Chemical exposures in drinking water: contaminant analysis and physicochemical behavior

Abstract

Environmental chemical exposures pose an understudied risk to human health. The quality and accessibility of data on occurrence in the environment and physicochemical behavior of industrial chemicals are integral for accurate exposure risk assessment. In this dissertation, analytical chemistry techniques were developed and leveraged to characterize human exposures to contaminants in drinking water and improve methods for assessing such risks. The occurrence of organic industrial pollutants in domestic well waters was investigated, with a particular focus on the impacts of region-specific industrial activity (e.g., hydraulic fracturing), legacy pollution sites (e.g., Superfund sites), and geochemistry. The exposure risk to water contaminants of domestic well users was further interrogated by evaluating trends in contaminant concentrations resulting from the implementation and maintenance of in-home water treatment devices. The results show widespread, low-dose mixtures of organic pollutants, where the efficacy of removal by in-home water treatment varied by water contaminant class and maintenance frequency. Additionally, analytical methods were optimized to quantify a group of organic water contaminants (i.e., probable carcinogens, N-nitrosamines), improving method sensitivity and critically identifying false-positive interferences. Finally, methods were evaluated and deployed for the determination of physicochemical properties of N-nitrosamines. The results of which demonstrate gaps in existing experimental data, provide a valuable methodological intercomparison (two experimental and two computational approaches), and contribute novel partitioning data. This dissertation addresses gaps in occurrence data, analytical method sensitivity, and reliability of physicochemical parameters for risk assessment. The combination of method development and implementation enables the study of exposures to water contaminant mixtures at health-relevant concentrations, representative of prevalent exposure pathways.