Containment with Monitored Natural Attenuation Results in Significant Downgradient Volatile Organic Compound Reduction from DNAPL Source Area(ABSTRACT)

摘要

RCRA Facility Investigation (RFI) activities identified dense nonaqueous-phase liquid (DNAPL) and part per million concentrations of volatile organic compounds in soil and groundwater at a facility in central Iowa. The facility formerly stored and distributed agricultural, industrial, and dry cleaning chemicals over a 15-year period beginning in 1972. Site investigation activities identified the presence of tetrachloroethene (PCE) concentrations in soil up to 1,500 mg/kg in the former storage tank area. Beneath this area, DNAPL (40% PCE, 40% xylenes, and 20% mineral spirits) was detected in the sand and gravel aquifer at the contact with the underlying shale bedrock with thicknesses measured up to 6 feet in several wells. The half-mile long area of dissolved chlorinated volatile organic compounds (VOC) in groundwater emanated with concentrations up to 100 mg/L for individual constituents.