Date of Award

January 2024

Document Type

Open Access Thesis

Degree Name

Master of Public Health (MPH)

Department

School of Public Health

First Advisor

Nicole Deziel

Abstract

Thousands of federally unregulated ‘emerging’ contaminants are entering and persisting in our environment, potentially adversely impacting public health. Drinking water is a major exposure pathway for some of these emerging contaminants. In 2020, New York State set maximum contaminant level (MCL) drinking water standards for three emerging contaminants: 1,4-dioxane: 1 ppb, perfluorooctanoic acid (PFOA): 10 ppt, and perfluorooctanesulfonic acid (PFOS): 10 ppt. Databases of public drinking water exist but generally do not contain comprehensive and ancillary data reported by annual public drinking water reports, or the data may not be aggregated or readily available in a format suitable for data analysis. Aggregated, ancillary data is relevant for evaluating the impact of MCL policies and the potential for exposure and health impacts associated with drinking water contamination.The objectives of this study were to construct a database of emerging contaminants in public drinking water in Nassau County, New York, to evaluate trends in 1,4-dioxane, PFOA, and PFOS levels sampled before and after the MCL was implemented, and to explore the relationship between water district characteristics and concentration levels. A total of 157 decentralized annual water quality reports published between 2016 and 2022 from 35 separate water systems in Nassau County were compiled into a centralized database and analyzed, with information on water system characteristics and sampling concentrations of emerging contaminants. Annual water quality reports were obtained as PDFs from water district web pages. A descriptive analysis was completed to count the total number of samples exceeding 2020 MCLs and not exceeding 2020 MCLs by water system size, aquifer source, deferral received (yes/no), advanced treatment (some/none), and violations received. Analyses of our database found that before the policy was implemented, 66% of 1,4-dioxane, 21% of PFOA, and 29% of PFOS samples exceeded the MCL. After the policy was implemented, 35% of 1,4-dioxane, 8% of PFOA, and 12% of PFOS samples exceeded the MCL. Despite exceedances post-policy, no water system reported a violation; however, several reported receiving deferrals, with 31% of water utilities receiving a deferral after the policy was implemented. When comparing samples that exceeded MCL levels, a significant difference was found in 1,4-dioxane levels measured before and after the MCL was implemented (p=0.002), with levels declining over time. Several discrepancies in reporting sample concentrations and water system characteristics across different reports and water systems complicated analysis, such as inconsistent sample date and treatment reporting. This study produced a newly developed dataset with detailed information on sampling data of emerging contaminants and associated water system characteristics such as deferral status, treatment, system size, water cost, and water source. This dataset could be used to conduct additional analyses of the relationship between concentrations of emerging contaminants and water district characteristics and to inform water quality policy. This analysis found that concentrations of 1,4-dioxane are declining in Nassau County, NY.

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This is an Open Access Thesis.

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