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HomeMy WebLinkAbout2019.12.31_CCO.p16_ChemoursCorrectiveActionPlan-AppendixC TR0795 December 2019 APPENDIX C Kow, Koc and Mass Distribution Calculations TR0795 1 December 2019 APPENDIX C MEASURED KOW AND CALCULATED KOC FOR TABLE 3+ COMPOUNDS Laboratory studies were performed at Chemours Experimental Station in Wilmington, Delaware to determine Table 3+ PFAS octanol-water partition coefficients (Kow) using liquid chromatography elution times (OECD, 2014). In this method, Table 3+ PFAS partition between the mobile solvent phase and the hydrocarbon stationary phase as they are transported along the column by the mobile phase. Compounds elute in proportion to their hydrocarbon-water partition coefficient, with hydrophilic chemicals eluted earlier and lipophilic chemicals later. Kow is then estimated by determining the retention time for each compound in relation to reference compounds with known Kow values. Kow tests were conducted on an Agilent 1290 Infinity II HPLC with an Agilent 6470 triple quad with an AJS-ESI source as the detector in multiple reaction monitoring mode (MS/MS filtering). The analytical column was a Phenomenex Gemini reversed phase C18 column 100 x 3 mm, 3 um particle size with 110 A pore size and TMS endcapping. The column was maintained at 50° C +/- 0.1° C by the LC column compartment oven. Mobile phase flow was isocratic at 0.5 mL/min. Table 3+ were separated into 4 groups to facilitate separation under isocratic conditions: • Group 1 - MMF, DFSA, MTP, Byproduct 4, Byproduct 5, and R-EVE; • Group 2 - PPF Acid and PMPA; • Group 3 - PFMOAA, NVHOS, PFO2HxA, PEPA, PES, PFECA B, and PFO3A; and • Group 4 - By product 6, Hydro Eve, By product 2, PFECA G, PFO4DA, Byproduct 1, Eve Acid, and PFO5DoA. Mobile phases were prepared daily. Tests were conducted with different isocratic mobile phases methanol/water compositions for each group, and at two pH values (pH 5 [4.89 - 5.10] and pH 8 [8.10 – 8.29]) to span Site pH conditions. Mobile phases were buffered with 20 mM ammonium salt buffer (acetate for pH 5 and bicarbonate for pH 8). Analytes were prepared in a minimum of 90% mobile phase. The retention time is described by the capacity factor k: 𝑘𝑘=𝑡𝑡𝑅𝑅− 𝑡𝑡0𝑡𝑡𝑅𝑅 where tR is the retention time of the Table 3+ compound, and t0 is the average time a solvent molecule needs to pass through the column (the dead-time). Kow values for Table 3+ Corrective Action Plan Appendix C Measured Kow and Calculated Koc TR0795 2 December 2019 compounds were estimated by experimentally determining k and then calculating Kow using the following equation: 𝑙𝑙𝑙𝑙𝑙𝑙 𝐾𝐾𝑜𝑜𝑜𝑜=𝑎𝑎+𝑏𝑏 𝑥𝑥log𝑘𝑘 where a, b = linear regression coefficients were calculated with a linear regression curve of log Kow and k of 11 reference PFAS compounds of varying structures (Table C-1 and Figure C-1). For DFSA, MTP, PPF, and PFMOAA, tR was found to be less than t0, thus log Kow was estimated by extrapolation and