USING ELECTRON MICROSCOPY AND ISOTOPE GEOCHEMISTRY TO ASSESS PARTICULATE POLLUTION IN STREET SEDIMENT NEAR A COAL-FIRED POWER PLANT IN HAMILTON, OHIO

In urban environments, heavy metals derived from coal-fired power plants and many other sources are a significant component of particulate pollution. Because particulate pollution can significantly impact communities, identification of sources and potential remediation strategies are critical. Publically accessible street sediment offers a means of assessing the extent and nature of pollution in urban environments. Street sediment was collected in Hamilton, Ohio near a coal-fired power plant to determine if coal-derived pollution was present and, if so, whether the pollution poses a risk to human health and the general environment (e.g. stormwater runoff). Electron microscopy indicates several sources of heavy metals based on particulate composition and morphology. Some heavy metals occur as discrete submicrometer particles and some are sorbed onto clay particles. Sources likely include the adjacent coal-fired power plant, nearby industrial facilities, automobiles, and road paint, among others. Isotope geochemistry can differentiate coal pollution from other potential pollution sources. Current Pb isotope data suggest that Pb is derived largely from road paint, while other metals may be derived from multiple sources including the coal-fired power plant. Electron microscopy indicates that road paint samples contain abundant lead chromate with an average particle size of approximately 200 nm. Combined electron microscopy and isotope geochemistry investigations may serve as a means for recognizing potential public health risks that may be related to street sediment in urban communities. Currently, respirable heavy metal particulates are often unaccounted for in community health assessment. Routine street sweeping, improved particulate capture technology at the power plant, and stormwater filter and capture systems are some corrective actions to reduce exposure to particulate pollution. Approaches used in this investigation are easily translatable to other urban settings with complex sources of particulate pollution.