When
Where
Available in person and via zoom (see email for link)
Abstract
Per- and polyfluoroalkyl substances (PFAS) are ubiquitous emerging contaminants that occur at high concentrations at impacted soils, for example airports or military where historical uses of aqueous film-forming foams (AFFF) were applied or agricultural soils where contaminated amendements were utilized, leding to complex mixtures of PFAS present in topsoil. A fraction part of these PFAS can transform biotically into more persistent and mobile transformation products such as perfluoroalkyl acids (PFCAs), therefore causing a sink source for groundwater contamination and difficulting mass balance assessments and long-term risk evaluation. A quantitative understanding of PFAS generation rates from comingled precursor degradation is therefore critical for predicting plume evolution and groundwater concentrations over times and designing effective management strategies.
In this talk, a brief overview of the history, key chemical features, and applications of PFAS will be presented. Insights into biotransformation pathways and enzymatic reactions of different PFAS precursors will be discussed, along with recent laboratory methodologies to quantify PFCA generation rates at commingled contaminated sites with unknown PFAS precursors. The workflows include pre-cleaning of soil samples via column leaching experiments, determination of currently present PFAS as well as the total PFAS precursor reservoir using oxidation assays, and the setup of batch microcosm experiments. These data can be complemented by additional non-target screening approaches to elucidate the identity of PFAS precursors or potential transformation products, thereby confirming degradation mechanisms, 16S rRNA gene amplicon sequencing to assess the biodiversity of soil microorganisms, and chemometric analyses to clarify the role of enzymatic activities, among others.
Bio
Dr. Joel Fabregat-Palau is a Chemist with a Master’s degree in Analytical Chemistry and a PhD in Analytical and Environmental Chemistry from the University of Barcelona (Spain). He also completed a three-year research stay at the Guangzhou Institute of Geochemistry, Chinese Academy of Sciences. He is currently a postdoctoral researcher (assistant professor level) in the laboratory of Prof. Peter Grathwohl at the University of Tübingen (Germany), within the Department of Geosciences, Hydrogeochemistry section. His research focuses on the environmental behavior of different classes of pollutants, with particular emphasis on the fate and transport of per- and polyfluoroalkyl substances (PFAS) in soils and groundwater. His work includes the development and application of target and non-target analytical methods for trace contaminant detection, investigations of sorption and biodegradation processes, and the evaluation of remediation strategies at contaminated sites.
Dr. Joel Fabregat-Palau, Postdoctoral Researcher, Eberhard Karls Universitat Tubingen (Google Scholar Link)