MICROBIAL DEGRADATION AND INTERACTIONS OF PAH AND SOIL

该项目的总体目标是评估 微生物对环境中多环芳烃(PAH)去向的影响 土壤环境随时间的变化，以便更好地确定潜在的 暴露于人类或土著生物的健康风险。微生物 多环芳烃的新陈代谢可导致：(1)通过- 产品(可能比母公司或多或少有毒或流动的产品 化合物)和(2)可随后形成的副产品 代谢然后矿化成二氧化碳(通常由其他微生物)。一个 母体化合物或代谢物的另一种命运是 多环芳烃与土壤有机质(SOM)的相互作用 通过吸附过程并入SOM(Walton等人，1994)。这个 后者最近已在我们的实验室和其他实验室进行了演示。我们现在 建议确定这些问题的大小和机制路径 与环境样品的相互作用。如果在SOM中加入多环芳烃 是土壤中多环芳烃的重大命运，它将深刻地影响有毒物质 多环芳烃和多环芳烃副产物的性质。先验的是，成立公司是 可能会降低毒性。如果是这样的话，这条路线可以提供一个简单的，成本 有效的生物修复策略。将进行实验，以 调查土壤和微生物群落的哪些特征可以 冲击性生物降解与并入。为了实现这些目标， 提出了以下目标： 1.评估微生物介导的降解与 在土壤有机碳基质中加入一系列多环芳烃(3， 4、5和6环：菲、芘、黄原烯和苯并(A)芘)和 它们的微生物降解产物。 2.调查多环芳烃及其化合物的并入程度 将产品降解到SOM中，并了解合并情况 用~(13)C-核磁共振评价~(13)C-多环芳烃与土壤有机质的结合机理。 3.估计退化和合并进程对 毒性(用微毒素测定)和致突变性(用MUTATOX测定 TM)。 4.将退化和/或土壤相互作用的速度和程度与 化学物质、土壤和微生物群落的特征。 5.制定生物修复策略。

The overall goal of this project is to assess the influence of microorganisms on the fate of polynuclear aromatic hydrocarbons (PAH) in soil environments over time, in order to better determine the potential health-risk exposure to human or indigenous organisms. The microbial metabolism of PAHS can result in; (1) the accumulation of more polar by- products (that may be more or less toxic or mobile than the parent compound) and (2) the formation of by-products that can be subsequently metabolized then mineralized to Co2 (usually by other microorganisms). An alternative fate for either parent compounds or metabolites is the interaction of PAHs with soil organic matter (SOM) that may lead to incorporation into SOM via sorption processes (Walton et al., 1994). The latter has recently been demonstrated in our laboratory and others. We now propose to determine both the magnitude and mechanistic pathways of these interactions with environmental samples. If incorporation of PAHs into SOM is a significant fate of PAHs in soil, it will profoundly impact the toxic properties of both PAHs and PAH by-products. A priori, incorporation is likely to reduce toxicity. If so, this route could provide a simple, cost effective strategy for bioremediation. Experiments will be conducted to investigate which characteristics of the soil and microbial community can impact biodegradation versus incorporation. To achieve these goals, the following aims are proposed; 1. Assess the relateive rates of microbially mediated degradation versus incorporation into the soil organic carbon matrix for a range of PAHs (3, 4, 5, and 6 ring: phenanthrene, pyrene, chrysene, and benzo(a)pyrene) and their microbial degradation products. 2. Investigate the extent of incorporation of the PAHs and their degradation products into SOM and gain insight into incorporation mechanisms by using 13C-NMR to evaluate binding of 13C-PAH to SOM. 3. Estimate the impact of degradation and incorporation processes on toxicity (measured with MICROTOX) and mutagenicity (measured with MUTATOX tm). 4. Relate rates and magnitude of degradation and/or soil interactions to the characteristics of the chemical, the soil, and the microbial community. 5. Develop bioremediation strategies.