Date of Award

1-1-2021

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

College/School/Department

Department of Environmental Health Sciences

Content Description

1 online resource (xviii, 239 pages) : color illustrations.

Dissertation/Thesis Chair

David C Spink

Committee Members

Kurunthachalam Kannan, Patrick J Parsons, Lloyd R Wilson, Laura MacManus-Spencer

Keywords

Benthic macroinvertebrates (BMIs), Emerging pollutants, Environmental monitoring, Liquid chromatography–tandem mass spectrometry (LC–MS/MS), PFAS, Plant uptake, Perfluorinated chemicals, Environmental toxicology

Subject Categories

Analytical Chemistry | Environmental Sciences | Public Health

Abstract

Per- and polyfluoroalkyl substances (PFAS) constitute a broad class of anthropogenic chemicals that have been used in numerous industrial and consumer-product applications since the late 1940s. The environmental persistence of these compounds in combination with their widespread commercial use have led PFAS to be recognized as contaminants of concern on the global scale. Despite regulatory efforts calling for the decreased use of certain perfluorocarboxylic and -sulfonic acids referred to as “legacy” PFAS, these compounds continue to be detected in both environmental and biological matrices. Moreover, manufacturers have begun to replace the legacy PFAS with emerging alternatives for which the regulations are not established or are less strict, and the potential health effects are far less clear. For these reasons, studies of the disposition of legacy and emerging PFAS remain crucial for assessing their environmental contamination and potential impacts on public health.The goal of this dissertation was to address several knowledge gaps regarding the analytical measurement, environmental occurrence, and bioconcentration of PFAS, with a special emphasis on emerging compounds. First, a large-volume injection (LVI) sample preparation method for the determination of PFAS in drinking water was developed and validated. Evaluation of method performance indicated that, for some applications, LVI was a viable alternative to the standard methods employing solid-phase extraction (SPE). A second study was conducted to improve the analytical sensitivity for a class of emerging replacement PFAS, perfluoroethercarboxylic acids (PFECAs), using liquid chromatography–tandem mass spectrometry (LC–MS/MS). It was demonstrated that by making facile modifications to instrumental parameters, quantitative results can be obtained for these compounds which showed inadequate detection limits when using other methods. A third study was conducted to assess the use of freshwater aquatic insects/benthic macroinvertebrates (BMIs) for monitoring PFAS in the aquatic environment. To accomplish this, PFAS were measured in BMIs collected from two freshwater streams along with sediment and surface water simultaneously collected from the same sites. The results indicated that, although PFAS concentrations in sediment and water were not excessively high, elevated levels were measured in most of the BMI taxa examined. This observation suggests that PFAS contamination in the aquatic environment may be underestimated if only abiotic matrices are used for environmental monitoring. A final study was conducted to compare the uptake of legacy and emerging PFAS into edible plants. Three types of leafy vegetables were grown in hydroponic solutions containing different PFAS mixtures. Root and shoot concentration factors showed similar degrees of uptake among the different PFAS subclasses, suggesting that emerging compounds may have similar potential for bioaccumulation compared with their legacy predecessors.

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