Date of Award

4-2026

Document Type

Thesis

Degree Name

Master of Public Health

Department

Health Science and Human Ecology

First Reader/Committee Chair

Becky Talyn

Abstract

Background: Glyphosate, the nominal active ingredient in professional-grade Roundup weed and grass killer, is the most extensively used herbicide globally and in the United States (U.S. Environmental Protection Agency, 2020). An increasing level of concern has surfaced regarding its health consequences, particularly because of contamination of our food supplies. Recent research indicates distressing levels of detection of glyphosate in human blood and urine samples, revealing many instances of frequent human exposure (Conrad et al., 2017; Zhang et al., 2020).Most of the research about exposure is focused on agricultural workers or individuals living in close vicinity to agricultural lands.  Few studies have evaluated how dietary behaviors, socioeconomic status, and demographics combine to influence glyphosate exposure. This study aimed at quantifying levels of glyphosate residue in urine samples of the diverse population of students from a Southern California public university system with two campuses, located in Urban and Para agricultural. Moreover, it examines the relationship between glyphosate exposure and social justice factors, including city of residence, socioeconomic status, and both occupational and dietary exposure risk factors.

Methods: This study utilizes qualitative and quantitative research methods to detect urinary glyphosate concentration in a university-based cohort. Students, faculty, and staff provided urine samples and completed post-collection surveys. Participants answered questions to gauge their knowledge and attitudes towards organic foods. Other questions assessed socioeconomic and demographic factors. Urinary glyphosate concentration was measured by using an ELISA assay as a measure of herbicide exposure. Data was analyzed using the Statistical Package for Social Sciences (SPSS) software version 31.0(117). The dietary, socioeconomic, and demographic data were compared with the urinary glyphosate values, comparing students from an urban campus and a suburban campus within an agricultural area. Additionally, this study evaluates differences between students and employees from both campuses.

Results: The glyphosate concentrations and post-sample-collection survey were analyzed to identify associations between dietary habits, socioeconomics, and demographics to the urinary glyphosate concentrations. Across the whole cohort, the mean level of glyphosate in samples was 1.91 ± 0.43 µg/L. Higher glyphosate exposure was detected in urine of cis-gendered females compared to cis-gendered males. Students at the urban campus had higher concentrations of glyphosate in urine in contrast to students at the suburban/para-agricultural campus. Further, the study compared socioeconomic factors like residence location and annual household income to urinary glyphosate levels and found no significant association. Additionally, no association was seen between dietary habits and glyphosate concentrations.

Conclusion: In general, populations are exposed to glyphosate-based herbicides regularly through various unidentified pathways, speculated to be common dietary sources or environmental exposures such as herbicide use during landscaping. This study contributes to understanding glyphosate exposure in a non-occupational setting such as a university population, rather than agricultural workers. Universities can initiate awareness programs for cis gendered females as they exhibited higher concentration, organic food intervention to provide information about healthy grocery shopping websites and pesticide contaminated food lists, and quick facts about glyphosate exposure and its risks to the human body. Moreover, future research should be conducted for a more diverse and larger non-agricultural population, as well as comparing agricultural workers and groundskeepers with a general population.

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