Freshwater ecotoxicity characterization factors for PFASs

This research aims to address the data gaps in freshwater ecotoxicological characterization factors (CFs) for per- and polyfluoroalkyl substances (PFASs). These CFs are essential for incorporating the ecotoxicity impacts of PFAS emissions into life cycle assessments (LCAs). This study has three primary objectives: first, to calculate a comprehensive set of experimental aquatic ecotoxicity CFs for PFASs utilizing the USEtox model (version 2.13); second, to compare these newly derived CFs with those generated using the PFAS-adapted USEtox model; and finally, to test the hypothesis concerning a potential correlation between CFs and effect factors (EFs) with the number of perfluorinated carbons in PFASs. In this study, 367 PFASs were selected from the CompTox Chemicals Dashboard PFAS suspect lists and REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) registration dossiers. Experimental ecotoxicity data were extracted from CompTox Version 2.1.1 and REACH. Using both the USEtox model (version 2.13) and the PFAS-adapted USEtox model, CFs were calculated for 367 PFASs. Of these, 237 CFs were newly calculated using the HC20EC10eq-based methodology, enriching the representation of PFASs in LCA studies. The analysis revealed no correlation between the number of perfluorinated carbons and the calculated EFs and CFs using the USEtox models. This study covers only a small portion of the extensive list of millions of PFASs in PubChem, primarily due to data constraints and scarcity. Discrepancies between CFs generated by USEtox and PFAS-adapted USEtox are attributed to variations in foundational fate and exposure factor calculation methodologies, whereas ecotoxicity factors remained consistent. Consequently, it is suggested that CFs for PFASs are dependent on the modeling approach and require regular updates with the latest data to ensure accuracy and relevance.