Soil gas monitoring for site investigation and risk assessment: Advantages, challenges and solutions
MA Jie1,, State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing 102249, China
Abstract: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. Key words:contaminated site/ site investigation/ risk assessment/ soil gas/ volatile organic compounds/ soil/ groundwater.
图13种类型的土壤气监测井 Figure1.Three types of soil gas monitoring wells
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State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing 102249, China Received Date: 2020-11-17 Accepted Date: 2021-06-26 Available Online: 2021-09-15 Keywords:contaminated site/ site investigation/ risk assessment/ soil gas/ volatile organic compounds/ soil/ groundwater Abstract: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.