Identification and environmental occurrence of novel per- and polyfluoroalkyl substances derived from lithium-ion...

Global rise in electric vehicle adoption has prompted the rapid expansion of the lithium-ion battery (LIB) manufacturing and recycling industry. Many emerging classes of per- and polyfluoroalkyl substances (PFASs) have been incorporated into the LIB. However, the potential for PFAS emissions to the environment during the manufacturing and recycling processes of the LIB remains poorly understood. In this study, characteristic fragment ion-based non-target analysis was conducted to screen and identify unknown PFASs in surface water and sediment samples surrounding several LIB manufacturing and recycling factories. In total, 33 PFASs belonging to eight classes were identified in collected environmental samples with the confidence level of 1 - 3. Among these PFASs, environmental occurrence of N-ethyl perfluoromethanesulfonamide, N-hydroxymethyl trifluoromethanesulfonamide, and a series of bisperfluoroalkane sulfonimides (Bis-FASIs) is first discovered in this study. Furthermore, this study also investigated the sediment-water partitioning behaviors of these identified 33 PFASs. Results showed that the calculated mean log K_oc values in all sampling regions ranged from 0.51 ± 0.16 to 3.5 ± 0.34 for C₂-C₁₂ perfluoroalkyl carboxylates, 1.0 ± 0.31 to 2.9 ± 0.35 for C₁-C₈ perfluoroalkyl sulfonates, 1.2 ± 0.20 to 2.1 ± 0.19 for C₁-C₄ perfluoroalkane sulfonamides, and 1.9 ± 0.35 to 3.3 ± 0.16 for Bis-FASIs. In general, the log K_oc values of each class of PFASs linearly (p < 0.05) increased with increasing number of fluorinated carbons. This study discovered seven novel PFASs, which underscores the need to expand regulatory monitoring beyond legacy PFASs. The findings of this study also highlight the urgency of assessing ecological and human health risks posed by LIB-derived PFASs, particularly their potential for long-range transport and persistence in aquatic systems.