Location: Whitehall, New York
Regulatory Program: NYSDEC Regulations
Duration: 1998 to 1999
Summary: Monitored Natural Attenuation “Lines of Evidence” Demonstration
During previous employment, Mr. Peterson designed, implemented and managed an investigation to evaluate the applicability of natural attenuation as a remedy for chlorinated solvent- and benzene, toluene, ethylbenzene and xylene (BTEX)-impacted groundwater at this former metalworking facility and adjacent municipal firefighter training area. The investigation was completed in accordance with the Technical Protocol for Implementing Monitored Natural Attenuation for Chlorinated Solvents in Ground Water (USEPA, September 1998).
One objective of this project was to provide a technical basis for future cost recovery. In this case, responsible parties included both the State of New York and the private parties. The private parties were interested in determining whether a less-costly alternative than the pump and treat remedy preferred by the New York State Department of Environmental Conservation (NYSDEC) would be effective. The September 1998 USEPA protocols were applied because they were derived based largely on experience at sites with similar sources of contamination (fire training areas on United States Air Force bases).
Specific activities conducted included thoroughly evaluating hydrogeologic conditions and mapping the distributions of terminal electron acceptors and other geochemical indicators (dissolved oxygen, nitrate, ferrous iron, sulfate, methane, oxidation/reduction potential, specific conductance), electron donors (BTEX and organic carbon), chlorinated “parent” and degradation compounds/byproducts (dichloroethenes, vinyl chloride, ethane, ethane and chloride). Contaminant half-lives were estimated, based on their distribution in groundwater and the calculated groundwater velocity. The BIOCHLOR model was utilized to estimate the downgradient extent of contamination.
Results of the natural attenuation assessment were summarized in a Remedial Action Workplan to NYSDEC. The workplan presented a strong case for implementing natural attenuation and a proposed monitoring program, based upon the three “lines of evidence” required in the USEPA protocol. Although NYSDEC subsequently decided to pursue an active remedy at this site (primarily with State funds), legal counsel for the private party client was satisfied with the technical evaluation and indicated that the client’s objectives for the project had been met.