Date of Award

Fall 11-14-2025

Document Type

Thesis: Open Access

Degree Name

MS Marine Science

Department

Environmental and Ocean Sciences

Committee Chair

Bethany O'Shea, Ph.D.

Committee Member

Claudia Avila, Ph.D.

Committee Member

Ryan Sinclair, Ph.D.

Committee Member

Suzanné Walther

Abstract

Globally, drylands are expanding, and endorheic basins are in rapid decline. Saline lake desiccation exposes lakebed playa likely to become dust, posing potential health risks to surrounding communities. Studies investigating health risks from playa dust exposure often focus on health effects associated with the presence of airborne particulates, but fewer studies investigate health risks associated with dust source chemistry. This study examines dust source particle composition in a desiccating inland sea in a water-stressed agricultural region of California. Specifically, chemical bioaccessibility of bound trace elements uncovers risks to children, adults, and agricultural worker health. Arsenic exposure via sediment ingestion poses cancer risk values 1-2 orders of magnitude above U.S. EPA cancer risk thresholds for children, adult residents, and outdoor workers, and excess non-cancer risk to children < 6 years old. Arsenic exposure via sediment inhalation poses excess risk to adult residents within the same order of magnitude as the EPA threshold. Cancer and non-cancer calculations for As, Cr, Se, and Cu ingestion and As, Se, and Mn inhalation resulted in risk values below thresholds. Gaps in standardized health risk assessments prevented exploration of chronic Cu, and Pb ingestion and inhalation, and Mn ingestion risks, and eye exposure due to a lack of methods to quantify the risk of metal-dust eye exposure. Due to the likely increases in playa sourced dust associated with endorheic lake desiccation, and the unique health risks posed by lakebed chemistry, investigating health risks associated with desiccating endorheic lakes becomes increasingly important in the context of global public health.

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