| Autor: |
Jensen CR; Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695, United States., Genereux DP; Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695, United States., Solomon DK; Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112, United States., Knappe DRU; Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States., Gilmore TE; Conservation and Survey Division, School of Natural Resources, University of Nebraska - Lincoln, Lincoln, Nebraska 68588, United States.; Biological Systems Engineering Department, University of Nebraska - Lincoln, Lincoln, Nebraska 68588, United States. |
| Abstrakt: |
Per- and polyfluoroalkyl substances (PFAS) are known to be highly persistent in groundwater, making it vital to develop new approaches to important practical questions such as the time scale for future persistence of PFAS in contaminated groundwater. In the approach presented here, groundwater from beneath streambeds was analyzed for PFAS and age-dated using SF 6 and 3 H/ 3 He. The results were coupled with groundwater flux measurements in a convolution approach to estimate past and future PFAS concentrations in groundwater discharge to the streams. At our test site near the Cape Fear River (CFR) of North Carolina, PFAS were detected in groundwater up to 43 years old, suggesting that some PFAS entered groundwater immediately or shortly after fluorochemical production began at the nearby Fayetteville Works. Results are consistent with little to no retardation in groundwater for perfluoroethers such as hexafluoropropylene oxide-dimer acid (HFPO-DA) and perfluoro-2-methoxypropanoic acid (PMPA), the two most abundant PFAS, with mean concentrations of 229 and 498 ng/L, respectively. Future PFAS concentrations in groundwater discharge to streams were estimated to remain above current MCL or health advisory levels through at least 2050 or 2060 (using 3 H/ 3 He and SF 6 , respectively). Recent atmospheric deposition data suggest lower but non-negligible amounts of PFAS may continue to enter groundwater, likely further extending PFAS persistence in groundwater and the adjacent CFR. This approach shows promise for giving an overall perspective on persistence of PFAS in groundwater discharge from a broad contaminated area. |
