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S o m ic e iM m liig y ^ g i^ pubs.acs.org/joumal/estlcu Legacy and Emerging Perfluoroalkyl Substances Are Important Drinking Water Contaminants in the Cape Fear River Watershed of North Carolina Mei Elisa Arevalo/ Mark Strynar/ Andrew Lindstrom/ Michael Richardson/ Ben Kearns/ Adam Pickett,^ Chris Sm ith/ and Detlef R. U. Knappe2 ^Department of Civil and Environmental Engineering, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States ^Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States ^National Exposure Research Laboratory, U.S. Environmental Protection Agency Research, Triangle Park, North Carolina 27711, United States ^Cape Fear Public Utility Authority, Wilmington, North Carolina 28403, United States """Town of Pittsboro, Pittsboro, North Carolina 27312, United States #Fayetteville Public Works Commission, Fayetteville, North Carolina 28301, United States Supporting Information ABSTRACT: Long-chain per- and polyfluoroalkyl substances P o in ts (PFASs) are being replaced by short-chain PFASs and non-point m legacy PFASs fluorinated alternatives. For ten legacy PFASs and seven sources recently discovered perfluoroalkyl ether carboxylic acids PFPrOPrA ("GenX") (PFECAs), we report ( l ) their occurrence in the Cape Fear River (CFR) watershed, (2) their fate in water treatment processes, and (3) their adsorbability on powdered activated carbon (PAC). In the headwater region of the C FR basin, FFF 200 400 600 $00 aPFAS Concentration {ng/L) PFECAs were not detected in raw water of a drinking water treatment plant (DW TP), but concentrations of legacy PFASs were high. The U.S. Environmental Protection Agency's I i I OH Fiuorochemi F F F Manufacturer PFPrOPrA {"6 enX"| lifetime health advisory level (70 ng/L) for perfluorooctane- sulfonic acid and perfluorooctanoic acid (PFOA) was exceeded on 57 of 127 sampling days. In raw water of a DWTP downstream of a PFAS manufacturer, the mean concentration of perfluoro-2-propoxypropanoic acid (PFPrOPrA), a replacement for PFOA, was 631 ng/L (n = 37). Six other PFECAs were detected, with three exhibiting chromatographic peak areas up to 15 times that of PFPrOPrA At this DWTP, PFECA removal by coagulation, ozonation, biofiltration, and disinfection was negligible. The adsorbability of PFASs on PAC increased with increasing chain length. Replacing one CF2 group with an ether oxygen decreased the affinity of PFASs for PAC, while replacing additional C F2 groups did not lead to further affinity changes. INTRODUCTION Per- and polyfluoroalkyl substances (PFASs) are extensively used in the production of plastics, water/stain repellents, firefighting foams, and food-contact paper coatings. The widespread occurrence of PFASs in drinking water sources is closely related to the presence of sources such as industrial sites, military fire training areas, civilian airports, and wastewater treatment plants.1 Until 2000, long-chain perfluoroalkyl sulfonic acids [CnF 2n+1SO sH; n > 6 (PFSAs)] and perfluoro alkyl carboxylic acids [C,,F2n+1COO H ; n > 7 (PFCAs)] were predominantly used.2 Accumulating evidence about the ecological persistence and human health effects associated with exposure to long-chain PFASs2,4 has led to an increased level of regulatory attention. Recently, the U.S. Environmental Protection Agency (USEPA) established a lifetime health advisory level (H A L) o f 70 n g /L for the sum of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFO S) concentrations in drinking water.VJ Over the past decade, production of long-chain PFASs has declined in Europe and North America, and manufacturers are moving toward short-chain PFASs and fluorinated alternatives.' 