Date of Award

Fall 2023

Project Type

Thesis

Program or Major

Civil Engineering

Degree Name

Master of Science

First Advisor

Paula J Mouser

Second Advisor

Thomas P Ballestero

Third Advisor

Weiwei Mo

Abstract

Per- and polyfluoroalkyl substances (PFAS) have been used in manufacturing as textile stains, soil repellants, grease proof products, food product coatings, aqueous film forming foams, and more for over 50 years. The carbon-fluorine chain of these compounds is chemically and thermally stable, resistant to biodegradation, and has both hydrophobic and lipophobic properties, making its chemistry unique for many commercial and industrial uses. This research work gathered existing concentration information from New Hampshire’s Environmental Monitoring Database on PFAS in the watershed and discharging to the Great Bay to better frame monitoring locations, temporal trends, and data gaps in the watershed. A mass loading model was developed to determine mass fluxes from surface waters, wastewater treatment plant effluent, groundwater, atmospheric deposition, and Gulf of Maine tides from the lower Piscataqua River to determine major sources of PFAS to the Great Bay. Surface waters were found to contribute over 30% of PFAS mass to the estuary. Carboxylic acid compounds were detected more frequently than sulfonic acid compounds, with PFOA and PFOS detected the most at 76.4% and 72.3%, respectively. This thesis work explores frequency of occurrence through descriptive statistics of the 34 PFAS compounds studied, spatial and temporal trends where available, and a mass loading model highlighting the main sources of PFAS to the Great Bay. These data inform conversations on mass loads to surface waters, including ongoing rulemaking occurring at the state and federal level.

Download

Share

COinS