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Home My WebLink About2020.12.31_CCO.p11a_PFAS Non-Targeted Analysis and Methods - Interim Report The Chemours Company Fayetteville Works 22828 NC Highway 87 W Fayetteville, NC 28306 PFAS NON-TARGETED ANALYSIS AND METHODS INTERIM REPORT #2 Process and Non-Process Wastewater and Stormwater Prepared by The Chemours Company FC, LLC Fayetteville Works 22828 NC Highway 87 W Fayetteville, NC 28306 December 31, 2020 The Chemours Company Fayetteville Works 22828 NC Highway 87 W Fayetteville, NC 28306 ii 31-Dec-2020 TABLE OF CONTENTS 1 INTRODUCTION ................................................................................................ 4 2 METHODS ........................................................................................................... 5 2.1 Sample Collection ........................................................................................ 5 2.2 Sample Preparation and Analysis ................................................................ 5 3 RESULTS ............................................................................................................. 5 3.1 General Facility Discharge Samples ............................................................ 5 3.2 Chemours Process Wastewater Samples ..................................................... 6 4 DISCUSSION AND NEXT STEPS ..................................................................... 6 4.1 General Facility Discharge Samples ............................................................ 7 4.2 Chemours Process Wastewater Samples ..................................................... 7 5 REFERENCES ..................................................................................................... 7 The Chemours Company Fayetteville Works 22828 NC Highway 87 W Fayetteville, NC 28306 iii 31-Dec-2020 LIST OF TABLES Table 1: Interim Report #2 - Status of 10 Unknown PFAS LIST OF FIGURES Figure 1: Site Location Figure 2: Sample Locations ACRONYMS AND ABBREVIATIONS CFRW – Cape Fear River Watch DEQ – Department of Environmental Quality LC – liquid chromatograph MS-MS – tandem mass spectrometry NCCW – non-contact cooling water PFAS – per- and polyfluoroalkyl substances Q-TOF-MS – quadrupole time of flight mass spectrometry The Chemours Company Fayetteville Works 22828 NC Highway 87 W Fayetteville, NC 28306 4 31-Dec-2020 1 INTRODUCTION This interim report has been prepared by The Chemours Company FC, LLC (Chemours) to provide an update on the characterization of previously unidentified per- and polyfluoroalkyl substances (PFAS) in aqueous samples collected from process wastewater, non-process wastewater (i.e., non- contact cooling water [NCCW]) and stormwater at the Chemours Fayetteville Works, North Carolina site (the Facility; Figure 1). This work is being conducted pursuant to Paragraph 11 subpart (a) in the Consent Order executed 25 February 2019 between Chemours and the North Carolina Department of Environmental Quality (DEQ) with the Cape Fear River Watch (CFRW) as intervenor. The overall purpose of this program is to identify previously unknown PFAS that may be present in samples of collected water and to develop standards and methods to facilitate the quantitative analysis of these PFAS, as described in the PFAS Non-Targeted Analysis and Methods Development Plan, Version 2 (the Development Plan; Chemours and Geosyntec, 2019) and the June 30, 2020 PFAS Non-Targeted Analysis and Methods Interim Report (Chemours, June 2020). This is the second interim report for the program. In the first interim report (Chemours, June 2020), the 5 most abundant unknown PFAS from General Facility Discharge samples (samples of stormwater, treated non-Chemours process wastewater and/or non-contact cooling water discharging to the Cape Fear River) and in Chemours Process Wastewater samples (samples of process wastewater from Chemours manufacturing areas) were proposed to be advanced to the next step in the program (identifying molecular structures). This second interim report provides an update on this step. The 5 most abundant unknown PFAS in the General Facility Discharge samples were identified as: • C4H5F3O2 • C4H2F4O2 • C6H6F6O2 • C8H7F9O2 • C10H8F12O2 The 5 most abundant unknown PFAS in the Chemours Process Wastewater samples were identified as: • C8H2F14O7S • C8HF13O4 • C8H5F13O6S • C9H2F14O6 • C6HF11O4 The Chemours Company Fayetteville Works 22828 NC Highway 87 W Fayetteville, NC 28306 5 31-Dec-2020 Of note, none of the identified 5 potential PFAS compounds in the General Facility Discharge samples were represented in the 5 potential PFAS compounds in the Chemours Process Wastewater samples. The remainder of this report consists of: • Section 2: Methods; • Section 3: Results; and • Section 4: Discussion and Next Steps. 