Project 4 - Design Principles and Field-Deployable Models for Economical Remediation of Dioxin-Contaminated Sites

项目摘要：多氯二苯并对二恶英和二苯并呋喃(PCDD/FS，也缩写为 多氯二苯并二恶英/氟)是最具挑战性的环境污染物之一。在过去的20年里，厌氧 微生物，如麦卡氏嗜盐球菌和富集菌已被证明使用许多 作为电子受体的二恶英/二恶英。在实验室条件下，这些有机卤化物的呼吸速率 呼吸菌(OHRB)产生几个月到几年的PCDD/F半衰期。因此，人力厅，如果 在更具侵入性的解决方案，如 由于成本或其他因素，疏浚和封顶是不可行的。麦卡蒂氏丝虫的呼吸能力 多氯二苯并二恶英/二恶英与大量含钴蛋白质密切相关(主要是还原脱卤酶- Rdhas)，与钴蛋白打捞途径相关的基因和蛋白质，以及氢酶-TO 利用电子给体(H2)。这三个都是呼吸复合体的关键亚单位。Cobalamins是Corrinoid (含四个还原的吡咯环，环中心为钴的化合物) 以5，6-二甲基苯并咪唑(5，6-DMBI)为底物。以氰化物为钴上配体的氯化钴称为 CN-Cb1或维生素B12(B12)。到目前为止，所有已知的PCDD/F呼吸器都是Cbl的营养缺陷症。它们不能合成 并必须使用Cbl打捞路径打捞它。然而，所有麦卡氏菌都属于Chloroflei门 在所有已知的细菌和古菌中，拥有最多的含钴基因(主要是rdhs)。这个 人力厅在两个超级基金地点--密歇根州蒂塔瓦西和萨吉诺河--存在的可能性(tr/sr)， 新泽西州的帕塞伊克河(PR)也很高。我们的工作已经在PR中确定了一个主要的系统型，PRdao 地点。总体而言，这些OHRB结合了包括活性碳(AC)、氢气释放在内的修正案 化合物(HRC)和B12有可能降低总体毒性等效商(TEQ)和 与多氯二苯并呋喃相关的健康风险。这种基于交流的方法已经在为其他人实施 有机卤化物，如多氯联苯。综合数学模型在发展中起着关键作用 多氯二苯并二恶英/氟修复的最佳解决方案。因此，该项目有以下四个具体目标：一) 量化在存在外源B12、HRC、D的情况下综合修复多氯二苯并二恶英的参数。 Mccartyi和AC，II)确定了天然的OHRB和Rdhs介导的脱氯和解毒途径 Tr/sr/pr超级基金站点的PCDD/F，III)确定AC、生物增强和盐度对 本地PCDD/F-脱氯OHRB、脱氯途径和微观世界中的速率，四)发展和 验证涉及生物和非生物干预的多氯二苯并二恶英/氟的特定地点综合补救模型。这 新的综合模型将集体知识集成到预测减少的数学工具中 在TEQ和健康风险方面对干预措施的反应。总体而言，该项目提供了新颖而强大的方法， 多氯二苯并二恶英的经济修复的设计原则和特定场地模型。

PROJECT SUMMARY: Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs, also abbreviated as PCDD/F) are among the most challenging environmental contaminants. Over the past 20 years, anaerobic microorganisms such as Dehalococcoides mccartyi and enrichments have been shown to use a number of PCDD/Fs as electron acceptors. Under laboratory conditions, the respiration rates of these organohalide respiring bacteria (OHRB) yield PCDD/F half-lives of the order of months to a few years. Hence, OHRB, if stimulated, can play a larger role in attenuating PCDD/Fs in situations where more intrusive solutions such as dredging and capping are not practicable because of cost or other factors. The ability of D. mccartyi to respire PCDD/Fs is closely linked to the high numbers of cobalt-containing proteins (mostly reductive dehalogenases - RdhAs), the genes and proteins associated with the salvaging pathway for cobalamins, and hydrogenases - to utilize the electron donor (H2). All three are critical subunits of the respiration complex. Cobalamins are corrinoids (compounds containing four reduced pyrrole rings with cobalt at the center of the ring) with 5,6- dimethylbenzimidazol (5,6-DMBI) as the lower ligand. A Cbl with cyanide as the upper ligand of cobalt is called CN-Cbl or vitamin B12 (B12). All PCDD/F respirers known so far are auxotroph for Cbl. They cannot synthesize Cbl and must salvage it using the Cbl salvage pathway. Yet, Chloroflexi – the phylum all D. mccartyi belong to has the highest number of cobalt-containing genes (mostly rdhs) among all known bacteria and archaea. The potential for the presence of OHRB at the two Superfund sites - Tittabawassee and Saginaw Rivers, MI (TR/SR), and Passaic River, NJ (PR) is high. Our work has already identified a dominant phylotype, PRdAO, at the PR site. Overall, these OHRB combined with amendments including activated carbon (AC), hydrogen release compounds (HRC), and B12 have the potential to reduce the overall toxicity equivalency quotient (TEQ) and health risks associated with PCDD/Fs. Such AC-based approaches are already being implemented for other organohalides such as polychlorinated biphenyls. Integrative mathematical models play a key role in developing optimal solutions for PCDD/F remediation. Accordingly, this project has the following four specific aims: i) Quantify the parameters for integrative remediation of PCDD/Fs in the presence of exogenous B12, HRC, D. mccartyi, and AC, ii) Identify native OHRB and Rdhs-mediated pathways for dechlorination and detoxification of PCDD/Fs at the TR/SR/PR Superfund sites, iii) Determine the effect of AC, bioaugmentation, and salinity on native PCDD/F-dechlorinating OHRB, dechlorination pathways, and rates in microcosms, iv) Develop and validate site-specific integrative remediation models for PCDD/F involving biotic and abiotic interventions. This new comprehensive model integrates the collective knowledge into a mathematical tool for predicting reduction in TEQ and health risk in response to interventions. Overall, this project provides novel and powerful approaches, design principles, and site-specific models for economical remediation of PCDD/Fs.