土壤气监测在污染地块调查评估中的优势、局限及解决思路

Soil gas monitoring for site investigation and risk assessment:Advantages,challenges and solutions

目前,我国污染地块调查评估以土壤监测为主,辅以地下水监测。这套方法对于挥发性有机物(VOCs)的特殊性考虑不足,可能出现遗漏污染区域的可能性。与土壤监测相比,土壤气监测在VOCs污染地块调查评估中具有可捕捉VOCs污染区域的能力更强,能更准确反映VOCs的气态扩散迁移过程和呼吸暴露风险,以及长期监测成本较低等优势,故有必要将土壤气监测作为VOCs污染地块调查评估的常规工作内容。针对土壤气监测在国内推广应用中仍受到缺乏土壤气采样技术规范、分析检测标准方法、土壤气环境质量标准或风险筛选值及相应的数据分析方法等问题的局限,提出相应的解决思路以供参考。

Current contaminated site investigation and risk assessment in China rely on soil monitoring,supplemented by groundwater monitoring.However,this method neglects the specificity of volatile organic compounds(VOCs)thus might miss some contaminated zones.In contrast to soil monitoring,soil gas monitoring has the following three advantages:(1)more capable of capturing highly contaminated zones by VOCs,(2)more effective in reflecting gas-phase diffusive transport and human respiratory exposure risk,and(3)less expensive for long term monitoring.Therefore,soil gas monitoring should be part of normal site investigation and risk assessment for VOC-impacted sites.However,there are four challenges associated with the application of soil gas monitoring in China:(1)lack of technical guidelines for soil gas sampling,(2)lack of standard analytical methods for soil gas VOCs at contaminated sites,(3)lack of environmental quality standard or risk control screening values of soil gas and(4)lack of analytical methods of soil gas monitoring data.Solutions to overcome these challenges are provided in this paper.