10 Some fluorinated alternatives were recently identified,'u but others remain unknown12 14 because they are either proprietary or manufacturing byproducts. Received: October 13, 2016 Revised: November 8, 2016 Accepted: November 10, 2016 Published: November 10, 2016 ACS Publications XXXX American Chemical Society A DOI: 10.1021 /ac$.A`T|.dti,6h00S93 Environ. Sci. Technol. Let1. XXXX, XXX, XXX-XXX Sierra Club v. EPA 18cv3472 NDCA Tier 10 ED 002061 00270551-00001 Environmental Science & Technology Letters One group of fluorinated alternatives, perfluoroalkyl ether carboxylic acids (PFECAs), was recently discovered in the Cape Fear River (CFR) downstream of a PFAS manufacturing facility.11 Identified PFECAs included perfluoro-2-methoxyacetic acid (PFMOAA), perfluoro-3-methoxypropanoic acid (PFMOPrA), perfluoro-4-methoxybutanoic acid (PFMOBA), perfluoro-2-propoxypropanoic acid (PFPrOPrA), perfluoro(3,5-dioxahexanoic) acid (PF02H xA ), perfluoro(3,5,7-trioxaoctanoic) acid (P F 0 3 0 A ), and perfluoro (3,5,7,9-tetraoxadecanoic) acid (P F 04D A ) (Table SI and Figure S i) . The ammonium salt of PFPrOPrA is a known PFOA alternativeij that has been produced since 2010 with the trade name "GenX". To the best of our knowledge, the only other published PFECA occurrence data are for PFPrOPrA in Europe and China,5'' and no published data about the fate of PFECAs during water treatment are available. Except for a few studies (most by the manufacturer),16 little is known about the toxicity, pharmacokinetic behavior, or environmental fate and transport of PFECAs. The strong C --F bond makes PFASs refractory to abiotic and biotic degradation,21 and most water treatment processes are ineffective for legacy PFAS removal.2" " Processes capable of removing PFCAs and PFSAs include nanofiltration,' reverse osm osis,' ' ion exchange,2 ''2'2 and activated carbon adsorp tion,"0'"2 with activated carbon adsorption being the most widely employed treatment option. The objectives of this research were ( l ) to identify and quantify the presence of legacy PFASs and emerging PFECAs in drinking water sources, (2) to assess PFAS removal by conventional and advanced processes in a full-scale drinking water treatment plant (DW TP), and (3) to evaluate the adsorbability of PFASs on powdered activated carbon (PAC). MATERIALS AND METHODS Water Samples. Source water of three DWTPs treating surface water in the CFR watershed was sampled between June 14 and December 2, 2013 (Figure S2). Samples were collected from the raw water tap at each DWTP daily as either 8 h composites (DWTP A, 127 samples) or 24 h composites (DWTP B, 73 samples; DWTP C, 34 samples). Samples were collected in 250 mL HDPE bottles and picked up (DWTPs A and B) or shipped overnight (DWTP C) on a weekly basis. All samples were stored at room temperature until they were analyzed (within 1 week of receipt). PFAS losses during storage were negligible on the basis of results of a 70 day holding study at room temperature. On August 18, 2014, grab samples were collected at DWTP C after each unit process in the treatment train [raw water ozonation, coagulation/flocculation/sedimen tation, settled water ozonation, biological activated carbon (BAC) filtration, and disinfection by medium-pressure UV lamps and free chlorine]. Operational conditions of DWTP C on the sampling day are listed in Table S2. Samples were collected in 1 L HDPE bottles and stored at room temperature until they were analyzed. On the same day, grab samples of C FR water were collected in six 20 L HDPE carboys at William O. Huske Lock and Dam downstream of a PFAS manufacturing site and stored at 4 C until use in PAC adsorption experiments (background water matrix characteristics listed in Table S3). Adsorption Experiments. Adsorption of PFASs by PAC was studied in batch reactors (amber glass bottles, 0.45 L of C FR water). PFECA adsorption was studied at ambient concentrations (''-1000 n g/L PFPrOPrA, chromatographic peak areas of other PFECAs being approximately 10--800% of the PFPrOPrA area). Legacy PFASs were present at low concentrations (<40 ng/L) and spiked into C FR water at ~1000 n g/L each. Data from spiked and nonspiked experi ments showed that the added legacy PFASs and methanol ( l ppmT) from the primary stock solution did not affect native PFECA removal. A thermally activated, wood-based PAC (PicaHydro MP23, PICA USA, Columbus, OH; mean diameter of 12 fim, BET surface area of 1460 m2/ g ) 10 proven to be effective for PFAS removal in a prior study2'2 was used at doses of 30, 60, and 100 m g/L. These doses represent the upper feasible end for drinking water treatment. Samples were taken prior to and periodically after PAC addition for PFAS analysis. PFAS losses in PAC-free blanks were