Louisiana State University and the Health Sciences Centers in New Orleans and Shreveport have formed an interdisciplinary collaboration to perform research on the environmental and health impacts of pollutant-particle systems associated with Superfund sites. Our researchers have discovered chlorinated aromatic hydrocarbons and substituted phenols chemisorb to the surfaces of particulate matter containing redoxactive transition metals where they reduce the metal and form a free radical. These radicals are stabilized by association with surface, and their reactivity is reduced to the point that they can persist in the atmosphere for several days. Our biomedical researchers have shown these environmentally persistent free radicals (EPFRs) associated with ultrafine particulate matter are also persistent in biological media where they initiate long catalytic chain cycles resulting in production of >1000 hydroxyl radicals per EPFR. This promotes oxidative stress leading to induction of pulmonary and cardiac dysfunction as well as altering the expression of P450 enzyme. The EPFRs have been detected in contaminated soils at a Superfund wood-treating site and the fly-ash produced from incineration of hazardous substances. At high concentrations in thermal treatment devices, the EPFRs also promote the formation of new molecular pollutants, such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F). Our center includes 3 non-biomedical projects studying the mechanism of EPFR and PCDD/F formation in thermal treatment systems, formation and fate of EPFRs in Superfund soils, and the properties of fine and ultrafine particles promoting EPFR formation. Three biomedical projects research the effects of EPFRs on oxidative stress-induced cardiac dysfunction, pulmonary dysfunction, and expression of P450. These projects are supported by 3 research cores: a Materials Core to synthesize and characterize particles to test specific research hypotheses, an Oxidative Stress Core to assess generation of ROS and oxidative stress, and a Computational Core to calculate the properties of EPFR-particle systems as a function of particle size. The program also includes, an Administrative Core, Research Translation Core, Community Outreach Core, and Training Core.
Our researchers have discovered what is essentially a new, previously unknown pollutant-environmentally ' persistent free radicals or 'EPFRs'. These radicals appear to be especially prone to form and reside on the surfaces of particulate matter associated with contaminated soils or the thermal treatment of hazardous substances at Superfund sites.
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