In uncontaminated environments, chlorinated natural organic matter (Cl-NOM) can act as an electron acceptor for organohalide-respiring bacteria. It is unknown, however, whether different types of Cl-NOM are preferentially dechlorinated or whether enrichment with Cl-NOM affects the ability of bacteria to dechlorinate contaminants. In this research NOM was extracted from sediment, fractionated based on hydrophobicity, and either amended to polychlorinated biphenyl-contaminated soil directly or chlorinated and then amended to soil. Amendments of the least hydrophobic Cl-NOM fraction were dechlorinated most rapidly, followed by the moderately hydrophobic Cl-NOM fraction. Soil that had been enriched on the moderately hydrophobic fraction of Cl-NOM was also capable of faster dechlorination of the contaminants trichloroethene and tetrachlorobenzene. Community analysis of the soil during enrichment showed that some known organohalide-respiring bacteria were present and may have played a role in dechlorination; nevertheless, many bacteria appeared to be enriched during both Cl-NOM and contaminant dechlorination. In addition, the quantities of two haloalkane dehalogenase genes increased during enrichment on Cl-NOM. These results show for the first time that Cl-NOM can prime contaminant dechlorination and also suggest that hydrolytic dechlorination processes were involved in both Cl-NOM and contaminant dechlorination.

中文翻译：

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多种氯化物和脱氯基因通过对氯化天然有机物组分的修正而富集。

在未污染的环境中，氯化天然有机物（Cl-NOM）可以用作呼吸有机卤化物的细菌的电子受体。但是，尚不清楚不同类型的Cl-NOM是否优先脱氯，或者用Cl-NOM富集是否会影响细菌对污染物进行脱氯的能力。在这项研究中，NOM是从沉积物中提取的，并根据疏水性进行分级，然后直接修改为多氯联苯污染的土壤，也可以先经过氯化处理再修改为土壤。疏水性最低的Cl-NOM馏分的修正最迅速地脱氯，其次是中等疏水性的Cl-NOM馏分。富含Cl-NOM中等疏水性部分的土壤也能够更快地将污染物三氯乙烯和四氯苯脱氯。富集过程中对土壤的群落分析表明，存在一些已知的可吸入有机卤化物的细菌，并可能在脱氯过程中发挥了作用。但是，在Cl-NOM和污染物脱氯过程中，许多细菌似乎都富集了。另外，在Cl-NOM上富集期间，两个卤代烷脱卤酶基因的数量增加。这些结果首次表明，Cl-NOM可以引发污染物脱氯，也表明水解脱氯过程与Cl-NOM和污染物脱氯有关。Cl-NOM富集期间，两个卤代烷脱卤酶基因的数量增加。这些结果首次表明，Cl-NOM可以引发污染物脱氯，也表明水解脱氯过程与Cl-NOM和污染物脱氯有关。Cl-NOM富集期间，两个卤代烷脱卤酶基因的数量增加。这些结果首次表明，Cl-NOM可以引发污染物脱氯，也表明水解脱氯过程与Cl-NOM和污染物脱氯有关。