negligible. PFAS Analysis. Information about analytical standards and liquid chromatography--tandem mass spectrometry (L C --M S / M S) methods for PFAS quantification is provided in the Sirpporting Informat!on. S RESULTS AND DISCUSSION Occurrence of PFASs in Drinking Water Sources. Mean PFAS concentrations in source water of three DWTPs treating surface water from the C FR watershed are shown in Figure 1. PFBA .. .... Si Pi'PeA FfBS ;ii F f BxA 8 PFHxS s PmpA IPFOS iS PFOA ..... tt PFPtOF'i A Ccnrinninuv A M i l r; 27 ' Comrnunirv SI n--73 ! Community C : M M n~34 0 tOO 400 600 800 Average concentration in tirinking water source (ng/L> Figure 1. Occurrence of PFASs at drinking water intakes in the CFR watershed. Concentrations represent averages of samples collected between June and December 2013. Individual samples with concentrations below the quantitation limits (QLs) were considered as 0 when calculating averages, and average concentrations below the QLs were not plotted. In communities A and B, only legacy PFASs were detected (mean ]TPFAS of 355 n g/L in community A and 62 n g/L in community B). Detailed concentration data are shown in Table S6 and Figure S3. In community A, PFCAs with four to eight total carbons, perfluorohexanesulfonic acid (PFHxS), and PFO S were detected at mean concentrations above the quantitation limits (Q Ls). During the 127 day sampling campaign, the sum concentration of PFOA and PFOS exceeded the USEPA HAL of 70 n g/L on 57 days. The mean sum concentration of PFOA and PFOS over the entire study period was 90 ng/L, with approximately equal contributions from PFOS (44 ng/L ) and PFOA (46 ng/L). Maximum PFOS and PFOA concentrations were 346 and 137 ng/L, respectively. Similar PFOS and PFOA concentrations were observed in the same area in 2006,33 suggesting that PFAS source (s) upstream of community A have continued negative impacts on drinking water quality. Also, our data show that legacy PFASs remain as surface water contaminants of concern even though their production was recently phased out in the United States. It is important to note, however, that among the PFCAs that were measured in both 2006 and 2013 (PFHxA to PFDA), the P F C A spciation shifted from long-chain ( ~ 8 0 --85% C,,F2n+1CO O H ; n = 7 --9) in 2006 to short-chain (76% C,,F2,,+]COO H ; n = 5--6) in 2013. In contrast, the PFSA spciation was dominated by PFOS in both 2006 and 2013. B DOI: : 0. : 0Jl/at:s,e5tletT.5b398 Environ. Sei. Technol. Lett. XXXX, XXX, XXX- XXX Sierra Club v. EPA 18cv3472 NDCA Tier 10 ED 002061 00270551-00002 Environmental Science & Technology Letters Relating total PFAS concentration to average daily streamflow (Figure S4) illustrated a general trend of low PFAS concentrations at high flow, and high concentrations at low flow, consistent with the hypothesis of one or more upstream point sources. In community B, perfluorobutanoic acid (PFBA) and perfluoropentanoic acid (PFPeA) were most frequently detected with mean concentrations of 12 and 19 ng/L, respectively. Mean PFOA and PFOS concentrations were below the QLs, and the maximum sum concentration of PFOA and PFOS was 59 ng/L. Lower PFAS concentrations in community B relative to community A can be explained by the absence of substantive PFAS sources between the two communities, dilution by tributaries, and the buffering effect o f Jordan Lake, a large reseivoir located between communities A and B. In community C (downstream of a PFAS manufacturing site), only mean concentrations of PFBA and PFPeA were above the QLs. The relatively low concentrations of legacy PFASs in the finished drinking water of community C are consistent with results from the USEPA's third unregulated contaminant monitoring rule for this D W T P .2 However, high concentrations of PFPrOPrA were detected (up to ~4500 ng/ L). The average PFPrOPrA concentration (631 ng /L ) was approximately 8 times the average summed PFCA and PFSA concentrations (79 ng/L). Other PFECAs had not yet been identified at the time of analysis. Similar to communities A and B, the highest PFAS concentrations for community C were also observed at low flow ( Figure 54). Stream flow data were used in conjunction with PFPrO PrA concentration data to determine