Reconstructing Temporal PFAS Trends from Sediment Cores with Multiple Approaches.
Citation:
Cashman, M., A. Robuck, M. Morales-Mcdevitt, J. Koelmel, T. Boving, AND M. Cantwell. Reconstructing Temporal PFAS Trends from Sediment Cores with Multiple Approaches. SETAC Europe 33rd Annual Meeting, Dublin, IRELAND, April 30 - May 04, 2023.
Impact/Purpose:
Per- and polyfluoroalkyl substances (PFAS) are a diverse suite of fluorinated chemicals found ubiquitously in the environment. This research uses a radiometrically dated sediment core to demonstrate a timeline of PFAS contamination over history in an urban river. Initial analyses are constrained to the detection of 24 different PFAS compounds with analytical standards. However, other PFAS detection proxies are utilized to indicate the presence of additional PFAS. This research highlights the ability for sediment cores to develop depositional timelines of environmental PFAS release, and also shows the importance of multiple proxies for detection. This reserach will be presented to a scientific community at SETAC Europe.
Description:
The use of Per- and polyfluoroalkyl substances (PFAS) in industrial applications predates analytical techniques for their identification in environmental matrices, leaving a gap in historical contamination records (Kissa et al., 2001). One way to determine past PFAS contamination is through examining radiometrically dated sediment cores. In this study, a sediment core was taken from an urban river in Rhode Island, USA. The sediment core was collected in a quiescent depositional area of a dammed mill pond near former mills that were suspected of using products containing PFAS. The core was radiometrically dated and analysed for PFAS using multiple techniques including a Total Oxidizable Precursor Assay (TOP), Extractable Organic Fluorine (EOF), and Nontarget Analysis (NTA). Results from NTA and radiometric dating were compared to determine co-occurrence of PFAS as a means of source identification. This research highlights the utility of a multi-analysis approach to characterize temporal PFAS trends in sediments. Through the hollisitic analysis of radioemtric dating, TA, and NTA, this sediment core is strong evidence of depositional history preserved within the millpond. This study highlights the utility of combining NTA with radiometric data and other proxies to elucidate temporal trends of environmental contaminants. In this case study, the hierarchical clustering distinguished several notable time periods of PFAS deposition. Most of the PFAS detected in TA and NTA were released into the environment in the mid-1970s. There were also groupings of different PFAS released more recently (2020-2000) and in the mid-1950s. Understanding the depositional history of environmental PFAS is important for understanding PFAS fate and long-term persistence in the environment. Results of this study are being paired with PFAS analysis of surface water, fish tissue, and suspended sediments to holistically assess the environment. This proposed workflow is being used in other sites across the USA to verify PFAS deposition.
