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.

受污染的地下水是接触有毒物质的最重要途径。 对于许多依赖威尔斯饮用水的人来说， 和其他家庭用途。 地下水含水层极易受到 由于污染物从超级基金和其他 危险废物场。 不幸的是，很难预测 地下水含水层污染的可能性和 污染物从危险废物场向地下水的移动。 的 非饱和地下（渗流）环境是非常不均匀的， 它的物理、化学和生物过程还没有得到应有的重视。 这类过程对饱和地下水含水层的影响值得注意。 的 将渗流区的局部过程按比例扩大到 系统规模阻碍了预测模型的发展， 对于描述地下输运和评估潜在的 暴露于人群。 挥发性有机化学品（VOC），如三氯乙烯、甲苯和 萘是地下水中普遍存在的常见污染物。 所有 三种化学物质是环保署的优先污染物，并有可能成为 在环境中转化为不需要的代谢物， 对人类健康的危害。 将进行研究，调查基本过程- 包括扩散和对流传输、吸附/解吸，以及 生物降解-影响土壤中挥发性有机化合物的归宿和运输， 地质沉积物 生物降解的速度将与 人口规模和土著人的酶和遗传特性 污染和未污染包气带微生物群落 样品 形成VOC有毒代谢物的可能性 将在各种条件下测定它们的生物降解过程。 将使用土壤和 地质沉积物以确定多种环境的影响 挥发性有机化合物浓度和挥发性有机化合物移动到 地下水和大气。 VOC传输之间的关系 渗流带的过程和现场规模的地质属性，如 沉积相、粒度、有机碳、分选和矿物学 将被确定。 对这些关系的定量描述将 纳入运输的确定性和随机性模型， 包气带 这些模型将使用来自受污染的 地点在劳伦斯利弗莫尔国家实验室，以确定灵敏度 挥发性有机化合物的迁移率和气相及液相浓度， 它们的代谢物的空间变异性的运输特点。