PFPrOPrA mass fluxes at the intake of DWTP C. Daily PFPrOPrA mass fluxes ranged from 0.6 to 24 kg/day with a mean of 5.9 kg/day. Fate of PFASs in Conventional and Advanced Water Treatment Processes. To investigate whether PFASs can be removed from impacted source water, samples from DWTP C were collected at the intake and after each treatment step. Results in Figure 2 suggest conventional and advanced treatment processes (coagulation/flocculation/sedimentation, raw and settled water ozonation, BAC filtration, and disinfection by medium-pressure UV lamps and free chlorine) did not remove legacy PFASs, consistent with previous studies.2" The data further illustrate that no measurable PFECA removal occurred in this DWTP. Concentrations of some PFCAs, PFSAs, PFMOPrA, PFPrOPrA, and PFMOAA may have increased after ozonation, possibly because of the oxidation o f precursor com pounds/ ' Disinfection with medium-pressure UV lamps and free chlorine (located between the BAC effluent and the finished water) may have decreased concentrations of PFMOAA, PFMOPrA, PFMOBA, and PFPrOPrA, but only to a limited extent. Small concentration changes between treatment processes may also be related to temporal changes in source water PFAS concentrations that occurred in the time frame corresponding to the hydraulic residence time of the DWTP. Results in Figure 2 further illustrate that the PFAS signature of the August 2014 samples was similar to the mean PFAS signature observed during the 2013 sampling campaigns shown in Figure 1; i.e., PFPrOPrA concentrations (400--500 ng/L) greatly exceeded legacy PFAS concentrations. Moreover, three PFECAs (PFMOAA, PF02HxA, and P F 0 3 0 A ) exhibited peak areas 2 --113 times greater than that of PFPrOPrA (Figure 2b). '<v Raw wauvr - /' Pry-ozona cfiiiwnf: r Settled water Setfied-ozoneeffluent I BAC tiffiut'nt . \ Finished water -------- ~~~-- \ s t ---------- PFPrOPrA PFBA s? PFNA ??: PFOA 100 200 300 400 500 600 700 800 Concentration of traditional PFASs at a WIT m Community C Ing/U PFPeA M PH ixA Si PFHp S; PFOA PPBS P FH $ PFOS (W Flaw water s \ Pie-ozone effluent | jj Setfied water | \ Settled-ozone effluent \1i \1;i BAC effluent | jj Finished water ss: ijljljij PPPiOPrA PFG2HxA 0 50,1X10 100,00} 130,000 200,000 250,000 300,000 Peak area counts of emerging PFASs at a WFP m Comirumity C PFMOAA St PFOBOA ITVJUFrA PF04PA $ PFMOBA Figure 2. Fate of (a) legacy PFASs and PFPrOPrA and (b) PFECAs through a full-scale water treatment plant. Because authentic standards were not available for PFECAs other than PFPrOPrA, chromato graphic peak area counts are shown in panel h. PFPrOPrA data are shown in both panels and highlighted with dashed ovals for reference. Compounds with concentrations below the QLs were not plotted. The existence of high levels of emerging PFASs suggests a need for their incorporation into routine monitoring. Adsorption of PFASs by PAC. PAC can effectively remove long-chain PFCAs and PFSAs, but its effectiveness decreases with decreasing PFAS chain length.24'2''2 ' It is unclear, however, how the presence of ether group (s) in PFECAs impacts adsorbability. After a contact time of 1 h, a PAC dose of 100 m g/L achieved >80% removal of legacy PFCAs with total carbon chain lengths of >7. At the same PAC dose, removals were 95% for P F 0 4 D A and 54% for P F 0 3 0 A , but <40% for other PFECAs. Detailed removal percentage data as a function of PAC contact time are shown in Figure S5. There was no meaningful removal of PFMOBA or PFMOPrA, and the variability shown in Figure S5 is most likely associated with analytical variability. PFMOAA could not be quantified by the analytical method used for these experiments; however, on the basis of the observations that PFAS adsorption decreases with decreasing carbon chain length and that PFECAs with one or two more carbon atoms than PFMOAA (i.e., PFMOPrA and PFMOBA) exhibited negligible removal (Figure 3), it is expected that PFMOAA adsorption is also negligible under the tested conditions. To compare the affinity of different PFASs for PAC, PFAS removal percentages were plotted as a function of PFAS chain length [the sum of carbon (including branched), ether oxygen, and sulfur atoms] (Figure 3b). The