基于风险的农田镉污染综合管理实践与思考

Thinking and Practice of Integrated Management of Farmland Cadmium Pollution Risk

依托世行贷款湖南省农田污染综合管理项目,对湖南开展的大面积农田土壤修复治理项目的整体效果及实施过程进行了系统梳理,阐明了大面积镉污染农田修复治理中稻米镉达标率与土壤pH值及土壤有效态镉含量的关系。结果表明:调理土壤pH值至中性是提升稻米镉达标率的重要途径,且土壤pH值越低时调理效果越好;钝化土壤镉活性也是提升稻米镉达标率的重要途径,但在土壤有效态镉含量较低(<0.29 mg/kg)时存在报酬递减效应,而在土壤有效态镉含量较高(>0.29 mg/kg)时,通过钝化土壤镉活性提升稻米镉含量达标率的效果更理想。最后,从以人为本的先进管理理念、基于污染风险的项目管理手段、对症查因对靶施策的精准治理方案、以大户为主体的实施方式、多层次技术指导和第三方交叉监督过程等方面系统梳理了项目实施的管理经验,可为湖南乃至南方大面积镉污染耕地的安全利用提供经验参考。

Based on the Hunan farmland pollution integrated management project funded by the World Bank,this paper has systematically made classification and summarization concerning the overall effect and implementation process of the large-scale soil remediation and management project.Furthermore,the relationship between the cadmium compliance rate of rice and soil pH and soil available cadmium content was clarified.The results showed that adjusting soil pH value to neutrality was an important way to improve the cadmium compliance rate of rice,and the conditioning effect was better when the baseline of soil pH was lower.Passivation of soilcadmium activity was also an important way to improve the cadmium compliance rate of rice,but there was a diminishing return effectwhen the soil available cadmium content was low (<0.29 mg/kg);when soil available cadmium content was high (>0.29 mg/kg),deactivatingthe soil cadmium activity was more ideal to improve the cadmium compliance rate of rice.This paper has also systematically combed the projectimplementation management experience focusing on the people-oriented advanced management concept,the project management skills based on pollution risk control,the precision remediation plan towards targets and problems,the implementing scheme with large agriculturalentities as the main object,multi-level technical guidance and the third-party cross-supervision process.The results could provide experiencereference for the safe use of large-scale cadmium contaminated paddy fields in Hunan Province and even the south area of China.