Assessment of Vapor Intrusion Risks in Chlorinated Solvent-Contaminated Subsurface Environments: Implications for Environmental Quality Standards in Urban Areas

In managing the urban subsurface environment contaminated by chlorinated solvents, various criteria, including environmental quality standards and human health risks, should be considered as the basis for decision-making. Vapor intrusion, particularly in urban environments, can serve as a major pathway for human exposure to soil or groundwater contamination, leading to indoor air pollution and posing potential health risks. In this study, the vapor intrusion risk posed by chlorinated solvents was assessed at levels meeting the environmental quality standards in South Korea. The results indicated that the vapor intrusion risks exceeded the acceptable risk criteria by approximately two to four orders of magnitude. Despite variations in site conditions, the health risk remained a significant concern. The case studies demonstrated that health risks exceeding the acceptable risk criteria can occur at contaminated sites that do not exceed environmental quality standards. They also highlighted that contaminated site management decisions can vary depending on the applied criteria. This study focused on vapor intrusion; additional pathways may further increase the risk. The risk criteria appear more stringent than environmental quality standards. It is necessary to revise the environmental quality standards for chlorinated solvent contamination, especially concerning urban subsurface pollution, or to apply site-specific criteria. This underscores the need for a cautious and conservative approach in managing urban contaminated sites and suggests that vapor intrusion risk assessment can serve as an effective tool in environmental risk management.