adsorbability of both legacy and emerging PFASs increased with increasing chain length. PFSAs were more readily removed than PFCAs of matching chain length, a result that agrees with those of previous C DOI: : 0. : 0Jl/at:s,e5tletT.5b398 Environ. Sei. Technol. Lett. XXXX, XXX, XXX- XXX Sierra Club v. EPA 18cv3472 NDCA Tier 10 ED 002061 00270551-00003 Environmental Science & Technology Letters PFECAs PFECAs ? PESAs Figure 3. PFAS adsorption on PAC (a) at carbon doses of 30, 60, and 100 m g/L and (b) as a function of PFAS chain length. The PAC contact time in CFR water was 1 h. Legacy PFASs were spiked at ~1000 ng/L, and the emerging PFASs were at ambient concentrations. Figures show average PFAS removal percentages, and error bars show one standard deviation of replicate experiments. studies.24'2^'29 PFECAs exhibited adsorbabilities lower than those of PFCAs o f the same chain length (e.g., PFMOBA < PFHxA), suggesting that the replacement of a C F2 group with an ether oxygen atom decreases the affinity of PFASs for PAC. However, the replacement of additional C F2 groups with ether groups resulted in small or negligible affinity changes among the studied PFECAs (e.g., PFMOBA ~ PF02H xA, PFPrOPrA ~ P F 0 3 0 A ). Alternatively, if only the number of perfluorinated carbons were considered as a basis of comparing adsorbability, the interpretation would be different. In that case, with the same number of perfluorinated carbons, PFCAs have an affinity for PAC higher than that of monoether PFECAs (e.g., PFPeA > PFMOBA) but an affinity lower than that of multi-ether PFECAs (e.g., PFPeA < P F 0 3 0 A ). To the best of our knowledge, this is the first paper reporting the behavior of recently identified PFECAs in water treatment processes. We show that PFECAs dominated the PFAS signature in a drinking water source downstream of a fluorochemical manufacturer and that PFECA removal by many conventional and advanced treatment processes was negligible. Our adsorption data further show that PFPrOPrA ("GenX") is less adsorbable than PFOA, which it is replacing. Thus, PFPrOPrA presents a greater drinking water treatment challenge than PFOA does. The detection of potentially high levels of PFECAs, the continued presence of high levels of legacy PFASs, and the difficulty of effectively removing legacy PFASs and PFECAs with many water treatment processes suggest the need for broader discharge control and contaminant monitoring. ASSOCIATED CONTENT Q Supporting Information The Supporting Information is available free of charge on the ACS Publications website at DO L 10.1021/acs.estiett6b00398. Six tables, five figures, information about PFASs, analytical methods, and detailed results (PDF) m AUTHOR INFORMATION Corresponding Author *E-mail: msun8yi.Hincc.edu. Phone: 704-687-1723. ORCID.. Mei Sun: 0000.0001-5854-9862 Notes The views expressed in this article are those of the authors and do not necessarily represent the views or policies of the USEPA. The authors declare no competing financial interest. S ACKNOWLEDGMENTS This research was supported by the National Science Foundation (Grant 1550222), the Water Research Foundation (Project 4344), and the North Carolina Urban Water Consortium. S REFERENCES ( l ) Hu, X. C.; Andrews, D. Q.; Lindstrom, A. B.; Bruton, T. A.; Scbaider, L. A.; Grandjean, P.; Lohmann, R.; Carignan, C. C.; Blum, A.; Balan, S. A.; et al. Detection of poly- and perfluoroalkyl substances (PFASs) in U.S. drinking water linked to industrial sites, military fire training areas, and wastewater treatment plants. Environ. Sci. Technol. Lett. 2016, 3 (10), 344-350. D DOI: : 0. : 0Jl/at:s,e5tletT.5b398 Environ. Sci. Technol. Lett. XXXX, XXX, XXX- XXX Sierra Club v. 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Determination of adsorbable organic fluorine from aqueous environ mental samples by adsorption to polystyrene-divinylbenzene based activated carbon and combustion ion chromatography. J. Chromatogr. A 2013, 129S, 82-89. (14) Willach, S.; Brauch, H. J.; Lange, F. T. Contribution of selected perfluoroalkyl and polyfluoroalkyl substances to the adsorbable organically bound fluorine in German rivers and in a highly contaminated groundwater. Chemosphere 2016, 145, 342--350. (15) Heydebreck, F.; Tang, J.; Xie, Z.; Ebinghaus, R Alternative and legacy perfluoroalkyl substances: Differences between european and Chinese river/estuary systems. Environ. Sci. Technol. 