UC Irvine

The prevalent utilization of glyphosate-based herbicides in modern landscaping and agricultural practices necessitates a methodical exploration into the monitoring, forecasting, and assessment of glyphosate's ubiquity and its consequential impacts. The goal of this research was to develop tools for better understanding of the fate, transport, and public health implications of glyphosate, glufosinate and aminomethylphosphonic acid (AMPA) in environmental matrices. The work resulted in the development of robust analytical detection tools for the monitoring of glyphosate-based herbicides in tap, surface, and groundwater sources. Developed method overcame analytic limitations by utilizing 9 fluorenylmethylchloroformate (FMOC-Cl) pre-column derivatization and solid phase extraction (SPE) via liquid chromatography with tandem mass spectrometry (LC-MS/MS) to achieve detection limits lower than World Health Organization (WHO) standards. The spatiotemporal transport and distribution of the target compounds and the vulnerability of various watersheds were investigated via remote sensing (RS) and groundwater interconnectivity models. The trends identified showed varying levels of watershed pesticide vulnerability across the study areas in Kentucky, USA, and Belize, indicating shifts in sensitivity of the model to environmental and public health influences, with emphasis on karst and alluvial geological settings as higher-risk areas, underscoring the importance of adopting responsible pesticide application methods for achieving sustainable agricultural practices and water source protection. Results from the prediction models and experimental field monitoring data were analyzed and correlated with socio-economic and environmental justice factors to establish a comprehensive understanding of the intricate interplay between agricultural practices, environmental impact, and societal equity. The study reveals a significant portion of groundwater vulnerability to glyphosate contamination is concentrated in densely populated regions due to reliance on aquifer reserves for drinking water. There also exist a disproportionate impact on low-income and Black, Indigenous, and People of Color (BIPOC) communities highlighting the need for equitable planning and sustainable development practices to address environmental disparities and ensure community well-being.