Identification\nof\nNovel Iodinated Polyfluoroalkyl\nEther Acids and Other Emerging PFAS in Soils Using a Nontargeted Molecular\nNetwork Approach

Despite\nadvancements in high-resolution screening techniques,\nthe\nidentification of novel perfluoroalkyl and polyfluoroalkyl substances\n(PFAS) remains challenging without prior structural information. In\nview of this, we proposed and implemented a new data-driven algorithm\nto calculate spectral similarity among PFAS, facilitating the generation\nof molecular networks to screen for unknown compounds. Using this\napproach, 81 PFAS across 12 distinct classes were identified in soil\nsamples collected near an industrial park in Shandong Province, China,\nincluding the first reported occurrence of 12 iodine-substituted PFAS.\nAmong them, the standards of four iodine-substituted polyfluorinated\nether sulfonates (I-PFESA) were successfully synthesized, enabling\nstructural confirmation and subsequent quantitative analysis. Although\nthe median concentration of ∑I-PFESA (0.74 ng/g dw) in soil\nsamples was lower than that of ∑H-PFESA (hydrogen-substituted,\n61.96 ng/g dw) and ∑Cl-PFESA (chlorine-substituted, 2.98 ng/g\ndw), embryotoxicity assays in zebrafish revealed that 6:2 I-PFESA\nexhibited greater toxicity compared to 6:2 Cl-PFESA of the same chain\nlength. This highlights the need for a closer examination of the toxic\neffects of I-PFESA. Notably, the proposed algorithm, based on novel\nPFAS spectral similarity, provides new perspectives on the environmental\nbehavior and transformation of I-PFESA, although further investigation\nis required to elucidate the underlying mechanisms of their toxicity.