2015, 49 (14), 8386-8395. (16) Gannon, S. A ; Fasano, W. J.; Mawn, M. P.; Nabb, D. L.; Buck, R C.; Buxton, L. W.; Jepson, G. W.; Frame, S. R Absorption, distribution, metabolism, excretion, and kinetics of 2,3,3,3-tetrafluoro2-(heptafluoropropoxy)propanoic acid ammonium salt following a single dose in rat, mouse, and cynomolgus monkey. Toxicology 2016, 340, 1-9. (17) Hoke, R A ; Ferrell, B. D.; Sloman, T. L.; Buck, R C.; Buxton, L. W. Aquatic hazard, bioaccumulation and screening risk assessment for ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate. Chemosphere 2016, 149, 336--342. (18) Caverly Rae, J. M.; Craig, L.; Slone, T. W.; Frame, S. R ; Buxton, L. W.; Kennedy, G. L. Evaluation of chronic toxicity and carcinogenicity of ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate in Sprague--Dawley rats. Toxicol. Rep. 2015, 2, 939-949. (19) Wang, j.; Wang, X.; Sheng, N.; Zhou, X.; Cui, R ; Zhang, H.; Dai, J. RNA-sequencing analysis reveals the hepatotoxic mechanism of perfluoroalkyl alternatives, H FP02 and H FP04, following exposure in mice. J. Appl. Toxicol. 2016. (20) Gomis, M. 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EPA 18cv3472 NDCA Tier 10 ED 002061 00270551-00005 Supporting information Legacy and Emerging Perfluoroalkyl Substances Are Important Drinking Water Contaminants in the Cape Fear River Watershed of North Carolina Supporting information includes analytical method description, 6 tables, and 5 figures. Mei Sun12-*, Elisa Arevalo2, Mark Strynar3, Andrew Lindstrom3, Michael Richardson4, Ben Kearns4, Adam Pickett5, Chris Smith6, and Detlef R.U. Knappe2 1Department of Civil and Environmental Engineering University of North Carolina at Charlotte Charlotte, North Carolina 28223, USA 2Department of Civil, Construction, and Environmental Engineering North Carolina State University Raleigh, North Carolina 27695, USA 3National Exposure Research Laboratory U.S. Environmental Protection Agency Research Triangle Park, North Carolina 27711, USA 4Cape Fear Public Utility Authority Wilmington, North Carolina 28403, USA 5Town of Pittsboro Pittsboro, North Carolina 27312, USA 6Fayetteville Public Works Commission Fayetteville, North Carolina 28301, USA '`'Corresponding Author Email: msun8@uncc.edu; Phone: 704-687-1723 Page 1 of 12 Sierra Club v. EPA 18cv3472 NDCA Tier 10 ED 002061 00270551-00006 Analytical standards: PFASs studied in this research are listed in Table SI. For legacy PFASs, native and isotopically labeled standards were purchased from Wellington Laboratories (Guelph, Ontario, Canada). Native PFPrOPrA was purchased from Thermo Fisher Scientific (Waltham, MA). No analytical standards were available for other PFECAs. PFAS quantification: PFAS concentrations in samples from DWTPs and adsorption tests were determined by liquid chromatography tandem mass spectrometry (LC-MS/MS) using a largevolume (0.9 mL) direct injection method. An Agilent 1100 Series LC pump and PE Sciex API 3000 LC-MS/MS system equipped with a 4.6 mm x 50 mm HPLC column (Kinetex C18 5pm 100A, Phenomenex Inc.) was used for PFAS analysis. The eluent gradient is shown in Table S4 in SI. All samples, calibration standards, and quality control samples were spiked with isotopically labeled internal standards, filtered through 0.45-pm glass microfiber syringe filters, and analyzed in duplicate. The MS transitions for PFAS analytes and internal standards are shown in Table S5 in SI. The quantitation limit (QL) was 25 ng/L for PFOS and perfluorodecanoic acid, and 10 ng/L for other legacy PFASs and PFPrOPrA. The QL was defined as the first point of the standard curve, for which the regression equation yielded a calculated value within 30% error. For PFECAs without analytical standards, chromatographic peak areas are reported. PFAS concentrations along the treatment train of DWTP C were analyzed using a Waters Acquity ultra performance liquid chromatograph interfaced with a Waters Quattro Premier XE triple quadrupole m ass spectrometer (Waters, Milford, MA, USA) after solid phase extraction. Method