Date of Graduation

Spring 5-23-2026

Document Access

Project/Capstone - Global access

Degree Name

Master of Science in Environmental Management (MSEM)

College/School

College of Arts and Sciences

Department/Program

Environmental Management

First Advisor

Allison Luengen

Second Advisor

Amalia Kokkinaki

Abstract

Pesticide pollution in the California Central Valley (CV) is a major concern for aquatic toxicity. This research will determine if photocatalytic advanced oxidation processes (AOP), an emerging water treatment technology, could be implemented within the CV to degrade pesticides. A case study, literature review, comparative analysis, and policy analysis were conducted to identify pesticides of concern within the CV, if photocatalytic AOP can degrade those pesticides, how photocatalytic AOP compares to current technologies, and regulatory challenges with implementing photocatalytic AOP. Between 2019 and 2023, the top 30 most applied pesticides were identified, with 12 chemicals identified as aquatic toxicants, seven of which were present in CV surface waters (chlorothalonil, glufosinate ammonium, glyphosate, methoxyfenozide, oxyfluoren, paraquat dichloride, and pendimethalin). Photocatalytic AOP was found to be effective in degrading all seven pesticides in laboratory and pilot studies with a percent removal efficiencies range of 81-100%. The most efficient catalyst to consider is a co-doped titanium oxide catalyst with magnetic properties to increase catalyst recovery for reuse, as well as increase sunlight degradation efficiency. This is a cost effective, sustainable, and efficient system that could reduce pesticides in surface waters and protect aquatic ecosystems. While constructed wetlands and vegetative filter strips are best practices, these systems have inconsistent degradation rates (10-100%). A hybrid pilot program would be instrumental in determining the effectiveness of photocatalytic AOP within the CV. This technology has not been studied in the California agricultural industry. A pilot program is necessary as results vary within different effluent characteristic, catalyst loads, water flow, and sunlight availability.

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