Activation, Sensing, and Prevention of Formation of EPFRs in Thermal Treatment of Superfund Wastes

项目概要/摘要：项目4 对包括超级基金场地废物和土壤在内的危险废物进行热处理， 环境持久性自由基（EPFR）与排放的颗粒物（PM）。许多金属 例如PM中存在的铜、铁、锌或镍以不同的产率和不同程度的 稳定性和持久性。这种EPFR实体被证明是导致 在接触人群中观察到心肺健康影响。我们对模型系统的研究， 具有单一金属形态和相关EPFR的颗粒允许在以下方面的显著进步： 了解EPFR的形成机制以及对呼吸和心脏健康的影响 是由EPFR暴露引起的。项目4的中心假设是，EPFR的形成及其 生物活化和它们经历催化循环，产生·OH的倾向由以下定义： PM的成分和介质的理化性质（介质pH值、离子强度和极性） 加速或阻止EPFR激活。项目4探索的主要科学问题包括：1） 环境空气中持久性EPFR在生物系统中转化为非常活跃的氧化还原循环物种，以及2）可以 EPFR的反应性是否可以作为预防或控制EPFR形成及其检测的手段？ 项目4采取系统的方法来解决这些问题，首先通过以下方式界定机制： 所述EPFR从持久自由基转变为产生·OH的反应性物质（即，激活）。一个底部- 在研究中使用了向上方法;从实验室制备的具有简单成分的样品获得的结果 将与更复杂的燃烧产生的EPFR进行比较和评估，最后， 收集EPFR。利用以前的研究结果，我们提出了一种预防EPFR的方法 这将被详细研究。这种方法是基于金属中心的“原位”失活， 热处理（TT）设施，从而有效地阻止EPFR排放。现场传感器的发展是 基于EPFR产生羟基自由基的倾向，并基于可见光吸收， 感官解决方案这些研究的结果将为技术开发提供基础，以控制 在超级基金场地材料的TT期间排放EPFR，并开发简单快速检测装置 和田间EPFR测定。

Project Summary/Abstract: Project 4 Thermal treatment of hazardous waste including Superfund Site wastes and soils leads to the formation of environmentally persistent free radicals (EPFRs) associated with emitted particulate matter (PM). Many metals such as copper, iron, zinc or nickel present in PM form EPFRs with varying yields and different degrees of stabilization and persistency. Such EPFR entities were shown to be potentially a primary factor causing the observed cardiopulmonary health effects in exposed populations. Our studies of model systems containing particles with single metal speciation and associated EPFRs has allowed for significant advancement in understanding the formation mechanism of EPFRs as well as the respiratory and cardiac health effects resulting from EPFR exposure. The central hypothesis of Project 4 is that the formation of EPFRs and their biological activation and their propensity to undergo catalytic cycle, producing •OH, is defined by the constituents of PM and physico-chemical properties of the media (media pH, ionic strength, and polarity) accelerate or prevent EPFR activation. Major scientific questions explored by Project 4 include 1) how does the persistent EPFR in ambient air transform to very active, redox cycling species in biological systems and 2) can the reactivity of EPFRs be exploited as a means to prevent or control EPFR formation and their detection? Project 4 takes a systematic approach to address these questions, starting with defining the mechanism by which EPFRs transition from persistent radicals to reactive species generating ·OH (i.e., activation). A bottom- up approach is used in the studies; results obtained from laboratory-made samples with simple composition will be compared and evaluated against more complex combustion-generated EPFRs and, finally, field- collected EPFRs. Capitalizing on the results from previous studies, we propose a method for EPFR prevention formation that will be studied in detail. This method is based on the “in situ” deactivation of the metal centers in thermal treatment (TT) facilities, thus effectively blocking the EPFR emissions. The field sensor development is based on EPFR propensity to generate hydroxyl radicals and is based on the visible light absorption by sensory solution. The results of these studies will provide a basis for technology development to control the emission of EPFRs during TT of Superfund sites materials and to develop devices for simple and fast detection and measurement of EPFRs in field.