Project Summary (2000-2006)

This project is combining gene probe analysis with laboratory and field studies to assess the effect of an innovative aquifer remediation technology, co-solvent flushing (using 95 percent ethanol), on the indigenous microorganisms. In addition to studying indicators of ecosystem functioning, this project is also investigating the potential of the microbial populations present at a specific site (originally contaminated with perchloroethylene (PCE) and trichloroethylene (TCE)) to degrade residual contaminant and is determining the degradation products remaining after treatment. The specific hypothesis being tested are: 1) microorganisms present at the site are capable of rebounding to their original diversity and activity; and 2) these rebounded microorganisms are capable of degrading any contaminant and daughter products remaining after flushing. Specific studies are measuring prokaryotic gene concentrations before and after treatment as ecological and biodegradative indicators. These indicators can then be related to laboratory and in situ microcosm results in order to provide a means of assessing the natural degradative ability of the communities present. In other studies, in situ microcosms are being built and placed at various locations at a PCE contaminated site. In situ rates of substrate transformation, product formation, and electron donor/acceptor utilization can then be measured and compared to the laboratory microcosm studies as another assessment tool for determining the activity of the microorganisms present before and after flushing at the site.