MICROBIAL DEGRADATION AND INTERACTIONS OF PAH AND SOIL

该项目的总体目标是评估 微生物对多环芳烃（PAH）的命运 随着时间的推移，土壤环境，以更好地确定潜在的 对人类或土著生物体的健康风险接触。 微生物 多环芳烃的代谢可导致：（1）通过- 产品（毒性或移动的可能比母体多或少 （2）生成的副产物，可以随后 代谢然后矿化为CO2（通常通过其他微生物）。 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）的相互作用可能导致 通过吸附过程掺入SOM中（Walton等人，1994年）。 的 后者最近在我们的实验室和其他实验室得到了证明。 我们现在 建议确定这些的幅度和机制途径， 与环境样品的相互作用。 如果将多环芳烃掺入SOM 是土壤中多环芳烃的一个重要归宿，它将深刻影响土壤中的有毒物质， 多环芳烃和多环芳烃副产物的性质。 先验地，合并是 可以减少毒性。 如果是这样，这条路线可以提供一个简单的，成本 生物修复的有效策略。 将进行实验， 研究土壤和微生物群落的哪些特征可以 影响生物降解与掺入。 为了实现这些目标， 提出了以下目标： 1. 评估微生物介导降解与 掺入土壤有机碳基质的多环芳烃（3， 4、5和6环：菲、芘、芘和苯并（a）芘）， 它们的微生物降解产物。 2. 调查多环芳烃及其 降解产物转化为SOM，并深入了解 通过使用13 C-NMR来评估13 C-PAH与SOM的结合机制。 3. 估计降解和融入过程对环境的影响 毒性（用MICROTOX测量）和致突变性（用MUTATOX测量 tm）。 4. 将退化和/或土壤相互作用的速率和程度与 化学物质、土壤和微生物群落的特征。 5. 制定生物补救战略。

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.