10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Impact of a Shrinking Saline Lake (Salton Sea) on Regional Dust Deposition and Composition
ALEXANDER FRIE, Alexis Garrison, Mia Maltz, Jon Botthoff, Steve Bates, Timothy Lyons, Emma Aronson, Roya Bahreini, University of California Riverside
Abstract Number: 1437 Working Group: Source Apportionment
Abstract Shrinking saline lakes and the formation of large emissive lake beds (playas) are increasingly common as demand for water resources in arid regions grow. The Salton Sea (SS) is a saline lake with water levels receding, exposing the playa underneath. The resulting playa exposures are raising air quality concerns in the SS air basin. SS Playa dust emissions are compositionally distinct from other regional particulate matter (PM) sources and typical mineral dust, allowing for tracing of playa emissions. Previous work has identified SS playa influences on ambient PM10 on short time scales, attributing ~10% of PM10 mass and >40% of PM10 Na to playa sources.1 To quantify the impact of SS playa emissions on PM mass and composition on longer timescales and with greater spatial resolution, monthly depositional samples are collected from five sites in the SS Basin and Coachella Valley from May 2017-2018. The total elemental and soluble anion concentrations within these samples are respectively measured with inductively-coupled plasma mass spectrometry (ICP-MS) and ion chromatography. These data will be input into Positive Matrix Factorization (PMF) software to isolate source contributions and determine source profiles of the deposited dust. Additionally, enrichment factors are calculated and used to explore compositional differences in depositing dust at each site, including those driven by playa exposures. Preliminary results show samples from sites closest to the SS playa surfaces have high enrichments of sulfate, Na, Ca, and Se, indicating compositional changes driven by playa emissions. These data provide insight into the regional importance of SS playa emissions and their effect on PM composition.
References [1] The Effect of a Receding Saline Lake (The Salton Sea) on Airborne Particulate Matter Composition Alexander L. Frie, Justin H. Dingle, Samantha C. Ying, and Roya Bahreini. Environmental Science & Technology 2017 51 (15), 8283-8292 DOI: 10.1021/acs.est.7b01773.