Honors Theses and Capstones

Date of Award

Spring 2023

Project Type

Senior Honors Thesis

College or School

CEPS

Department

Civil & Environmental Engineering

Program or Major

Earth Sciences

Degree Name

Bachelor of Science

First Advisor

Paula J. Mouser

Abstract

Per- and polyfluoroalkyl substances (PFAS) are a group of over 4,000 compounds used in the manufacturing of products including aqueous film forming foams for firefighting, stain repellents, waterproofing agents, and nonstick cookware since their initial development in the 1940s. The long fluorinated carbon chain structure of PFAS causes chemical and thermal stability, and thus resistance to biodegradation. Biosolids produced at wastewater facilities for uses such as agricultural land-applied compost and fertilizer for lawns and athletic fields, as well as sludge disposed in landfills can cause contamination of groundwater and surface water. This poses a significant threat to human and environmental health. This research looks at presence and concentration of various PFAS in biosolids samples collected by the New Hampshire Department of Environmental Services (NHDES) from 2019 to 2022. An additional focus is placed on five of the six PFAS targeted by the U.S. Environmental Protection Agency’s recent proposed updated national drinking water standards for PFAS (PFOA, PFOS, PFNA, PFBS, and PFHxS). All biosolids samples were split into eight groups based on production method. Statistical analysis was conducted using the software JMP Pro version 16 to determine (1) if presence of specific PFAS at levels above each sample’s respective reporting limit is independent of the specific PFAS and (2) if there is a difference in central tendency of concentration of each PFAS between each processing group. This research will help inform NHDES of trends in PFAS presence and concentration in biosolids, which may cause facilities to reexamine their processing methods.

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