贵州省白菜种植土壤镉风险管控标准研究

The objective of this study was to derive regional soil Cd criteria for cultivated land. Six representative soils were collected from Guizhou plateau and were spiked with Cd（NO3）2 in a pot experiment using Chinese cabbage. Two widely utilized extractants, 0.43 mol·L^-1 HNO3 and 0.01 mol·L^-1 CaCl2, were also included to evaluate the phytoavailability of Cd and were correlated to Cd concentrations in cabbage by either linear regression or multi-linear regression（log transformed）. Soil Cd risk screening values（RSVs）and risk intervention values（RIVs）were back calculated based on food quality standards. The results indicated that total Cd and available Cd could be used to establish a highly significant regression model or multiple regression model for the Cd content in the edible parts of Chinese cabbage. Within the pH range（5.5≤pH≤8.0）, the calculated soil Cd RSVs50（0.8~1.7 mg·kg^-1）and RIVs95（2.8~8.4 mg·kg^-1）were higher than the existing national standard（GB 15618—2018）. The 0.43 mol·L^-1 HNO3-Cd based soil Cd criteria increased with increasing soil pH. The 0.01 mol·L^-1 CaCl2-Cd based soil Cd criteria was independent of soil pH. RSVs95, RSVs50, and RIVs95 were 0.02, 0.078 mg·kg^-1, and 0.09 mg·kg^-1, respectively. Standard suitability assessment using field and literature data showed that the existing national soil Cd standard was rather conservative. The RSVs50 based on total Cd and two available Cd proposed in this study showed a high rate of correctness（>80%）. The present study confirmed that for better risk management of agricultural land, the establishment of regional soil environmental standards based on available concentration and specific crops is required.