||Battelle, Columbus, OH.; Department of Energy, Washington, DC.; Environmental Protection Agency, Washington, DC.; Department of Defense, Washington, DC.; National Aeronautics and Space Administration, Washington, DC.
Dense, nonaqueous-phase liquid (DNAPL) contaminants are a challenge to characterize and remediate at many sites where such contaminants have entered the aquifer due to past use or disposal practices. Chlorinated solvents, comprised of chlorinated volatile organic compounds (CVOCs), such as trichloroethylene (TCE) and perchloroethylene (PCE), are common DNAPL contaminants at sites where operations, such as aircraft maintenance, dry cleaning, metal finishing, and electronics manufacturing historically have occurred. In the past, because of the difficulty in identifying DNAPL source zones, most remediation efforts focused on controlling the migration of dissolved CVOC plumes. In recent years, many site owners have experienced success in locating DNAPL sources. DNAPL source remediation is thought to be beneficial because once the source has been significantly mitigated, the strength and duration of the resulting plume can potentially be lowered in the long term, and sometimes in the short or intermediate term as well.