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Reconstructing Temporal PFAS Trends from a Sediment Core with Targeted and Nontargeted Analysis.
Citation:
Cashman, M., A. Robuck, M. Morales-Mcdevitt, J. Koelmel, T. Boving, AND M. Cantwell. Reconstructing Temporal PFAS Trends from a Sediment Core with Targeted and Nontargeted Analysis. University of Rhode Island Biological and Environmental Sciences Graduate Seminar, Kingston, RI, March 03, 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 an age-depth model of PFAS contamination over history in an urban mill pond. Initial analyses are constrained to the detection of 24 different PFAS compounds with analytical standards. However, other proxies such as EOF, TOP, and NTA are utilized to indicate the presence of previously undetected 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 of environmental matricies. This reserach will be presented to graduate students at the Universtiy of Rhode Island.
Description:
Background/Objectives. The use of Per- and polyfluoroalkyl substances (PFAS) in industrial applications predates analytical techniques for their identification in environmental matrices. One way to determine past PFAS contamination is through examining dated sediment cores. In this study, a sediment core was taken from an urban river in Rhode Island, USA. The sediment core was from a depositional area near former textile mills that were believed to use PFAS containing products. The core was radiometrically dated and analyzed for PFAS using a novel sediment method. A modified Total Oxidizable Precursor (TOP) assay was then performed to identify presence of PFAS Precursors. Approach/Activities. A 1.3m sediment core was extracted from an urban river for PFAS analysis. The core was radiometrically dated using 210-Pb and Cs-137 markers to develop an age-depth profile. PFAS were extracted from sediments at verified age-depths and quantified using isotopic dilution on a LC-MS/MS. From there, sediments underwent a novel TOP Assay to oxidize precursor compounds into detectable terminal products. PFAS concentrations pre- and post TOP Assay were compared to identify precursor presence in sediments. Results/Lessons Learned. Initial sediment concentrations showed temporal trends of PFAS preserved within the sediment record ranging from <1-50.4 ng/g sediment. Coupling these data with an age-depth model shows temporal trends of specific PFAS compounds. Specifics on the age-depth trends and TOP Assay will be available at the time of the presentation. These data identify legacy PFAS compounds previously used in manufacturing processes.