Sequestration Mechanisms and Bioavailability of Tetrachloroethene and Toluene in Solid Waste

这项研究的目的是研究控制垃圾填埋场中四氯乙烯（PCE）和甲苯的命运和生物利用度的因素，特别关注固体基质中腐殖质物质的存在以及产酸和产甲烷的渗滤液对污染物的隔离和生物降解的影响。具体目标是：(1)通过测量新鲜和生物降解形式的主要有机废物组分的吸附能力来估计固体废物中吸附污染物的分布；(2)确定垃圾渗滤液中溶解的有机大分子对污染物的结合是否会减少污染物的吸附；(3)确定老化和渗滤液成分对污染物解吸率的影响。(4)确定分解吸附剂基质的化学和物理变化与PCE和甲苯的生物利用度和固存之间的关系；(5)比较新鲜污染物和老化污染物的解吸和生物降解率，以确定解吸是否限制了生物利用度；(6)确定与腐殖质材料的共价和/或非共价结合对固体废物中PCE和甲苯的固存是否重要。这项研究将提供关于污染物在长时间内如何在垃圾填埋场中表现的信息，并将支持开发预测垃圾填埋场污染物命运的模型。* * *

0001700 Barlaz The objective of this research is to study factors that control the fate and bioavailability of tetrachloroethene (PCE) and toluene in landfills with a specific focus on contaminant sequestration and biodegradation as influenced by the presence of humic substances in solid matrices, and acidogenic and methanogenic leachate. The specific objectives are to: (1) estimate the distribution of sorbed contaminants in solid waste by measuring the sorptive capacity of the dominant organic waste components in both fresh and biodegraded form, (2) determine whether contaminant sorption is reduced as a result of contaminant binding by dissolved organic macromolecules in landfill leachate, (3) determine the impacts of aging and leachate composition on contaminant desorption rates, (4) identify relationships between chemical and physical changes in the decomposing sorbent matrix and the bioavailability and sequestration of PCE and toluene, (5) compare rates of desorption and biodegradation of fresh and aged contaminants to determine whether desorption limits bioavailability, and (6) identify whether covalent and/or noncovalent associations with humic materials are important for the sequestration of PCE and toluene in the solid waste. This research will provide information on how contaminants may be expected to behave in landfills over long periods of time and will support the development of models to predict contaminant fate in landfills. ***