37-3 Arsenic on the Playa: Spatial Mapping and Geochemical Comparison of Exposed Great Salt Lakebed Sediment

Session: Geoscience Research Poster Showcase by 2YC and 4YCU Undergraduate Students

Poster Booth No.: 126

Presenting Author:

Naomi Kelly

Authors:

Kelly, Naomi M.¹, Miller, Lindy V.², Sorensen, Mary ³, LeMonte, Joshua J.⁴

(1) Department of Geological Sciences, Brigam Young University, Provo, Utah, USA, (2) Department of Geological Sciences, Brigam Young University, Provo, UT, USA, (3) , (4) Department of Geological Sciences, Brigham Young University, Provo, UT, USA,

Abstract:

The Great Salt Lake has been steadily shrinking, exposing over 750 square miles of lakebed sediment referred to as the playa (Perry et al.). Prevailing wind patterns have been tracked blowing the top layer of this sediment towards the populated Wasatch Front. This has become a major public health concern in the area as it has been found that lakebed sediment and subsequent dust contain heavy metals including As (Perry et al.). Due to the high stakes and high interface with the local population, a deeper understanding of the geochemical makeup and interactions across the lake is needed. While it is known that there is As in the sediment, the more bioavailable and reduced form As(III) is of more concern than the oxidized form As(V) because it is more easily absorbed by the body. Having a better understanding of how As interacts spatially and what other elements is the next step to being able to address these concerns.  

To do this, we will be creating geochemical maps of the spatial distribution and correlation matrixes of other elements. We sampled 30 sites across the lake taking 10cm and 2 ft cores. Sites were reached using fat tire bikes allowing us to get a comprehensive view of the whole playa not just isolated regions. Samples were immediately vacuumed-sealed in the field and then processed in an anaerobic glove box to preserve conditions. Following acid digestion and dilution, inductively coupled plasma (ICP-OES) analysis was used to determine total chemical breakdown. 

Results from the top 1cm revealed that on average the total As is 10 times higher than EPA industrial standards of 3ppm (U.S. EPA, 2024). Geochemical data will be mapped and put into a comparison matrix to identify hotspots and areas of concern and better understand possible speciation by looking at chemical colocation. This data will ultimately allow stakeholders and policy makers in the area to create targeted interventions for the region involving Great Salt Lake dust and subsequent water management. 

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