Biosafety of Bioremediation Approaches in a Tetrachloroethylene-Contaminated Environment
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Ross,N.,A-M.I. Abbey, S. Lesage, T.V. McDaniel, P.A. Martin, E.A. Edwards, and D.W. Major 2003"Biosafety of Bioremediation Approaches in a Tetrachloroethylene-Contaminated Environment, "Paper A-20, in: V.S. Magar and M.E. Kelley (Eds.), In Situ and On-Site Bioremediation 2003. Proceedings of the Seventh International In Situ and On-Site Bioremediation Symposium (Orlando, FL; June 2003)

To assess whether the injection of an adapted culture in groundwater (bioaugmentation) is as biosafe as stimulating the indigenous bacteria (biostimulation) or observing natural processes (natural attenuation), a large-scale aquifer (6.0×2.4×1.8 m) was divided in three lanes for a comparative study in a tetrachloroethylene(PCE)-contaminated groundwater. The biodegradation of PCE, the fate of injected and indigenous bacteria, and the ecotoxicological responses were monitored. Results from the first 250 days confirmed that bioaugmentation was effective for reductive dechlorination to ethene, whereas cis-DCE remained in the effluent from the biostimulation lane and no degradation products were measured in the natural attenuation lane. The bacterial density was consistent over time and space in the model aquifer, but partitioning between groundwater (5 log.mL-1) and sand particles (12 log.g-1) suggested that the active population was sessile. As a potential receptor of groundwater through resurgence into wetlands, a model amphibian was chronically exposed to effluents from the three lanes; although the froglets had a significant higher weight compared to the controls, the survivorship and metamorphic transformation were not significantly affected by the effluents. This information will be used to help define regulatory requirements for in situ bioremediation approaches.

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