Date of Graduation
5-2026
Document Type
Thesis
Degree Name
Bachelor of Science in Agricultural, Food and Life Sciences
Degree Level
Undergraduate
Department
Crop, Soil and Environmental Sciences
Advisor/Mentor
Muenich, Rebecca
Committee Member
Rudko, Noah
Second Committee Member
Brye, Kristofor
Third Committee Member
Haggard, Brian
Fourth Committee Member
Speir, Shannon
Abstract
Per- and polyfluoroalkyl substances (PFAS), commonly referred to as “forever chemicals,” are complex chemical compounds consisting of a carbon chain where the hydrogen ions are fully or partially replaced by fluorine ions. The amphiphilic properties of these “forever chemicals” make the compounds resistant to chemical and thermal breakdown. PFAS are present in a variety of products, and are used in aqueous film-forming foam, which contributes to elevated PFAS concentrations in surface waters adjacent to airports or military bases. Traditional sampling methods for PFAS in surface water consist of a grab-sample below the water surface, which could be underestimating PFAS concentrations due to the compound’s amphiphilic properties. Therefore, the objective of this study was to determine whether traditional sampling techniques underestimate PFAS concentrations by sampling both at and below the water surface. Two study sites were selected in proximity to a suspected PFAS source, samples were collected weekly, and quantified using United States Environmental Protection Agency (EPA) method 1633. PFAS concentrations had numerically greater means and medians at the surface compared to samples collected from middle of the water column. The findings support that traditional sampling techniques can underestimate PFAS concentrations by only sampling below the water surface. All 13 PFAS compounds were determined to have numerically greater averages at the surface compared to the middle at both sampling sites. Sample location (i.e., upstream and downstream) significantly affected (p ≤ 0.05) six PFAS compounds including perfluorobutanoic acid (PFBA), perfluorodecanoic acid (PFDA), perfluoroheptanoic acid (PFHpA), perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), and perfluorobutane sulfonamide (FBSA). Sample depth (i.e., surface and middle) significantly affected (p ≤ 0.05) four PFAS compounds including perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorooctane sulfonate (PFOS), and 6:2 fluorotelomer sulfonate (6:2 FTS). By understanding PFAS concentrations can vary based on sampling depth, state and national organizations can properly guide sampling requirements and set appropriate maximum PFAS concentrations.
Keywords
PFAS; PFOA; PFOS; Environment; Water
Citation
Villeneuve, A. E., Logsdon, R., & Rudko, N. (2026). Quantifying the Impacts of Sampling Methods on Per- and Polyfluoroalkyl Substance Contamination Estimates in Urban Surface Waters in the Ozark Highlands. Crop, Soil and Environmental Sciences Undergraduate Honors Theses Retrieved from https://scholarworks.uark.edu/csesuht/56