2 METHODS 2.1 Sample Collection Samples were collected from 7 locations (Figure 2). Five sampling locations (Locations 4, 8, 9, 20 and 42) represent a combination of stormwater, treated non-Chemours process wastewater and/or non-contact cooling water. Two locations (16 and 17B) represent Chemours process wastewater. Some locations were sampled more than once; a total of 18 samples were collected. Samples were collected according to the methods outlined in the May 2019 PFAS Characterization Sampling Plan (Geosyntec, 2019) along with modifications to the sampling program to collect stormwater samples as outlined in Version 2 of the PFAS Non-Targeted Analysis and Method Development Plan (Chemours, 2019). Samples from locations 4, 9 and 42 were stormwater samples, and were collected during rain events. 2.2 Sample Preparation and Analysis Samples were prepared for non-targeted analysis by filtration through a 0.2-micrometer filter and were not diluted. Following filtration, the samples were injected directly into the analytical instrument for analysis by liquid chromatography followed by Q-TOF-MS (Agilent). Structural information was deduced by fragmenting ions via tandem mass spectrometry. Candidate structures that fit the fragmentation requirements for a particular unknown PFAS were then constructed. 3 RESULTS 3.1 General Facility Discharge Samples Investigation into the 5 potential PFAS compounds in the General Facility Discharge samples showed that 4 of the compounds (C4H5F3O2, C6H6F6O2, C8H7F9O2 and C10H8F12O2) coeluted from the liquid chromatograph (LC). This result was not expected. These compounds as previously identified would have different chain lengths and were therefore expected to be chromatographically resolved. Examination of the empirical formulas shows that the four The Chemours Company Fayetteville Works 22828 NC Highway 87 W Fayetteville, NC 28306 6 31-Dec-2020 compounds are related by the fragment C2HF3, that is, the addition of that fragment to each compound generates the empirical formula of the following compound. Taken together, this information suggests that these 4 compounds may represent a single compound, C4H5F3O2, eluting from the LC which undergoes adduction1 of the C2HF3 fragment during the tandem mass spectrometry (MS-MS) step. The C4H5F3O2 itself may be generated from a reaction between C2HF3 and acetate (present in the LC eluent) in the MS. A structure for the single compound (C4H5F3O2) has not yet been identified. The fifth unknown PFAS in the General Facility Discharge samples, C4H2F4O2, was not present in the samples at high enough concentrations to analyze by MS-MS. 3.2 Chemours Process Wastewater Samples Investigation into the 5 potential PFAS compounds in the Chemours Process Wastewater samples identified the following: • C8H2F14O7S - the following structure has been determined for this unknown PFAS: o CF3-CF(COOH)-O-CF2-CF(CF3)-O-CF2-CF2-SO3H • C8HF13O4 - a structure has been tentatively identified for this unknown PFAS, however, background contamination in the samples has to date interfered with confirmation of the tentatively identified structure • C8H5F13O6S - the following structure has been determined for this unknown PFAS: o HO3S-CF2-CF2-O-CF(CF3)-CF2-O-CHF-CF2-OCH3 • C9H2F14O6 – the following structure has been tentatively determined for this unknown PFAS: o HOOC-CF2-CF2-O-CF(CF3)-CF2-O-CF(CF3)-COOH • C6HF11O4 - a structure has not yet been identified for this unknown PFAS. Background contamination in the samples has to date interfered with confirmation of the tentatively identified structure. These results are summarized in Table 1. 4 DISCUSSION AND NEXT STEPS The second part of the Development Plan, the Enhanced Assessment, calls for the development of tentative molecular structures and subsequent development of authentic standards (i.e. synthesis of samples of the compounds to facilitate traditional targeted analysis) for the highest priority non- targeted PFAS identified. A summary of the next steps for each of the 10 potential PFAS compounds discussed in this interim report is provided below and in Table 1. 1 Adduction is the process of the direct addition of two or more distinct molecules that result in a single reaction product referred to as an adduct which containing all atoms of the two initial reaction molecules. The Chemours Company Fayetteville Works 22828 NC Highway 87 W Fayetteville, NC 28306 7 31-Dec-2020 4.1 General Facility Discharge Samples The 4 compounds that co-eluted in this assessment will be further investigated to understand the relationship between them. Planned investigations are: • assessment of the presence of C2HF3 in the samples. The presence of C2HF3 would support the hypothesis that this group of four compounds represents only 1 compound; • addition of C2HF3 to PFAS-free water to see if C4H5F3O2, C6H6F6O2, C8H7F9O2 and