Distribution of key microbes and functional genes in the chlorinated ethene-contaminated groundwater

Chlorinated ethenes are a group of chemicals commonly found in contaminated groundwater. In-situ bio-remediation is a popular and competitive technology for contaminated sites, and the one of the factors to influence the effectiveness of remediation is presence of degrading microbes in the sites. This study is aimed to detect the presence of targeted chemicals and microbes in 37 wells in two sites contaminated with chlorinated ethenes. Results of microbial analyses with SybrGreen-qPCR showed that �genus Dehalococcoides, which had the ability to degrade chlorinated ethene, was 0.0001~14.58% of total bacteria, and total chlorinated ethenes of larger than 0.8 mg/L may inhibit the growth of genus Dehalococcoides. Abundance of vcrA gene, capable of �degradation of chlorinated ethenes to ethene, is positive correlated with the abundance of �genus Dehalococcides (R2 = 0.72) and the concentration of chlorinated ethenes. The results of study suggested that the two contaminated sites studied have the potential for �bio-remediation.