Comparative plant uptake and microbial degradation of trichloroethylene in the rhizospheres of five plant species-- implications for bioremediation of contaminated surface soils

摘要

The objective of this study was to collect data that would provide a foundation for the concept of using vegetation to enhance in situ bioremediation of contaminated surface soils. Soil and vegetation (Lespedeza cuneata, Paspalum notatum, Pinus taeda, and Solidago sp.) samples from the Miscellaneous Chemicals Basin (MCB) at the Savannah River Site were used in tests to identify critical plant and microbiological variables affecting the fate of trichloroethylene (TCE) in the root zone. Microbiological assays including phospholipid acid analyses, and (sup 14)C-acetate incorporation were conducted to elucidate differences in rhizosphere and nonvegetated soil microbial communities from the MCB. The microbial activity, biomass, and degradation of TCE in rhizosphere soils were significantly greater than corresponding nonvegetated soils. Vegetation had a positive effect on microbial degradation of (sup 14)C-TCE in whole-plant experiments. Soils from the MCB containing Lespedeza cuneata, Pinus taeda, and Glycine max mineralized greater than 25% of the (sup 14)C- TCE added compared with less than 20% in nonvegetated soils. Collectively, these results provide evidence for the positive role of vegetation in enhancing biodegradation.