[CPEO-MEF] Natural Attenuation Study at Twin Cities AAP

[Lenny Siegel <lsiegel@cpeo.org>]

Evaluation of the Protocol for Natural Attenuation of Chlorinated
Solvents: Case Study at the Twin Cities Army Ammunition Plant (EPA
600-R-01-025). 

EPA's Office of Research and Development carried out an independent
evaluation of the Technical Protocol for Evaluating Natural Attenuation
of Chlorinated Solvents in Ground Water (EPA/600/R-98/128). The Protocol
was developed around case studies on relatively small plumes in sand
aquifers. Staff in the Regions wished to know if the Protocol could be
usefully applied to large plumes, or to plumes in aquifers in fractured
consolidated rock. The results show that the Protocol was successful in
predicting the development of the ground-water plume at the Twin Cities
Army Ammunition Plant (TCAAP). The screening analysis in the Protocol
predicts that the geochemical environment at TCAAP is not favorable to
rapid reductive dechlorination. The modeling portion of the study
indicated that the current ground-water plume should be expected when
the rate of reductive dechlorination is slow. The study also shows that
natural biodegradation complements the ongoing efforts to extract
contaminated ground water at the source, and should greatly reduce the
time required to reduce the concentration of contaminants to U.S. EPA
drinking water standards (March 2001, 49 pages). View or download at 
http://www.epa.gov/ada/download/reports/epa_600_r01_025.pdf . 
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Lenny Siegel
Director, Center for Public Environmental Oversight
c/o PSC, 222B View St., Mountain View, CA 94041
Voice: 650/961-8918 or 650/969-1545
Fax: 650/961-8918
lsiegel@cpeo.org
http://www.cpeo.org

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