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Characterization of Air Manganese Exposure Estimates for Residents in Two Ohio Towns
Citation:
Colledge, M., J. Wagner, V. Gocheva, C. Beseler, H. Roels, D. Lobdell, AND R. Bowler. Characterization of Air Manganese Exposure Estimates for Residents in Two Ohio Towns. JOURNAL OF AIR & WASTE MANAGEMENT ASSOCIATION CONTROL TECHNOLOGY. Air & Waste Management Association, Pittsburgh, PA, 65(8):948-57, (2015).
Impact/Purpose:
Two Ohio communities were identified with elevated measured concentrations of ambient air-Mn, one of which has the highest concentrations of measured air-Mn reported to the United States Environmental Protection Agency (U.S.EPA) Air Quality System (AQS) database (U.S.EPA, 2012a). Air-Mn in one community (Marietta) is predominantly released from a large ferro-alloy smelting plant (Eramet, Inc.) while in the other community (East Liverpool) it is released during the offloading, grinding (for resizing), packaging, and storage of Mn-containing ore products at a metals storage and packaging facility (S.H. Bell Company. The objective of this study was to estimate inhalation exposures to outdoor air-Mn for residents of two Ohio communities with different emission and source concentration profiles. This modeling will then be used as part of a community health study that was conducted in both communities.
Description:
This study was conducted to derive receptor-specific outdoor exposure concentrations of total suspended particulate (TSP) and respirable (dae ≤1O µm) air manganese (air-Mn) for East Liverpool and Marietta (Ohio) in the absence of facility emissions data, but where long-term air measurements were available. Our "site-surface area emissions method" used U.S. Environmental Protection Agency's (EPA) AERMOD (AMS/EPA Regulatory Model) dispersion model and air measurement data to estimate concentrations for residential receptor sites in the two communities. Modeled concentrations were used to create ratios between receptor points and calibrated using measured data from local air monitoring stations. Estimated outdoor air-Mn concentrations were derived for individual study subjects in both towns. The mean estimated long-term air-Mn exposure levels for total suspended particulate were 0.35 µg/m(3) (geometric mean [GM]) and 0.88 µg/m(3) (arithmetic mean [AM]) in East Liverpool (range: 0.014-6.32 µg/m (3)) and 0.17 µg/3)(GM) and 0.21 µg/m(3) (AM) in Marietta (range: 0.03-1.61 µg/3)).Modeled results compared well with averaged ambient air measurements from local air monitoring stations. Exposure to respirable Mn particulate matter (PM1O; PM <10 µm) was higher in Marietta residents .IMPLICATIONS: Few available studies evaluate long-term health outcomes from inhalational manganese (Mn) exposure in residential populations, due in part to challenges in measuring individual exposures. Local long-term air measurements provide the means to calibrate models used in estimating long-term exposures. Furthermore, this combination of modeling and ambient air sampling can be used to derive receptor-specific exposure estimates even in the absence of source emissions data for use in human health outcome studies
