The Evaluation of Risk for Exposure to Groundwater during Construction/Trench Work

摘要

During the cleanup of contaminated sites, it is often required that the health risk to construction/trench workers for exposure to impacted groundwater during intrusive work be evaluated. Regulatory agencies typically publish risk-based soil screening levels for direct contact to soil to facilitate risk evaluation, but rarely provide guidance or screening levels for exposure to groundwater during construction/trench work. While the risks from dermal contact with and incidental ingestion of groundwater can be readily evaluated using classic equations, the evaluation of risk from inhalation of vapor from groundwater is complicated by how airflow in the work zone affects the exposure concentration. Utilizing a groundwater volatilization factor that accounts for the airflow-induced dilution for a trench or excavation of certain geometry, the exposure concentration and then the risk can be easily calculated. This method of evaluation was demonstrated at a former bulk fuel terminal site in the San Francisco Bay region.