Watershed Symposium 2022

With Great Salt Lake dessication, Northern Utahns have expressed worry about the effects of dust storms on air quality and health. We present dust flux and geochemistry data for the Salt Lake Valley, and investigate possible sources of specific metals within dust, as well as the current limitations of environmental health evaluations of dust.

The Salt Lake Valley, UT, USA, home to more than 2 million people, is situated proximal to the drying Great Salt Lake and to the east of other dry playas. Prior work has found that these playas contribute dust to snowpack in the Wasatch and Uinta Mountains to the east of the cities, and that dust contain high relative abundances of trace metals like Pb and Cu. However, no prior study has characterized the contributions of geogenic dust and industrial particulate pollution to communities along the Wasatch Front. In this study, we analyzed the dust deposited in 18 passive samplers positioned near the Great Salt Lake, Ogden, Bountiful, the Salt Lake Valley, and Lehi for total dust flux, the < 63 μm dust fraction, 87Sr/86Sr, and trace element geochemistry. We observed the highest dust fluxes at wealthy exurban sites near the western boundary of the urban area. Within the urban corridor, strontium isotope ratios and the spatial distribution of trace elements suggested that Great Salt Lake playa dust contributes only a small amount of material to dust in urban areas. Instead, based on the < 63 μm dust fraction, our results suggest the contributions of local soil disturbance. In our data, many trace metals exceed EPA Regional Screening Levels for soil (As, Co, Cu, La, Li, Mn, Ni, Tl, and U) and exhibited enrichments relative to both upper continental crust and playa dust collections. This suggested the direct contribution of particulate pollution via industries like Cu mining, concentrating and smelting, and oil refining, as well as historical pesticide and herbicide applications. Bulk ‘priority pollutant’ relative abundances did not track income, race or ethnicity demographics. However, certain elements (As, V) indicated a statistically significant positive correlation with income, whereas Pb, Tl and Ni indicate enrichment in the least wealthy and least white neighborhoods. Findings from this study suggest the importance of understanding constituent-specific loadings from particulate matter and dust in urban areas influenced by industry.