In semiarid environments such as the Southwestern US, mining operations, including crushing, grinding, smelting, refining, and tailings management, are an important source of airborne metal and metalloid contaminants. Spent ore from mining operations is accumulated in mine tailing deposits, which are typically open to the atmosphere and thus susceptible to wind erosion. Dust particles emitted from mine tailings mobilize trace metals, which can then accumulate in soils, natural waters and vegetation. Furthermore, smelting operations release metals in the form of fume and fine particulate matter that disperses more readily than coarser soil dusts. Ancillary smelting activities and wastes may also contaminate local soils, which can then be dispersed by wind erosion. Human exposure to the dust can occur through inhalation and, especially in the case of children, incidental dust ingestion. Characterization of airborne dust in regions influenced by mining activity can provide information about sources, fate and transport, and the potential for human exposures.
At the University of Arizona, Drs. Betterton and Sáez are performing size-resolved chemical characterization of atmospheric aerosols near mining sites in Arizona. By determining the chemical components of mine tailings dust as a function of particle diameter, their research will generate source apportionment data, improve fate and transport models of airborne particulates, and better assess potential health impacts of contaminated dust.
Warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, with potential deleterious effects on human health and ecology. These studies will provide insights into the source and fate and transport of metal-contaminated airborne particulates, with implications for human exposure.
Specific Aim 1: To quantify dust emissions from mining sites including assessment of dust flux and particle size distribution.
Specific Aim 2: To assess the relationship between outdoor contaminated dust and indoor exposure.
Specific Aim 4: To perform a comprehensive analysis of source apportionment of contaminants in dust and aerosol in a smelter site (Hayden-Winkelman).