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首页> 外文学位 >Enhancement of site specific anaerobic reductive dechlorination of polychlorinated biphenyls.
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Enhancement of site specific anaerobic reductive dechlorination of polychlorinated biphenyls.

机译：增强特定位置的多氯联苯厌氧还原性脱氯。

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摘要

Polychlorinated biphenyls (PCBs) are widespread, priority pollutants which persist in the environment and tend to bioaccumulate. Toxicological data has shown that PCBs elicit a spectrum of toxic responses in both humans and laboratory animals. These characteristics have implicated PCBs in the decline of fish eating birds and mammals. Although they are considered recalcitrant microorganisms can degrade PCBs. The bioremediation of PCBs has been conceptualized as a sequential process involving the anaerobic reductive dechlorination of PCBs followed by aerobic mineralization. This has not been realized because the full potential of anaerobic reductive dechlorination of PCBs is rarely achieved. This dissertation describes investigations designed to identify and overcome site specific limitations to the maximum extent of anaerobic PCB dechlorination.; Because PCBs are of industrial origin they are usually associated with related environmental pollutants. Residual petroleum hydrocarbons and other non-polar contaminants were found to reduce both the rate and extent of PCB dechlorination. This response was identical to that which would be predicted based solely on the reduction of PCB solution concentrations due to an innocuous sorptive phase. This suggests that petroleum hydrocarbons reduce the bioavailability of PCBs to dechlorinating microorganisms.; Heavy metals are the most commonly observed co-contaminant associated with PCBs. Anaerobic reductive dechlorination of PCBs in laboratory assays were adversely affected by zinc solution concentrations less than or equal to those found at many PCB contaminated sites. We therefore tested two means of alleviating metal toxicity: precipitation (adding FeSO{dollar}sb4{dollar}) and chelation (adding citrate or EDTA). Metal toxicity was reversed by additions of EDTA or citrate; however, in slurries amended with FeSO{dollar}sb4{dollar} dechlorination was enhanced. Subsequent experiments designed to elucidate the mechanism of enhancement suggest that sulfate stimulates the growth of sulfate reducing organisms responsible for PCB dechlorination, while Fe{dollar}sp{lcub}2+{rcub}{dollar} reduces sulfide bioavailability and hence toxicity. Ferrous sulfate is an inexpensive, innocuous compound which could be utilized to overcome factors limiting both the extent of in-situ dechlorination in metal and non-metal contaminated sediments as well as the implementation of sequential anaerobic/aerobic biotreatment systems.
机译：多氯联苯（PCB）是广泛存在的优先污染物，其在环境中持续存在并易于生物累积。毒理学数据表明，多氯联苯在人类和实验动物中均引起多种毒性反应。这些特征牵涉到多氯联苯在食鱼鸟类和哺乳动物数量下降中的作用。尽管它们被认为是顽强的微生物，但它们可以降解PCB。多氯联苯的生物修复已被概念化为一个顺序过程，涉及多氯联苯的厌氧还原脱氯，然后进行有氧矿化。由于几乎没有实现PCB厌氧还原性脱氯的全部潜力，因此尚未实现。本文描述了旨在识别和克服特定位置限制的研究，以最大程度地进行厌氧PCB脱氯。由于多氯联苯是工业来源的，它们通常与相关的环境污染物有关。发现残留的石油碳氢化合物和其他非极性污染物会降低PCB脱氯的速度和程度。该响应与仅基于无害吸附相导致PCB溶液浓度降低所预期的响应相同。这表明石油碳氢化合物会降低多氯联苯对微生物进行脱氯的生物利用度。重金属是与PCB相关的最常见的共污染物质。在实验室分析中，PCB的厌氧还原性脱氯受到锌溶液浓度小于或等于在许多PCB污染场所发现的浓度的不利影响。因此，我们测试了两种减轻金属毒性的方法：沉淀（添加FeSO {sb4 {sb4 {dollar}）和螯合（添加柠檬酸盐或EDTA）。加入EDTA或柠檬酸盐可逆转金属毒性；但是，在用FeSO {sdol4sb4 {dollar}修正的浆料中，脱氯作用增强了。旨在阐明增强机制的后续实验表明，硫酸盐刺激负责PCB脱氯的硫酸盐还原生物的生长，而Fe {dollar} sp {lcub} 2+ {rcub} {dollar}降低了硫化物的生物利用度，因此降低了毒性。硫酸亚铁是一种廉价，无害的化合物，可用于克服限制金属和非金属污染沉积物中原位脱氯程度以及实施连续厌氧/好氧生物处理系统的因素。

著录项

  • 作者

    Zwiernik, Matthew John.;

  • 作者单位

    Michigan State University.;

  • 授予单位 Michigan State University.;
  • 学科 Environmental Sciences.; Biology Microbiology.
  • 学位 Ph.D.
  • 年度 1998
  • 页码 134 p.
  • 总页数 134
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境科学基础理论;微生物学;
  • 关键词

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