制定我国污染场地土壤筛选值的建议

Proposal on Establishing Soil Screening Levels of Contaminated Sites in China

通过研究发达国家(地区)土壤重金属As、Cd、Cr6+、Pb、Hg和Cu筛选值制定的法律依据及其数值的差异,发现各国(地区)土壤筛选值均是依据其污染场地的法律法规确定,主要用于决策污染场地是否需要进一步的场地调查或风险评估。各国(地区)污染场地6种重金属土壤筛选值存在的差异既有政策层面(可接受风险水平),也有制定方法层面(暴露途径、暴露参数、场地水文地质参数、毒性数据、背景值等)的原因。建议我国尽快建立土壤筛选值的相关法律法规,并依据土地利用方式的敏感性确定不同层次的可接受风险水平;考虑具体场地的情况确定暴露参数和暴露途径,并落实各级筛选值的制定和实施办法。

Study on establishing risk-based soil screening levels of As, Cd, Cr6＋, Pb, Hg and Cu in the developed countries or regions showed that soil screening levels were mainly used to make decisions for further investigation or risk assessment of the contaminate sites. Reasons for the large differences among soil screening levels of the six countries or regions originated from both regulatory aspects including acceptable risk level and scientific aspects including exposure pathways, exposure assumption, toxicity parameters, soil and hydrographic parameters and background of heavy metals etc. Finally, it was suggested to establish regulatory framework for soil screening levels, to decide acceptable risk level according to the susceptivity of land use, to determine exposure parameters and ways by considering site specific situations, and to implement the establishing and applying methods or measures for soil screening levels.