details are described elsewhere.1The QL for all PFASs with analytical standards was 0.2 ng/L, and peak areas were recorded for PFECAs without standards. Sierra Club v. EPA 18cv3472 NDCA Tier 10 Page 2 of 12 ED 002061 00270551-00007 Table SI. Perfluoroalkyl substances (PFASs) detected in the Cape Fear River (CFR) watershed Compound Molecular weight Formula Perfluorocarboxylic acids (PFCAs) CAS# # of perfluorinated carbons Perfluorobutanoic acid (PFBA) 214.0 C4HF7O2 375-22-4 3 Perfluoropentanoic add (PFPeA) 264.0 C5HF9O2 2706-90-3 4 Perfluorohexanoic acid (PFHxA) Perfluoroheptanoic acid (PFHpA) 314.1 C6HF11O2 307-24-4 5 364.1 C7HF13O2 375-85-9 6 Perfluorooctanoic acid (PFOA) 414.1 CsHFisCh 335-67-1 7 Perfluorononanoic acid (PFNA) 464.1 C9HF17O2 375-95-1 8 Perfluorodecanoic acid (PFDA) 514.1 C10HF19O2 335-76-2 9 Perfluorosulfonic acids (PFSAs) Perfluorobutane sulfonic acid (PFBS) 300.1 C4HF9SO.3 375-73-5 4 Perfluorohexane sulfonic ad d (PFHxS) 400.1 CeHFisSOs 355-46-4 6 Perfluorooctane sulfonic acid (PFOS) 500.1 C8HF17SO3 1763-23-1 8 Perfluoroalkyl ether carboxylic acids with one ether group (mono-ether PFECAs) Perfluoro-2-methoxyacetic ad d (PFMOAA) 180.0 GHFsOs 674-13-5 2 Perfluoro-3-methoxypropanoic acid (PFMOPrA) 230.0 C4 HF7O3 377-73-1 3 Perfluoro-4-methoxybutanoic ad d (PFMOBA) 280.0 C5 HF9O3 863090-89-5 4 Perfluoro-2-propoxypropanoic acid (PFPrOPrA ) 330.1 CHFiiOs 13252-13-6 5 Perfluoroalkyl ether carboxylic acids with multiple ether group (multi-ether PFECAs) Perfluoro(3,5-dioxahexanoic) add (PF0 2 HxA) 246.0 C4HF7O4 39492-88-1 3 Perfluoro(3,5,7-trioxaoctanoic) ad d (PF030A ) 312.0 G H F 9O5 39492-89-2 4 Perfluoro(3,5/7/9-tetraoxadecanoic) acid (PF04DA) 378.1 1 CHFnOe 39492-90-5 5 Chain length (including all C, O and S) 4 5 6 7 8 9 10 5 7 9 4 5 6 7 6 8 10 Page 3 of 12 Sierra Club v. EPA 18cv3472 NDCA Tier 10 ED 002061 00270551-00008 Table S2. Operational conditions of DWTP C on sampling day (August 18, 2014) Parameter Raw water ozone dose Raw water total organic carbon concentration Aluminum sulfate coagulant dose Coagulation pH Settled water ozone dose Settled water total organic carbon concentration Empty bed contact time in biological activated carbon filters Medium pressure UV dose Free chlorine dose Free chlorine contact time Value 3.1 mg/L 6.0 mg/L 43 mg/L 5.70 1.3 mg/L 1.90 mg/L 9.4 minutes for granular activated carbon layer 2.3 minutes for sand layer 25 mj/cm2 1.26 mg/L as Cb 17.2 hours Table S3. Water quality characteristics of surface water used in adsorption tests N on-purgeable organic carbon (m g/L) 9.036 Ultraviolet absorbance at a w avelength of 254 nm 0.399 pH 7.53 A lk alin ity (m g/L as C aC O ) 19 C o n d u ctiv ity (uS cm) 133.5 Table S4. LC gradient method for PFAS analysis Time (min) Mobile Phase A% (v/v) Mobile Phase B% Flow Rate (mL/min) 0-2 95 5 0.9 2-5 95 5 0.9 5-10 95-> 10 O G\ LO 0.9 10 -10.1 10 90 0.9 10.1 -1 4 10 ->95 90 --> 5 0.9 Mobile phase A: 2 mM ammonium acetate in ultrapure water with 5% methanol Mobile phase B: 2 mM ammonium acetate in acetonitrile with 5% ultrapure water Sierra Club v. EPA 18cv3472 NDCA Tier 10 Page 4 of 12 ED 002061 00270551-00009 Table S5. MS transitions for PFAS Analysis Legacy PFASs PFECAs Internai standards Compound PFBA PFPeA PFHxA PFHpA PFOA PFNA PFDA PFBS PFHxS PFOS PFMOAA PFMOPrA PFMOBA PFPrOPrA PF02HxA PF030A PF04DA Perfluoro-n-[l,2,3,4-13C4]butanoic acid (13C4-PFBA) Perfluoro-n-[l,2-13C2]hexanoic acid (13C2-PFHxA) Perfluoro-n-[ l /2,3,4-13C2]octanoic acid (13C4-PFOA) Perfluoro-n-[l/2-13C2]decanoic acid (13C2-PFDA) Sodium perfluoro-1 hexane[1802]sulfonate (1802-PFHxS) Sodium perfluoro-1-[1,2,3,4-'3C4]octane sulfonate (13C4-PFOS) MS/MS Transition 212.8 168.8 Internai standard 13C4-PFBA 262.9 218.8 13C2- PFHxA 313.6 -->268.8 j 13C2- PFHxA 362.9 -->318.8 ! 