Abstract

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals that are of emerging concern in the environment. PFAS are known to bioaccumulate, thus their monitoring levels in aquatic organisms is needed. Measurement of PFAS in organisms, such as fish, to assess biological impacts can be challenging. Here, a biomimetic passive sampler to assess bioconcentration factors (BCF) of PFAS in fish was developed and tested. The sampler was based on swellable organically modified silica (SOMS) comprised of 250 mg/g of adsorbed bovine serum albumin (BSA). BSA was chosen as the protein of the passive sampler because serum albumin is abundant in the blood of many organisms and has been hypothesized to be the main carrier of PFAS.

Laboratory testing of the BSA-SOMS passive sampler was conducted. Measurement of PFAS adsorption over time indicated that the passive samplers reached fast equilibrium (within the first three days of deployment). Results from laboratory testing show an increasing KSW (sampler-water equilibrium constant) of PFAS by chain length. Binding affinity for individual PFAS to BSA-SOMS passive samplers increased for PFAS with longer fluorinated carbon chains. Increased binding affinity with longer chain lengths matches trends in fish tissue bioconcentration factors for PFAS. The BSA-SOMS passive sampler was tested in natural waters during field testing in Ghana. Sampling took place in the Volta River, the main water source for the capital city of Accra, as well as surrounding cities. Results of field testing validated the results of laboratory testing, showing the increase in PFAS binding by chain length. The magnitude of KSW for the BSA-SOMS passive samplers was higher in laboratory and field testing than for BCF from the literature. Although an equal value between the sampler equilibrium constants and BCF was not found, the higher binding affinity of the sampler improves limits of detection while still providing assessment of environmental impact.

Advisor

Edmiston, Paul

Department

Biochemistry and Molecular Biology

Disciplines

Analytical Chemistry | Biochemistry | Biochemistry, Biophysics, and Structural Biology | Chemistry | Environmental Chemistry | Laboratory and Basic Science Research

Keywords

PFAS, Perfluoroalkyl, Polyfluoroalkyl, bovine serum albumin, BSA, swellable organically modified silica, SOMS, passive sampler, passive sampling, discrete sampling, grab sampling, bioaccumulation, biomagnification, bioconcentration

Publication Date

2024

Degree Granted

Bachelor of Arts

Document Type

Senior Independent Study Thesis

Available for download on Tuesday, January 01, 2075

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