基于改进H?kanson法的水稻根系土壤重金属生态风险评价

H?kanson潜在生态风险评价法(简称"H?kanson法")是综合考虑污染物种类、丰度效应、沉积效应和敏感效应的沉积物生态风险评价方法将其应用在农田土壤生态风险评价中必须考虑土壤和沉积物环境中污染物种类、沉积效应和敏感效应的差异.该研究以安徽省某区域内水稻根系土壤为例,基于污染物种类改进H?kanson法(简称"修正法1")和基于污染物种类-生物吸收系数改进H?kanson法(简称"修正法2"),对水稻根系土壤重金属Pb、Hg、Cr、Cd和As进行生态风险评价.结果表明:修正法1和修正法2得到的Pb、Cr和As评价结果一致,但Hg和Cd的评价结果差异较大;基于稻米质量安全和保守原则,两种改进方法均能准确评价水稻根系土壤Pb、Cr和As生态风险,且修正法1对Cd生态风险评价较合理,修正法2对Hg污染风险评价较合理.研究显示,修正法1和修正法2均能合理地评价水稻根系土壤重金属尤其是Hg和Cd的生态风险.

Ecological Risk Assessment of Heavy Metals in Paddy Soil Based on Improved Håkanson Method

Håkanson potential ecological risk assessment method that comprehensively considers the types of pollutants, abundance effects, sedimentary effects and sensitive effects is commonly used for sediment risk assessment. It is necessary to take into account the differences of types of pollutants, sedimentary effects and sensitive effects between sediment and soil environment to apply the Håkanson method to assess the potential ecological risk of farmland soil. This study improved the method from the perspectives of pollutant types (improved method 1) and pollutant types-bioabsorption coefficients (improved method 2), and then applied them to assess the ecological risk of paddy soil. Here, a case study was conducted on paddy soil in an area in central Anhui Province. Two improved methods were used to evaluate the ecological risk of heavy metals (Pb, Hg, Cr, Cd and As) in the soil. Our findings indicate that the two improved methods have consistent evaluation results for Pb, Cr, and As, but the evaluation results for Hg and Cd are quite different. The two improved methods could be used to accurately evaluate the ecological risk of Pb, Cr, and As based on rice safety and conservative principles. In contrast, the improved method 1 is more suitable for evaluating the ecological risk of Cd, while the improved method 2 is more suitable for evaluating the ecological risk of Hg. In summary, both the improved method 1 and improved method 2 can reasonably evaluate the ecological risk of heavy metals in paddy soil, especially for Hg and Cd.