Core C: Materials Core

Materials Core提供了表征良好的超级基金相关粒子样本和替代品，旨在测试6个研究项目研究的特定研究假设。构建该核心是为了协助研究与含过渡金属颗粒物（PM）相关的环境持久性自由基（EPFRs）对健康和环境的影响。我们的研究人员发现EPFR是由芳香族氯化苯、氯化苯酚和其他类型的苯酚与金属氧化物的化学吸附形成的，然后是电子转移，减少金属并形成EPFR。这些epfr可以在环境中持续存在并且具有生物活性。在燃烧和热处理系统中浓度较高时，它们还会自反应形成新的污染物，如多氯二苯并-对二恶英和二苯并呋喃。由于细颗粒和超细颗粒具有高的表面体积比，并且由于不满足的价而增加了反应性，因此它们可能特别容易形成EPFR。核心已经开发了设备和技术来合成：i)覆盖单层过渡金属（如氧化铜和氧化铁）的二氧化硅的细颗粒和超细颗粒；Ii)含有相同过渡金属的尺寸可控纳米畴的细小和超细二氧化硅颗粒；Iii)纯铜、铁氧化物的超细颗粒；iv)任何具有相关环境持久性自由基（EPFRs）的这些颗粒；v)适当的对照样本。Core还建立了利用电子顺磁对EPFRs有害物质热处理设备的污染超级基金土壤和颗粒排放的现场样品进行表征的能力

The Materials Core provides samples of well-characterized Superfund-related particles and surrogates designed to test specific research hypotheses for study by the 6 research projects. The Core was constructed to assist in the study of the health and environmental effects of environmentally persistent free radicals (EPFRs) associated with transition metal-containing particulate matter (PM). Our researchers have discovered EPFRs are formed by chemisorption of aromatic chlorinated benzenes, chlorinated phenols, and other types of phenols to metal oxides, followed by electron transfer that reduces the metal and forms the EPFR. These EPFRs can persist in the environment and are biologically active. At high concentrations in combustion and thermal processing systems, they also self-react to form new pollutants such as polychlorinated dibenzo-p-dioxins and dibenzofurans. Because fine particles and ultrafine particles have high surface-to-volume ratios and increased reactivity due to unsatisfied valences, they may be particularly prone to EPFR formation. The Core has developed facilities and techniques to synthesize: i) fine and ultrafine particles of silica coated with a monolayer of transition metals such as copper oxide and iron oxide; ii) fine and ultrafine silica particles containing size-controlled nanodomains of the same transition metals; iii) ultrafine particles of pure copper and iron oxides; iv) any of these particles with associated environmentally persistent free radicals (EPFRs); and v) appropriate control samples. The Core has also established the capabilities to characterize field samples from contaminated Superfund soils and particulate emissions of devices for thermal treatment of hazardous substances for EPFRs using electron paramagnetic resonance (EPR) spectroscopy and molecular precursors using GC-MS and other standard laboratory techniques. The Core has developed systematic approaches for receiving sample requests, establishing chain of custody, and storing particles under vacuum where they will not degrade prior to use. The Core Director has a record of successful collaborations with each of the Project Leaders over the past 5 years, leading to multiple publications.