二仁溪底泥微生物之多氯聯苯脫氯勢能研究

Evaluation of Polychlorinated Biphenyl （PCB）-Dechlorination Potential of Sediment Microbes in Erh-Jen River

為評估二仁溪底泥多氯聯苯污染之環境復育可行性，本研究採集南台灣二仁溪之中下游流域10處底泥、河水及微生物，進行多氯聯苯還原性脫氯作用之研究，脫氯實驗之培養基採用新鮮底泥混合河水所取得之底泥水，部分實驗並添加酵母萃取物(Yeast extract, YE)作為額外營養物質。實驗結果顯示，添加5g/L，YE之組別在90天之培養期間內均可完成234-三氯聯苯之脫氯作用，然而未添加YE者在160天內並無任何脫氯活性發生。所有發生脫氯作用之組別，在脫氯期間都伴隨著大量甲烷生成以及氧化還原電位下降之現象。本研究證實，多氯聯苯脫氯作用微生物確實廣泛存在於二仁溪之中下游流域中，而提供主要脫氯作用族群－－甲烷菌－－適當之生長環境正是環境中自發性脫氯作用之關鍵所在。

For an assessment of environmental remediation of polychlorinated biphenyls (PCBs) pollution in Erh-Jen River located in southern Taiwan, microorganisms from ten river sediments were collected and applied to 2,3,4-trichlorobiphenyl (2,3,4-CBp) reductive dechlorination experiments. By using natural sediment-extracted waters as cultural media, when amended with 5g/L of yeast extract, all ten sets of sediment microorganisms initiated 2,3,4-CBp dechlorination after 90 days. Without yeast extract, no set showed dechlorinating activity during a period of 160-day incubation. In all dechlorination-generation sets, dechlorination was accompanied with significant production of methane and the drop of oxidation-reduction potential (ORP). The results suggest that there were 2,3,4-CBpdechlorinating consortia in Erh-Jen River sediments. However, it also indicated that the dechlorination of 2,3,4-CBp could occur when the environmental conditions were suitable for the methanogens to be enriched.