Comprehensive evaluation and safety zoning of cultivated land soil pollution risk in high geological background area
Cultivated land is the foundation of food production,it is an important measure to evaluate and classify heavy metal pollution in cultivated land soil to ensure the safety of agricultural products and human health.Taking the cultivated soil of Jinshan town,Nanchuan district,Chongqing as the research object,the single factor pollution index,Nemero comprehensive pollution index and potential ecological hazard index were used to evaluate and classify the heavy metal pollution risk of cultivated soil.The results showed that the average content of Cd in cultivated soil in the study area was 0.60 mg/kg,which exceeded the soil pollution risk screening value given in Soil Environmental Quality—Standard for the Control of Soil Pollution Risk of Agricultural Land(Trial)(GB 15618-2018)in 57.21％,and the other heavy metals did not exceed the standard.In the study area,the soil pollution was mainly light and mild,the ecological risk was mainly light and medium,the impact factor was Cd,and the pollution risk area was mainly distributed in the northeast and southwest of the study area.Geological background,landform and agricultural activities were the main factors affecting the distribution of heavy metal pollution in the soil of the study area.The areas of Class Ⅰ(safe area),Class Ⅱ(basic safe area),Class Ⅲ(low risk area),Class Ⅳ(medium risk area)and Class Ⅴ(high risk area)in the study area accounted for 11.2％,10.46％,31.51％,18.9％and 27.93％,respectively,and the medium-high risk was mainly distributed in the northeast and southwest of the study area.The over-standard rate of corn Cd in the study area was 26.31％,which was concentrated in the high risk area of cultivated land(Glass Ⅴ).It was suggested to carry out risk control in medium-high risk areas,strengthen the monitoring of agricultural inputs,take technical measures for the safe use of cultivated land,improve the soil environmental quality of polluted cultivated land,and improve the safety of agricultural products.
cultivated soilheavy metalspollution assessmentsecurity partitionrisk management and control
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