ABSTRACT
U.S. Environmental Protection Agency (EPA) regulations under the Resource Conservation and Recovery Act (RCRA) have required soil-pore liquid and soil-core monitoring at hazardous waste land treatment facilities since the land disposal regulations were promulgated in 1980 and 1982 (U.S EPA, 1980, 1982). To date, the regulations have not explicitly required vadose zone monitoring for RCRA hazardous waste landfills, surface impoundments, and waste piles. In 1988, however, the EPA proposed to amend the ground-water monitoring regulations to give RCRA permit writers (federal and state regulators) discretion to require vadose zone monitoring at landfills, surface impoundments, and waste piles if such monitoring would aid in the early detection of migrating contaminants (U.S. EPA, 1988).
