PNNL

Abstract

Deep vadose zone contamination is a significant issue facing the U.S. Department of Energy’s (DOE) Office of Environmental Management (EM). Contamination in the deep vadose zone is isolated from exposure such that direct contact is not a factor in risk to human health and the environment; rather, movement of contamination from the deep vadose zone to the groundwater creates the potential for exposure and risk to receptors. Transport of deep vadose zone contamination and discharge to the groundwater creates the potential for exposure and risk to receptors, so limiting flux to groundwater is key for protection of groundwater resources. Remediation approaches for the deep vadose zone need to be considered within the regulatory context, targeted at mitigating the source of contamination and reduce contaminant flux to groundwater. This paper reviews the processes for deep vadose zone metal and radionuclide remediation as well as challenges and opportunities for implementation.