中国农田土壤重金属污染防治挑战与对策

我国农田土壤重金属污染格局多样,区域污染风险突出。发达国家对污染土壤的修复经验对我国具有借鉴意义。我国农田土壤重金属污染防治面临土壤重金属空间异质性强、土壤类型及农作物品种对重金属累积差异大、土壤酸化严重、土壤元素失衡、不科学的发展方式、土壤重金属累积趋势难以逆转、土壤—农作物重金属累积线性关系不显著,修复技术不完善、修复措施长期风险调控机制缺失等主要挑战。根据我国农田土壤污染防治现状及课题组工作基础,我们提出以预防为主、保护优先和风险管控为基本思路,建立土壤污染防治体系,通过"土壤环境质量调查、土壤污染源头管控、分类管理和土壤环境质量基准推导"等4个步骤推进农田土壤重金属污染防治工作。

Challenges and Countermeasures for Heavy Metal Pollution Control in Farmlands of China

The agricultural soil in China has been widely polluted by heavy metals and the regional contamination is serious. The experience on soil remediation in developed countries is significantly instructive for farmland protection in China. The heavy metal pollution of farmlands in China faces great challenges including spatial heterogeneity of heavy metal accumulation, various enrichment characteristics depending on soil types and crop, soil acidification, loss of soil trace elements, unreasonable development patterns, significant input of heavy metal into soil, poor correlation between the heavy metal concentration in soil and crop plants, immature remediation techniques, and lack of long-term risk control measures. Responses to these problems, we proposed a soil prevention and control system to promote the remediation of contaminated cropland in China, which mainly focused on pollution prevention, and take prior protection as well as risk control as basic course. Based on this system, the soil pollution prevention and control work can be implemented through systematically procedures including soil environment investigation, pollution source control, risk assessment and classification management, and the derivation of soil quality threshold.