First report on the sources, vertical distribution and human health risks of legacy and novel per- and polyfluoroalkyl substances in groundwater from the Loess Plateau, China

• Published in: Journal of hazardous materials 2021-02, Vol.404 (Pt A), p.124134, Article 124134
• Main Authors: Zhou, Jian, Li, Shujian, Liang, Xiaoxue, Feng, Xuemin, Wang, Tiecheng, Li, Zhi, Zhu, Lingyan
• Format: Article
• Language: English
• Subjects: Alkanesulfonates; China; Environmental Monitoring; Fluorocarbons - analysis; Groundwater; Human health risk; Humans; Loess plateau; Per- and polyfluoroalkyl substances; PFAA-precursors; Sulfonic Acids; Water Pollutants, Chemical - analysis
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2020.124134

In this study, legacy and novel per and polyfluoroalkyl substances (PFASs) were measured in groundwater samples collected from the Loess Plateau of China to understand their occurrence, sources and health risks. The total concentration of PFASs ranged from 2.78 to 115 ng/L, with perfluorooctanoic acid (PFOA) as the dominant compound. Many emerging PFASs, including 6:2 fluorotelomer sulfonates (FTS), 6:2 chlorinated polyfluorinated ether sulfonic acid (Cl-PFESAs), ammonium 4,8-dioxa-3H-perfluorononanoate (ADONA), and hexafluoropropylene oxide (HFPO) homologues were frequently detected in 96.7–100% of the samples. Multiple source apportionment analyses indicated that the PFASs in the groundwater mainly originated from industrial activities, but in rural areas, agricultural activities also contributed. The total oxidizable precursor (TOP) assay indicated that there were substantial unknown precursors of perfluoroalkyl acids (PFAAs) in the groundwater samples. The total concentration of PFASs decreased with the well depth, while the PFAA-precursors displayed contrasting vertical profile trends, which might be due to the suppressed microbial transformation in the groundwater. The potential human health risk caused by PFAS exposure via drinking groundwater in the Loess Plateau was low, except for one site that was close to the industry bases. [Display omitted] •First report of a variety of emerging PFASs in groundwater in Loess Plateau.•PFOS was extensively substituted by its alternatives.•There were substantial unknown PFAA-precursors in the groundwater.•ΣPFASs and PFAA-precursors displayed contrasting vertical profile trends.•Deeper groundwater was safer in regard to the risks of PFASs exposure.