Despite growing concerns about human exposure to perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS), other poly- and perfluoroalkyl substances (PFASs) derived from aqueous film-forming foams (AFFFs) have garnered little attention. While these other PFASs may also be present in AFFF-impacted drinking water, their removal by conventional drinking-water treatment is poorly understood. This study compared the removal of 30 PFASs, including 13 recently discovered PFASs, from an AFFF-impacted drinking water using carbonaceous sorbents (i.e., granular activated carbon, GAC). The approach combined laboratory batch experiments and modeling: batch sorption data were used to determine partition coefficients (Kd) and calibrate a transport model based on intraparticle diffusion-limited sorption kinetics, which was used to make forward predictions of PFAS breakthrough during GAC adsorption. While strong retention was predicted for PFOS and PFOA, nearly all of the recently discovered polyfluorinated chemicals and PFOS-like PFASs detected in the AFFF-impacted drinking water were predicted to break through GAC systems before both PFOS and PFOA. These model breakthrough results were used to evaluate a simplified approach to predicting PFAS removal by GAC using compound-specific retention times on a C18 column (RTC18). Overall, this study reveals that GAC systems for the treatment of AFFF-impacted sources of water for PFOA and PFOS likely achieve poor removal, when operated only for the treatment of PFOS and PFOA, of many unmonitored PFASs of unknown toxicity.
Bibliographical noteFunding Information:
We thank the scholarship support for X.X. from the China Scholarship Council. We thank Dr. Aniela Burant from the Colorado School of Mines (CSM) for help in sample analysis and Dr. Krista Barzen-Hanson of Oregon State University (OSU) for help in identifying the PFASs. This project was supported by the National Natural Science Foundations of China (grant no. 21425730). We also thank D. Werner of Newcastle University; C. Schaefer of CDM Smith; T. Cath and C. Bellona of CSM,; J. Field and K. Barzen-Hanson of OSU; and S. Gormley, S. Thomas, and B. Malyk of AMEC Foster- Wheeler for helpful comments during the development of this manuscript.
© 2017 American Chemical Society.