C10H8F12O2 are produced; • perform the analysis using formate (a one-carbon molecule) instead of acetate (a two- carbon molecule) in the LC eluting solution. As noted above, C4H5F3O2 may be generated from a reaction between C2HF3 and acetate in the eluent. This hypothesis would be supported if C4H5F3O2 is not observed when formate is substituted for acetate. The fifth compound in the General Facility Discharge samples, C4H2F4O2, could not be further investigated because it was not present in the samples at high enough concentrations to analyze by MS-MS. Alternative sample preparation methods that can concentrate analytes will be investigated in order to prepare samples with sufficient concentration of this compound to undergo MS-MS analysis. 4.2 Chemours Process Wastewater Samples Authentic standard synthesis will be initiated for the 3 compounds for which structures have been identified (C8H2F14O7S and C9H2F14O6) or tentatively identified (C8H5F13O6S). Because contamination interfered with the analysis of the remaining 2 compounds (C8HF13O4 and C6HF11O4), sample cleanup will be initiated so that their structures may be identified. 5 REFERENCES Chemours, 2020. PFAS Non-Targeted Analysis and Methods Interim Report. June 30, 2020. Chemours and Geosyntec Consultants, 2019. PFAS Non-Targeted Analysis and Methods Development Plan. Version 2. December 5, 2019. Geosyntec Consultants, 2019. PFAS Characterization Sampling Plan. Chemours Fayetteville Works. May 1, 2019. TABLE 1INTERIM REPORT #2 - STATUS OF 10 UNKNOWN PFASChemours Fayetteville Works, North CarolinaSample SourceEmpirical FormulaMass(amu)Mass toCharge Ratio(m/z)Identified Structure Next StepsC4H5F3O2142.0241 141.0168Structure not yet identifiedConduct experiments to see if this is a reaction product of C2HF3 and acetateC4H2F4O2157.9983 156.9910Structure not yet identifiedConcentrate sample to obtain enough of this unknown to conduct MS-MSC6H6F6O2224.0272 223.0199Structure not yet identifiedConduct experiments to see if this is an adduct of C4H5F3O2 and C2HF3C8H7F9O2306.0302 305.0230Structure not yet identifiedConduct experiments to see if this is an adduct of C4H5F3O2 and (C2HF3)2C10H8F12O2388.0331 387.0258Structure not yet identifiedConduct experiments to see if this is an adduct of C4H5F3O2 and (C2HF3)3C8H2F14O7S507.9302 506.9229CF3-CF(COOH)-O-CF2-CF(CF3)-O-CF2-CF2-SO3HInitiate synthesis of authentic standardC8HF13O4407.9670 406.9598Structure tentatively identifiedClean up background contamination to aid in structure identificationC8H5F13O6S475.9587 474.9515Structure tentatively identified as:HO3S-CF2-CF2-O-CF(CF3)-CF2-O-CHF-CF2-OCH3Initiate synthesis of authentic standardC9H2F14O6471.9630 470.9556HOOC-CF2-CF2-O-CF(CF3)-CF2-O-CF(CF3)-COOHInitiate synthesis of authentic standardC6HF11O4345.9693 344.9620Structure not yet identifiedClean up background contamination to aid in structure identificationNotes:adduct - a product of a direct addition of two or more distinct molecules resulting in a single reaction product containing all atoms of all componentsamu - atomic mass unitsC - carbonF - fluorineH - hydrogenO - oxygenPFAS - per- and polyfluoroalkyl substancesS - sulfurGeneral Facility DischargeChemours Process Wastewater December 2020 Kuraray AmericaLeased Areas ChemoursPPA Area Chemours Monomers IXM Area WastewaterTreatmentPlant Dupont / DowLeased Area Chemours Former TeflonProduction Area Site Location Chemours Fayetteville Works, North Carolina Figure 1Raleigh 750 0 750375 Feet Path: E:\TR0726\Saved Keep\TR0726_SiteLocationRaleigh.mxd; JK; 12/18/2018December 2020Notes:Basemap Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community Legend Drainage Network Site Boundary Areas at Site Chemours Monomers IXM Area Chemours PPA Area Dupont / Dow Leased Area Chemours Former Teflon Production Area Kuraray America Leased Area Wastewater Treatment Plant ") ") ") Du Pon t A reaWoodLinedTrench Ope n Cha nn e l t o Ou tfal l 0 02 Co oli n g Wat er Ch a nn el Wastewater TreatmentPlant Discharge Cape Fear R iver 4* 8 9* 20 16 17B 42* Paragraph 11(a) Non-Targeted Analysis Sample Locations Chemours Fayetteville Works, North Carolina Figure 2Raleigh 500 0 500250 Feet ³ December 2020 Projection: NAD 1983 StatePlane North Carolina FIPS 3200 Feet; Units in Foot US Notes:*- Locations 4, 9, and 42 are collected during rain events only. Sample numbers 4, 8, 9, 16, 17B and 20 correspond to locations identified in the May 2019 PFAS Characterization Plan. Samplenumber 42 corresponds to the location identified in the September2019 Stormwater Grab Sampling Workplan. . Legend !(Temporal Composite Sample ")Grab Sample Sample Location Category Stormwater Ditch Types Wood Lined Trench Cooling Water Channel Open Channel to Outfall 002 Non-process wastewater DuPont Area Process wastewater Outfall 002 Wastewater Treatment Plant Discharge 17B 4*