil and crop samples varied with different Anhui regions and soil-crop systems. It was observed that there exists slight or moderate soil pollution (0.77-2.67), significantly higher concentrations (P < 0.05) in rape soils, generally higher concentrations (P > 0.05) in wheats, highest bioconcentration factor (BCF) in roots (0-9.570), and higher (P > 0.05) metal concentrations in the crops of southern and middle areas. The calculated regional soil-environmental quality criteria for Anhui province provided a new insight on developing regional soil-environmental quality criteria, which varied with different Anhui regions, and were >= 0.13-times lower than the screening values, except for Cd in the southern rape soil (0.351 mg/kg), but were generally higher for rape soils, except for Zn and As.