Collaborative Research: Characterization of Contaminants and Isotopic Tracers Associated with Coal Combustion Products

1235661/1235735徐金/然而合作研究：与煤燃烧产品相关的污染物和同位素示踪剂的表征煤燃烧产品(CCP)是美国最大的工业废物流，每年产生约1.3亿吨。众所周知，这种废物含有砷、硒和汞等有毒元素。虽然一部分CCP被回收用于有益的目的，但大多数废物被储存在全国数百个垃圾填埋场和储存池中。三氯甲烷不被归类为危险废物，因此，这些垃圾填埋场和储存池通常没有衬里，容易发生泄漏和故障。此外，储水池的污水排放往往没有受到监测，如果含有从四氯环己烷中浸出的有毒元素，可能会对生态造成危害。该项目的目标是了解CCP在处置或意外释放到环境中时所造成的危害。这项研究将包括实验室实验，以确定从各种燃煤发电厂采集的CCP的地球化学组成，确定在与环境相关的条件下产生的CCP渗滤液的组成和微量元素形态，并进行现场调查，以表征北卡罗来纳州CCP蓄水池的流出物的特征。这项研究将深入评估从CCP中浸出的金属和类金属污染物，以及它们的形态和生物有效性如何随着环境条件的变化而变化。这项工作的一个新组成部分是使用CCP中的硼、锶和镭的同位素特征作为追踪CCP释放的污染物的方法。煤基能源目前约占全球总发电量的40%，预计未来20年(在美国和全球)将大幅增长。尽管每年产生大量的CCP废物，但与处置做法相关的风险并不为人所知，特别是考虑到最近发生的一次火山灰泄漏事件，在该事件中，PIS确定了与CCP废物有关的有毒元素(砷、硒、汞)的释放。这项研究的结果将是根据火山灰废物造成危害的可能性划分等级，这些等级由原始的煤炭地质和燃烧操作参数等已知变量来描述。这项研究将试图建立已知工艺变量(例如，煤炭类型、煤灰成分、燃烧参数)与CCP中有毒元素的浸出潜力之间的关系。总体而言，CCP淋溶研究和蓄水池分析的结果将被用来评估对CCP的暴露风险潜力进行评级的方法。这些信息将用于联邦和州环境机构未来对CCP处置做法的监管行动。研究人员将利用杜克大学的外展计划以及与公共利益相关者的持续合作，向公众和学生提供这项工作的更广泛传播。

1235661/1235735 Hsu-Kim/HowerCollaborative Research: Characterization of contaminants and isotopic tracers associated with coal combustion productsCoal combustion products (CCPs) represent the largest industrial waste stream in the U.S. with approximately 130 million tons generated every year. This waste is known to contain toxic elements such as arsenic, selenium, and mercury. While a subset of CCPs is recycled for beneficial purposes, the majority of the waste is stored in hundreds of landfills and storage ponds across the nation. CCPs are not classified as hazardous waste, and as a result, these landfills and storage ponds are typically unlined and susceptible to leaks and failures. Moreover, discharge of effluents from storage ponds are often not monitored and may pose an ecological hazard if they contain toxic elements leached from CCPs. The goal of this project is to understand the hazards posed by CCPs during their disposal or accidental release to the environment. The research will involve laboratory experiments to characterize the geochemical composition of CCPs sampled from a wide array of coal-fired power plants, determine the composition and trace element speciation of CCP leachates generated under environmentally-relevant conditions, and perform field investigations to characterize effluent from CCP holding ponds in North Carolina. This research will provide an in-depth evaluation of the metal and metalloid contaminants that can leach from CCPs and how their speciation and bioavailability change as a function of environmental conditions. A novel component of the work is the use of isotopic signatures of boron, strontium, and radium in the CCPs as methods for tracking contaminants released from CCPs. Coal-based energy currently represents approximately 40% of the total worldwide electricity production and is expected to increase significantly in the next 20 years (in the U.S. and globally). Despite the large amount of CCP wastes that are generated annually, the risks associated with disposal practices are not well-known, particularly in light of a recent coal ash spill in which the PIs identified release of toxic elements (arsenic, selenium, mercury) associated with CCP wastes. An outcome of this research will be a hierarchy of coal ash wastes based on their potential to cause harm delineated by known variables such as the original coal geology and combustion operation parameters. The research will attempt to establish relationships between known process variables (e.g., coal type, coal ash composition, combustion parameters) and the leaching potential of toxic elements from CCPs. Collectively the results of CCP leaching studies and holding pond analyses will be used to evaluate methods to rank CCPs for their exposure risk potential. This information will be needed for future regulatory actions on CCP disposal practices from federal and state environmental agencies. The researchers will leverage outreach programs at Duke and on-going collaborations with public interest stakeholders to provide broader dissemination of this work to the public and to students.