Per- and polyfluoroalkyl substances (PFAS) in the contributing zone of the Edwards aquifer in south central Texas: 1. spatial and temporal distribution.

Authors

Claire Ong, Amna Afzal, Yongli Gao, Qi Fu

Published in

Environmental geochemistry and health. Volume 48. Issue 11. Jul 24, 2026. Epub Jul 24, 2026.

Abstract

This study, Part 1 of a comprehensive investigation, examines the distribution of per- and polyfluoroalkyl substances (PFAS) in water bodies in south central Texas. The study area includes the Cibolo Creek watershed within the Edwards aquifer recharge zone, Comal Springs, the Guadalupe River, the San Antonio River, and two wastewater treatment plants (WWTPs). A total number of seventy water samples were collected over a two-year period (February 2021-January 2023) to assess PFAS concentrations, speciation, and their spatial and temporal patterns. Twenty compounds are quantitatively detected, including 9 PFCAs, 4 PFSAs, 3 FTSAs, 2 PFECAs, and 2 PFESAs. The total PFAS concentration is in the range of 4.58 ng/L to 77.51 ng/L, with a mean value of 22.55 ng/L. Within subgroups, PFCA compounds have the highest concentrations. The individual PFAS also show significant variations in abundance, with PFOS exhibiting the highest mean concentration (3.99 ng/L). In the Cibolo Creek watershed, PFCAs and short-chain PFAA compounds decrease downstream in rural sites, while the opposite pattern is observed in urban sites. No apparent trend is present for FTSAs, PFESAs, or PFECAs. Comal Springs display the highest proportion of short-chain compounds, PFBA in particular, suggesting their favorable existence in groundwater most likely due to high mobility. As for seasonal fluctuations, short-chain compounds are at a minimum in summertime, with a two-fold increase in winter and spring months. While individual compounds show limited temporal trends, total PFAS concentrations increase up to 2.6 times during heavy rainfall events. The positive correlation between PFHxA and PFHpA, 8:2 FTS and PFDA, and PFBS and PFHxA, suggests the potential presence of shared industrial origins and/or precursor degradation pathways. The results of this study provide insight into temporal and spatial variations and patterns for both legacy and emerging PFAS, which would assist in further understanding possible aquifer contamination through impacted surfaces.

PMID:
42496774
Bibliographic data and abstract were imported from PubMed on 24 Jul 2026.

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