13C4- PFOA 413.0 368.8 13C4- PFOA 463.0 418.8 13C4- PFOA 513.1 68.8 13C2-PFDA 299.1 98.8 1802-PFHxS 399.1 98.8 1802-PFHxS 498.9 98.8 13C4-PFOS 180.0 85.0 N/A 229.1 184.9 N/A 279.0 234.8 N/A 329.0 -->284.7 j 13C2-PFHxA 245.1 -> 85.0 i N/A 311. - 84.9 N/A 377.1 >85.0 N/A 217.0 -> 172 315.1 -> 269.8 417.0 -> 372.0 515.1 -> 469.8 Not applicable 403.1 -> 83.8 502.9 -> 79.9 Sierra Club v. EPA 18cv3472 NDCA Tier 10 Page 5 of 12 ED 002061 00270551-00010 Table S6. Maximum, minimum, mean and median concentrations (ng/L) of PFASs at three drinking water intakes. * PFBA PFPeA PFHxA PFHpA PFOA PFNA PFDA PFBS PFHxS PFOS PFPrOPrA PFOA+PFOS I PFASs** max 99 191 318 324 137 38 35 80 193 346 <10 447 1502 Community A min median <10 26 14 44 <10 48 <10 39 <10 34 <10 <10 <25 <25 <10 <10 <10 10 <25 29 <10 <10 0 64 18 212 mean 33 62 78 67 46 <10 <25 <10 14 44 <10 90 355 Community B max min median 38 <10 12 38 <10 19 42 <10 <10 85 <10 <10 32 <10 <10 <10 <10 <10 <25 <25 <25 11 <10 <10 14 <10 <10 43 <25 <25 10 <10 <10 59 0 0 189 0 47 mean 12 19 11 11 <10 <10 <25 <10 <10 <25 <10 9 62 max 104 116 24 24 17 <10 <25 <10 14 40 4560 55 4696 Community C min median <10 12 <10 30 <10 <10 <10 <10 <10 <10 <10 <10 <25 <25 <10 <10 <10 <10 <25 <25 55 304 <10 <10 55 345 * Concentrations less than quantitation limits were considered as zero to calculate means and PFASs. mean 22 36 <10 <10 <10 <10 <25 <10 <10 <25 631 <10 710 ** Other PFECAs were present in water samples from community C but could not be quantified and were therefore not included in PFASs Sierra Club v. EPA 18cv3472 NDCA Tier 10 Page 6 of 12 ED 002061 00270551-00011 F, / OH PFMOAA / F /F PFMOBA y OH Y- OH PF02HxA FF FF W V ,o. / V. ,.OH / 'x -o-/ \ / YY \ / F FF FF PF04DA Figure SI. Molecular structures of PFECAs evaluated in this study Sierra Club v. EPA 18cv3472 NDCA Tier 10 Page 7 of 12 ED 002061 00270551-00012 Figure S2. Sampling sites in the Cape Fear River watershed, North Carolina. The scale is for the Cape Fear River watershed map. Sierra Club v. EPA 18cv3472 NDCA Tier 10 Page 8 of 12 ED 002061 00270551-00013 Concentration (ng/L) 1200 1000 800 600 400 200 0 - Concentration (ng/L) Sierra Club v. EPA 18cv3472 NDCA Tier 10 Page 9 of 12 ED 002061 00270551-00014 Figure S3. PFAS concentration distributions in the CFR watershed at three drinking water intakes. Concentrations less than quantitation limits were considered as zero. Upper and lower edges of a box represent the 75thand 25thpercentile, respectively; the middle line represents the median; upper and lower bars represent the 90thand 10thpercentile, respectively; and dots represent outliers (>90thor <10* percentile). Sierra Club v. EPA 18cv3472 NDCA Tier 10 Page 10 of 12 ED 002061 00270551-00015 2.56*0? 2.0E+0? 1.5 E+? * * # l. E + O ? * * 5 5.E+6 & y ".l Cofnmunity .. *--pOSnfiOW-- A | PFSs ! II A * W i l * . A MV 2500 2000 1500 | f 1000 w 500 .E4-00 .................................................................................................... 0 6/15/13 7/30/13 9/13/13 10/28/13 12/12/13 4,64-07 3.6407 * # Community 8 # Mean flow A J2 -4FfAaSssS 500 400 300 "Xd 2,5407 % S 1.6407 0,6400 6/15/13 7/30/13 -M 9/13/13 200 CL w 100 27 a - 0 10/28/13 12/12/13 6000 5000 V/ E 4000 g 3000 2000 4\i 1000 0 Figure S4. Total PFAS concentrations in the source water and stream flow at the three studied DWTPs. Stream flow data were acquired from US Geological Survey stream gage records Page 11 of 12 Sierra Club v. EPA 18cv3472 NDCA Tier 10 ED 002061 00270551-00016 100% a 1-30% 80% ,Oo'-- 60% ~!j PFN A - O P F D A --o --PFBS <>? ? K x $ ~*~PF0S -20% H-----------1---------- i---------- i---------- 1---------- :---------- 1---------- 1 0 20 40 60 80 100 120 140 ppm OPrA * time {min) PFM CBA PFPrOPrA ~0~ PF02H:<A O PF3A <> PF04DA 100% -i----------------------------------------------------------------------------- ; I d 80% "! --#- PFN A ~ O P F D A ~o~PF3S %>WPFHS ~&~PF0S "20% H------------(----------- !----------- !----------- !----------- !----------- :----------- i 0 20 40 60 80 100 120 140 time {min) -s^PFM OPrA HBhPFMOBA PFPrOPrA PF02HxA O PF030A -O -PF04D A PFN A ~0~PFDA ~o*~PFBS 'Ya -'PFHxS ~A-~PF$ TM *TM PFM 0PrA 0^PFO2HxA time {min) High PFM OBA -O PF030A PFPrOPrA PF04DA Figure S5. PFAS adsorption at powdered activated carbon doses of (a, b) 30 mg/L, (c, d) 60 mg/L and (e, f) 100 mg/L. Figures show average PFAS removal percentages of duplicate tests. Reference 1. Nakayama, S.; Strynar, M. J.; Helfant, L.; Egeghy, P.; Ye, X.; Lindstrom, A. B., Perfluorinated compounds in the Cape Fear drainage basin in North Carolina. Environ. Sci. Technol. 2007,41, (15), 5271-5276. Page 12 of 12 Sierra Club v. EPA 18cv3472 NDCA Tier 10 ED 002061 00270551-00017