MONITORING REDUCTIVE DECHLORINATION IN A TETRACHLOROETHENE-CONTAMINATED SITE

摘要

Knowledge about pollutant-degrading microbial community is a crucial factor for assessing and monitoring the process of bioremediation at contaminated sites. The objectives of the study are to monitor the tetrachloroethene (PCE)-dechlorinating microbial population and evaluate dechlorinating processes by supplying lactate as an electron donor in a PCE-contaminated site. Monitoring well Ex2, which was contaminated with high concentration of PCE and showed positive responses to Dehalococcoides ethenogenes 16S ribosomal DNA (rDNA) by PCR detection was chosen to enhance the natural attenuation on contaminated site. Slurry sediments of well Ex2 and lactate were added into well Ex3, in which D. ethenogenes was not detected. After six months, PCE significantly decreased with the initial rate of 8.39 and 3.31 μg/l/day in groundwater of well Ex2 and Ex3, respectively. The dehalogenase gene tceA was consistently detected in slurry sediments of well Ex2 and Ex3 by PCR assay. The results suggested that D. ethenogenes might halorespire with PCE in well Ex2 and Ex3. This study provided the evaluating protocols which assess potentiality of bioremediation and the extent of dechlorination processes in a contaminated site. This study may provide useful information for determination of the suitable remediation methods.