title: Chlorinated ethene source remediation: lessons learned.
abstract: Chlorinated solvents such as trichloroethene (TCE) and tetrachloroethene (PCE) are widespread groundwater contaminants often released as dense nonaqueous phase liquids (DNAPLs). These contaminants are difficult to remediate, particularly their source zones. This review summarizes the progress made in improving DNAPL source zone remediation over the past decade, and is structured to highlight the important practical lessons learned for improving DNAPL source zone remediation. Experience has shown that complete restoration is rare, and alternative metrics such as mass discharge are often useful for assessing the performance of partial restoration efforts. Experience also has shown that different technologies are needed for different times and locations, and that deliberately combining technologies may improve overall remedy performance. Several injection-based technologies are capable of removing a large fraction of the total contaminant mass, and reducing groundwater concentrations and mass discharge by 1 to 2 orders of magnitude. Thermal treatment can remove even more mass, but even these technologies generally leave some contamination in place. Research on better delivery techniques and characterization technologies will likely improve treatment, but managers should anticipate that source treatment will leave some contamination in place that will require future management.
authors.affiliation: HydroGeoLogic, Inc, 11107 Sunset Hills Road, Suite 400, Reston, Virginia 20190, United States. hstroo@hgl.com
authors.forename: Hans F
authors.initials: HF
authors.lastname: Stroo
authors.forename: Andrea
authors.initials: A
authors.lastname: Leeson
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Marqusee
authors.forename: Paul C
authors.initials: PC
authors.lastname: Johnson
authors.forename: C Herb
authors.initials: CH
authors.lastname: Ward
authors.forename: Michael C
authors.initials: MC
authors.lastname: Kavanaugh
authors.forename: Tom C
authors.initials: TC
authors.lastname: Sale
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Newell
authors.forename: Kurt D
authors.initials: KD
authors.lastname: Pennell
authors.forename: Carmen A
authors.initials: CA
authors.lastname: Lebrón
authors.forename: Marvin
authors.initials: M
authors.lastname: Unger
mesh_terms: D052918:Environmental Restoration and Remediation / Q000379:methods*; D010539:Permeability; D013750:Tetrachloroethylene / Q000737:chemistry / Q000302:isolation & purification*; D014241:Trichloroethylene / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D014241:Trichloroethylene; D013750:Tetrachloroethylene