Enrichment of anaerobic polychlorinated biphenyl dechlorinators from sediment with iron as a hydrogen source.
Enrichment of anaerobic polychlorinated biphenyl dechlorinators from sediment with iron as a hydrogen source.
复制标题
DOI：
10.1016/j.watres.2004.11.009
复制
发表时间：
2005-02
期刊：
影响因子：
12.8
通讯作者：
J. Ryšavý;T. Yan;P. Novak
中科院分区：
文献类型：
--
作者：
J. Ryšavý;T. Yan;P. Novak
关于厌氧多氯联苯（PCB）脱氯知之甚少，尽管人们认为一些微生物能够呼吸PCB，从PCB脱氯中获得生长所需的能量。如果是这样的话，修改适当的电子供体污染的沉积物应刺激脱氯。以巴尔的摩港河口沉积物为微生态系统，研究了添加易修饰的电子供体元素铁（Fe 0）对多氯联苯（PCB）同系物3，4，5-三氯联苯（3，4，5-CB）和2，2 ′，3，4，4 ′，5，5 ′-七氯联苯（2，2 ′，3，4，4 ′，5，5 ′-CB）微生物脱氯的影响.结果表明，投加0.1gFe0/g底泥，可使双边帕拉氯的去除滞后时间缩短约100天。由于Fe 0是阴极氢（H2）的来源，还测试了直接H2添加到沉积物微观世界的效果。在顶空中加入0.001大气压的H2产生与加入0.1g Fe 0/g相同的脱氯活性和减少的滞后时间。较高浓度的Fe 0或H2增加了脱氯前的滞后。其他结果表明，碱性pH值（约7.5），高[Fe 2 +]（3.3g/L）或HS−（约0.1mg/L总硫化物）抑制脱氯。Fe 2+、OH−和HS−浓度升高是Fe 0氧化或微生物活性增加（甲烷生成、同型乙酸生成和硫酸盐还原）的产物，这两种情况都是由于大量Fe 0或H2进入沉积物的结果。这项研究表明，不仅可以通过添加电子供体来刺激多氯联苯的脱氯作用，而且还意味着通过连续添加低浓度的H2来富集脱氯剂，类似于其他已知的脱氯剂，例如脱卤呼吸剂Dehalococcoides ethenogenes。这些结果表明，直接添加控制量的Fe 0沉积物可能是一种有效的补救工具，以减少在多氯联苯影响的网站脱氯之前的滞后期。他们还认为，可以使用与已知的呼吸脱卤剂类似的技术来富集多氯联苯脱氯剂。
Little is known about anaerobic polychlorinated biphenyl (PCB) dechlorination, although it is believed that some microorganisms are capable of respiring PCBs, gaining energy for growth from PCB dechlorination. If this is the case, the amendment of appropriate electron donors to contaminated sediment should stimulate dechlorination. The effect of elemental iron (Fe0) addition, an easily amended electron donor, on the microbial dechlorination of the PCB congeners 3,4,5-trichlorobiphenyl (3,4,5-CB) and 2,2′,3,4,4′,5,5′-heptachlorobiphenyl (2,2′,3,4,4′,5,5′-CB) was investigated in microcosms containing estuarine sediment from Baltimore Harbor. Results showed that the addition of 0.1g Fe0/g sediment reduced the lag time for removal of doubly flanked para chlorines by approximately 100 days. Because Fe0is a source of cathodic hydrogen (H2), the effect of direct H2addition to sediment microcosms was also tested. The addition of 0.001 atm H2in the headspace generated the same dechlorination activity and reduction in lag time as the addition of 0.1g Fe0/g. Higher concentrations of Fe0or H2increased the lag prior to dechlorination. Additional results showed that an alkaline pH (⩾7.5), high [Fe2+] (3.3g/L), or HS−(⩾0.1mg/L total sulfide) inhibited dechlorination. Elevated concentrations of Fe2+, OH−, and HS−are products of Fe0oxidation or increased microbial activity (methanogenesis, homoacetogenesis, and sulfate reduction), both of which would result from the amendment of large quantities of Fe0or H2to sediment. This research shows that not only can PCB dechlorination be stimulated through the addition of electron donor, but implies that the dechlorinators are enriched by the continuous addition of low concentrations of H2, similar to other known dechlorinators, such as the dehalorespirer Dehalococcoides ethenogenes. These results suggest that the direct addition of controlled amounts of Fe0to sediments may be an effective remediation tool to reduce the lag period prior to dechlorination at PCB-impacted sites. They also suggest that PCB dechlorinators may be enriched using techniques similar to those used with known dehalorespirers.