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| Risk threshold for soil cadmium, based on potato quality in a high geological background area |
| Received:August 24, 2020 |
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| KeyWord:potato;soil;cadmium;risk threshold;high geochemical background |
| Author Name | Affiliation | E-mail | | WANG Xu-lian | College of Agriculture, Guizhou University, Guiyang 550025, China | | | LIU Hong-yan | College of Agriculture, Guizhou University, Guiyang 550025, China
College of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China | hyliu@gzu.edu.cn | | ZHOU Xian-yong | College of Agriculture, Guizhou University, Guiyang 550025, China | | | LUO Kai | College of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China | | | YU En-jiang | College of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, China | | | RAN Xiao-zhui | College of Agriculture, Guizhou University, Guiyang 550025, China | |
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| Abstract: |
| To ensure the cleaner cultivation of potatoes in Karst region with a high geochemical background of cadmium(Cd)in southwest China, by using a total of 105 pairs of soil samples and corresponding potatoes were sourced from 5 counties of Guizhou Province as the test materials, taking the national food safety standards limits of pollutants for foods(GB 2762-2017, Cd<0.1 mg·kg-1)as the measure, we used the statistical regression model to derive the soil threshold values of total and available cadmium based on potato safety production. The results showed that the total Cd content of soil in the Hezhang County(HZ)and Weining County(WN)sampling areas exceeded the Chinese environmental quality standard for soil(GB 15618-2018), 92.3% of soil samples exceeded the screening value of agricultural land, and 77.4% of soil samples exceeded the control value and the soil was at the level of moderate to severe pollution. 80% soils in Changshun County(CS)and 50% in Ceheng County(CH)exceeded the screened value but not the regulated value, and the soil was at the level of no pollution in a geological high background area. The point position superstandard rate of potato Cd was 17.1%, and the superstandard multiple varied between 0.01 and 1.11, mainly distributed in WN. The correlation coefficients between potato Cd and soil Cd, as well as available Cd were 0.587 and 0.755, respectively, both showing strong positive correlation(P<0.01). The regression model simulated the risk thresholds of soil Cd based on the potato Cd limit standard were 4.30, 7.34 mg·kg-1, and 9.39 mg·kg-1 on soils with pH ≤ 6.5, 6.57.5, respectively; the corresponding thresholds of soil available Cd were 0.22, 0.02 mg·kg-1, and 0.01 mg·kg-1, respectively. The total Cd risk thresholds of contaminated soils simulated by HZ and WN in northwest Guizhou Province were 5.11(pH ≤ 6.5), 7.75(6.57.5)mg·kg-1, respectively. The risk threshold of soil Cd based on potato safety production is more than twice the risk control value of soil pollution in agricultural land, so the current soil Cd standard of agricultural land is applied strictly in the karst areas. |
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