TRANSPORT AND BIODEGRADATION OF VOLATILE ORGANIC COMPOUNDS IN THE VADOSE ZONE

渗气区挥发性有机化合物的迁移和生物降解

• 批准号: 3755087
• 负责人: DENNIS E ROLSTON
• 金额: --
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3755087
• 关键词: DNA damage; acidity /alkalinity; adsorption; analytical chemistry; biotransformation; carbopolycyclic compound; diffusion; environmental contamination; environmental toxicology; environmental transport; halocarbon compound; industrial waste; microorganism population study; naphthalenes; organic chemicals; polymerase chain reaction; soil microbiology; soil pollution; toluene; trichloroethylene; vapor

Polluted groundwater is the most significant route of exposure to toxic chemicals for many human populations who rely on wells for drinking water and other domestic use. Groundwater aquifers are extremely vulnerable to contamination due to migration of pollutants from Superfund and other hazardous waste sites. Unfortunately, it is very difficult to predict the potential for contamination of a groundwater aquifer and the rate of movement of pollutants from hazardous waste sites to the water table. The unsaturated subsurface (vadose) environment is extremely heterogeneous and its physical, chemical, and biological processes have not received the attention that such processes have in saturated, groundwater aquifers. The uncertainties in scaling up local processes in the vadose zone to the system scale impedes the development of the predictive models that are essential for describing subsurface transport and assessing the potential exposure of human populations. Volatile organic chemicals (VOCs), such as trichloroethylene, toluene, and naphthalene, are ubiquitous and common contaminants of groundwater. All three chemicals are E.P.A. priority pollutants and have the potential to be transformed in the environment into undesirable metabolites that pose a health risk to human populations. Studies will be conducted to investigate the fundamental processes-- including diffusive and convective transport, sorption/desorption, and biodegradation--affecting the fate and transport of VOCs in soil and geological sediments. Rates of biodegradation will be related to population size and the enzymatic and genetic properties of indigenous microbial communities in contaminated and uncontaminated vadose zone samples. The potential for formation of toxic metabolites of the VOCs during their biodegradation will be determined under various conditions. Laboratory-scale, column studies will be conducted using soil and geological sediments to determine the effect of multiple environmental processes on VOC concentrations and the potential for movement of VOCs to the groundwater and atmosphere. Relationships between VOC transport processes and field-scale geological attributes of the vadose zone such as depositional facies, grain size, organic carbon, sorting and mineralogy will be determined. Quantitative descriptions of these relationships will be incorporated into deterministic and stochastic models of transport in the vadose zone. These models will be run with data from a contaminated site at Lawrence Livermore National Laboratory to determine the sensitivity of migration rates and vapor and solution phase concentrations of VOCs and their metabolites to spatial variability in transport characteristics.

污染的地下水是最重要的暴露途径 许多依靠井的人口的化学品用于饮用水 和其他家庭用途。 地下水含水层非常容易受到伤害 由于超级基金和其他污染物的迁移而引起的污染 危险废物站点。 不幸的是，很难预测 地下水含水层污染的潜力和 污染物从危险废物站点转移到地下水位。 这 不饱和地下（vadose）环境非常异构，并且 它的物理，化学和生物过程尚未收到 注意此类过程在饱和的地下水含水层中存在。 这 不确定性扩展vadose区域的本地过程到 系统规模阻碍了预测模型的发展 描述地下运输和评估潜力至关重要 人口的暴露。 挥发性有机化学（VOC），例如三氯乙烯，甲苯和甲苯和 萘，无处不在的地下水污染物。 全部 三种化学物质是E.P.A.优先污染物，有可能 在环境中转变为不良代谢物，构成a 人口的健康风险。 将进行研究以调查基本过程 - 包括扩散和对流的运输，吸附/解吸以及 生物降解 - 影响土壤中VOC的命运和运输 地质沉积物。 生物降解率将与 种群大小以及土著的酶促和遗传特性 在受污染和未污染的vadose区域中的微生物群落 样品。 形成VOC的有毒代谢产物的潜力 在其生物降解期间将在各种条件下确定。 实验室规模，专栏研究将使用土壤和 地质沉积物以确定多个环境的影响 VOC浓度的过程以及VOC移动的潜力 地下水和气氛。 VOC运输之间的关系 vadose区的过程和现场尺度地质属性，例如 沉积相，晶粒尺寸，有机碳，分类和矿物学 将确定。 这些关系的定量描述将 被纳入确定性和随机传输模型中 vadose区。 这些模型将通过受污染的数据运行 劳伦斯·利弗莫尔国家实验室的地点以确定灵敏度 迁移率，蒸气和溶液阶段浓度的VOC和 它们的代谢物是运输特征的空间变异性。