- Featured Initiatives
- Per- and Polyfluoroalkyl Substances (PFASs)
- Range Sustainment
- Energy Assurance and Resilience
- Cleanup Initiatives
- Munitions Response Initiatives
- Green Manufacturing and Maintenance
Vapor Intrusion represents a major concern at sites contaminated with volatile chemicals, such as trichloroethene (TCE), that extend beneath planned or existing buildings. Vapor intrusion into buildings is driven by natural processes (including advection, diffusion, biodegradation, and pressure fluctuations caused by wind, temperature, and diurnal cycles), as well as human factors, such as occupant activities in buildings. Vapor intrusion can pose significant long- and short-term human health risks, and this risk pathway is the driver for many corrective action plans and site cleanups.
Chlorinated solvents such as TCE are prevalent contaminants in groundwater and soils at DoD sites, and vapor intrusion has become an increasing concern as regulatory interest has grown. While the development of methods for assessing and measuring vapor intrusion has been underway for several years, research on the underlying science governing the vapor intrusion pathway has been lacking. Tremendous uncertainty remains regarding how best to assess the vapor intrusion pathway. The monitoring required at sites where vapor intrusion is suspected can be expensive and time-consuming, especially at large industrial buildings. Temporal and spatial variability can be very large, complicating vapor intrusion assessments, and it is challenging to predict and measure the fate and transport of vapors in soil.
SERDP research efforts focus on developing a more robust understanding of vapor intrusion and its significance. Researchers are investigating the processes associated with the emission of chemical vapors from dissolved chemical groundwater plumes and entrapped DNAPL sources; their transport and attenuation in heterogeneous vadose zones; and their entry to indoor air. Integrated field-scale, lab-scale, and modeling studies are included.
Demonstration efforts under ESTCP are focused on improving the current sampling methodology and risk assessment approach for vapor intrusion assessments. Spatial and temporal variability in volatile organic compound (VOC) concentrations have a significant impact on vapor intrusion investigations. Field methods to assess vapor intrusion potential are being studied to support cost-effective site characterizations.
Over time, an improved understanding of the vapor intrusion pathway from contaminated groundwater, and the development and demonstration of improved sampling methods, will provide more accurate prediction, monitoring, and management tools. The ultimate goal of these efforts is to provide more cost-effective protection of human health.
Vapor Intrusion Workshop Report:
Vapor Intrusion into Indoor Air from Contaminated Groundwater (2014)