ELECTRON MICROSCOPY INVESTIGATION OF STREET SEDIMENT REVEALS COMPLEXITIES OF COAL POLLUTION IN HAMILTON, OH: CAUSE FOR HEALTH CONCERNS

Hamilton is an economically disadvantaged city in southwest Ohio with numerous environmental issues related to manufacturing and industry. A community of 53 homes in Hamilton lies between the Great Miami River and the coal-burning Hamilton Municipal Electric Plant. Street sediment samples were investigated in the small community of homes and adjacent areas to assess if appreciable concentrations of priority pollutant metals exist near the coal plant.

ICP-MS analysis shows street sediment from the community of homes adjacent to the coal plant and surrounding areas contains significantly elevated concentrations of Cr, Cu, Ni, Pb, and Zn, however Hg in all samples is below detection. Microscopy investigations clearly identify components of coal-derived pollution in the sediment samples and place textural, geochemical, and mineralogical constraints on the nature of the waste. Scanning electron microscopy (SEM) indicates spherical aluminosilicate fly ash particles approximately 50 to 100 μm in diameter are abundant in street sediment samples. Fly ash particles vary widely in size and texture and are similar to those identified in previous coal pollution studies. SEM indicates that heavy metals occur as discrete submicrometer particles and that barite is abundant in some samples. Submicrometer tungsten particles also occur in street sediment samples and likely originate from the coal plant, as stacks are often lined with W-containing steels. Transmission electron microscopy (TEM) indicates that several clay minerals are present and that heavy metal pollutants occur at detectable concentrations in aggregates of phyllosilicates and Fe-oxide coatings.

Fly ash and heavy metals in the street sediment indicate a probable common origin from the coal plant. Microscopy results indicate some heavy metal pollutants are respirable and may be a health hazard. TEM investigation suggests complex processes of mobilization and sorption occur, which likely impact the quality of storm water generated in the area. Other potential impacts include bioaccumulation and economic effects such as decreased home value. This study raises concern for the health and well being of the Hamilton population overall and illustrates the mineralogical and geochemical complexity of an ongoing problem.