In human health risk assessment, indoor vapor inhalation exposure concentration evaluation methods based on field measurements using multiple environmental media, including soil, soil gas and indoor air have been proposed to quantify contaminant fluxes and their vapor intrusion from soil to buildings. However, only soil and indoor air are currently considered to evaluate the impact of vapor intrusion in domestic guidelines. This study assessed indoor vapor inhalation exposure concentration and conducted human health risk assessment for BTEX and TPH in soil, soil gas and indoor air samples collected from petroleum-contaminated sites. Calculated vapor inhalation risks based on soil concentrations were approximately 10²-10³ times higher than those based on soil gas and indoor air. Additionally certain compounds, such as benzene, were not detected in soil samples, indicating the potential omission of target analytes. Vapor inhalation risks based on soil gas and indoor air were generally comparable, whereas naphthalene was detected only in indoor air samples, suggesting potential interference from non-soil sources, such as external infiltration. These results highlight the essential role of soil gas measurements in accurately assessing the vapor intrusion pathway.

Keywords: Human health risk assessment, Soil vapor intrusion, soil gas