Integrating microbial biostimulation and electrolytic aeration to degrade POPs

描述(由申请人提供)： 多氯联苯、氯苯和二恶英等持久性有机污染物(POPs)污染的沉积物由于其广泛的用途和稳定性，几十年来一直受到环境的关注。除了扰乱底栖动物群落外，这些化合物还通过在鱼类和海洋哺乳动物等动物的脂肪组织中积累，在食物链中进行生物放大，如果食用，最终可能会影响人类。人类接触卤代持久性有机污染物可导致皮肤毒性、致畸毒性、内分泌影响、肝脏毒性、免疫毒性和致癌。虽然这些高度氯化的化合物在环境中化学稳定，但一旦它们的大部分氯被去除，就很容易降解。最初的脱氯是在厌氧环境中通过微生物还原呼吸来催化的，然后这个初始微生物过程的产物可以被氧气呼吸微生物降解和解毒。这些过程的局限性是：1)厌氧脱氯通常是缓慢和不完整的；2)在这些化合物持续存在的厌氧沉淀区，氧气的可获得性有限会抑制好氧降解。首席调查人员建议完成厌氧过程，通过原位生物强化脱氯微生物进行四氯化，然后应用低电流水解法，为氯化化合物的完全降解提供恒定的氧气水平。这种方法的创新方面包括使用具有特定活性的脱氯物种来指导厌氧脱氯途径，在不共释放有毒氯化合物的情况下扩大脱卤化接种量的独特过程，在好氧降解期间电解水以保持恒定的氧气水平，以及用于监测微生物群落的高通量分子分析。这一综合方法将优化厌氧和好氧过程，通过矿化成小分子代谢物和二氧化碳，实现氯化化合物的完全原位解毒。对受有机卤化物影响的场所实施易于处理的就地解毒过程，将减少对食物链的暴露和随后对普通公众的暴露风险。

DESCRIPTION (provided by applicant): Due to the their widespread use and stability, sediments contaminated with persistent organic pollutants (POPs) such as polychlorinated biphenyls, chlorobenzenes and dioxins have been an environmental concern for several decades. In addition to perturbing the benthic community, these compounds biomagnify in the food chain through accumulation in the fatty tissue of animals, such as fish and marine mammals, which can eventually affect humans if consumed. Exposure to halogenated POPs by humans can lead to dermal toxicity, teratotoxicity, endocrine effects, hepatotoxicity, immunotoxicity, and carcinogenesis. Although chemically stable in the environment these highly chlorinated compounds are susceptible to degradation once most of their chlorines are removed. The initial dechlorination is catalyzed in the anaerobic environment by microbial reductive respiration; the products of this initial microbial process can then be degraded and detoxified by oxygen respiring microorganisms. The limitations of these processes are: 1) anaerobic dechlorination is often slow and incomplete; 2) aerobic degradation is inhibited by limited availability of oxygen in the anaerobic sediment regions where these compounds persist. The Principal Investigators propose to complete the anaerobic process to unflanked di- through tetrachlorinated by in situ bioaugmention with dechlorinating microorganisms followed by application of low current hydrolysis to provide a constant level of oxygen for the complete degradation of the chlorinated compounds. The innovative aspects of this approach include the use of dechlorinating species with specific activities to direct the anaerobic dechorination pathways, a unique process for scaling up dehalogenating inoculum without co-release of toxic chlorinated compounds, electrolysis of water for maintaining constant oxygen levels during aerobic degradation and high throughput molecular assays for monitoring microbial communities. This integrated approach will optimize both anaerobic and aerobic processes to achieve complete in situ detoxification of chlorinated compounds through mineralization to small molecular weight metabolites and carbon dioxide. Implementation of a tractable in situ detoxification process to organohalide impacted sites will mitigate exposure to the food chain and subsequent exposure risks to the general public.