Evaluation of in situ biodegradation of chlorinated solvents in a fractured bedrock aquifer

Spent chlorinated solvents consisting of 1,1,1-TCA, TCE, 1,1,2-TCA, DCM as well as BTEX and asphaltic compounds are suspected to have been released from two former underground storage tanks at a Colorado Department of Transportation Materials Testing Laboratory in Denver. Release of these constituents into the highly fractured bedrock setting at the site resulted in an impacted plume that extends over approximately 1,600 feet from the suspected point of release. An evaluation of bioremedial processes was performed to determine the extent of intrinsic biodegradation processes occurring at the site and whether or not these processes could be enhanced. A program was implemented to collect: 1) field data to describe the natural attenuation process, and 2) laboratory microcosm data to determine relative rates and extents of chlorinated solvent degradation.