extrapolated values are provided in parenthesis. A linear regression curve between log Kow and log Koc was then developed using 20 reference compounds with known log Kow and log Koc (Table C-2 and Figure C-2). Results of the log Kow and log Koc values for Table 3+ PFAS are provided in Table 3 of the main CAP text. Table C-1:Reference Compounds for Log Kow versus Retention Time Linear Regression Curve Acronym Name Formula CAS # Log Kow1 Perfluoroalkyl Ether Carboxylic Acids HFPO-DA 2,3,3,3-Tetrafluoro-2-(1,1,2,2,3,3,3- heptafluoropropoxy)-propionic acid C6HF11O3 13252-13-6 3.6 Perfluoroalkyl Carboxylic Acids PFBA Perfluoro-n-butanoic acid C4HF7O2 375-22-4 2.82 PFPeA Perfluoro-n-pentanoic acid C5HF9O2 2706-90-3 3.43 PFHxA Perfluoro-n-hexanoic acid C6HF11O2 307-24-4 4.06 PFHpA Perfluoro-n-heptanoic acid C7HF13O2 375-85-9 4.67 PFOA Perfluoro-n-octanoic acid C8HF15O2 335-67-1 5.3 PFNA Perfluoro-n-nonanoic acid C9HF17O2 375-95-1 5.92 Perfluoroalkyl Sulfonic Acids PFBS Perfluorobutanesulfonic acid C4HF9O3S 375-73-5 3.9 PFHxS Perfluorohexanesulphonic acid C6HF13O3S 355-46-4 5.17 PFOS Perfluorooctanesulfonic acid C8HF17O3S 1763-23-1 6.3 Fluorotelomer sulfonic acids (Polyfluorinated) 6:2 FTS Fluorotelomer sulfonate C8H5F13O3S 27619‐97‐2 4.44 1 HFPO-DA value from Hopkins et al, 2018. PFOS value from Zhao et al., 2016. All other values from Concawe, 2016. Corrective Action PlanAppendix CMeasured Kow and Calculated Koc TR0795 3 December 2019 Figure C-1: Linear Regression Curve for Log P (log Kow) vs Log k (represents the retention time)at pH 5.10 for Select Reference Compounds Figure C-2: Linear Regression Curve of Log Kow vs Log Koc for Reference PFAS Compounds y = 0.5643x -0.6833R² = 0.8801 0 0.5 1 1.5 2 2.5 3 3.5 4 0 1 2 3 4 5 6 7 8 9Log KocLog Kow Corrective Action Plan Appendix C Measured Kow and Calculated Koc TR0795 4 December 2019 Table C-2: Reference Compounds for Log Kow and Log Koc Linear Regression Curve Acronym Name Formula CAS # Log Kow1 Log KOC [L/kg]1 Perfluoroalkyl Carboxylates / Perfluoroalkyl Carboxylic Acids PFBA Perfluorobutanoic Acid C4HF7O2 375-22-4 2.82 1.88 PFPeA Perfluoropentanoic Acid C5HF9O2 2706-90-3 3.43 1.37 PFHxA Perfluorohexanoic Acid C6HF11O2 307-24-4 4.06 1.91 PFHpA Perfluoroheptanoic Acid C7HF13O2 375-85-9 4.67 2.19 PFOA Perfluorooctanoic Acid C8HF15O2 335-67-1 5.3 2.35 PFNA Perfluorononanoic Acid C9HF17O2 375-95-1 5.92 2.39 PFDA Perfluorodecanoic Acid C10HF19O2 335-76-2 6.5 2.76 PFUnA Perfluoroundecanoic Acid C11HF21O2 2058-94-8 7.15 3.3 Perfluoroalkyl Sulfonates / Perfluoroalkyl Sulfonic Acids PFBS Perfluorobutane Sulfonate C4HF9O3S 375-73-5 3.9 1 PFHxS Perfluorohexane Sulfonate C6HF13O3S 432-50-8 5.17 1.78 PFOS Perfluorooctane Sulfonate C8HF17O3S 1763-23-1 6.3 3 PFDS Perfluorodecane Sulfonate C10HF21O3S 333-77-3 7.66 3.53 Perfluoroctane Sulfonamide and Derivatives N-MeFOSA N-Methyl-Perfluorooctane Sulfonamide C₉H₄F₁₇NO₂S 31506-32-8 6.07 3.14 N-EtFOSA N-Ethyl-Perfluorooctane Sulfonamide C₁₀H₆F₁₇NO₂S 4151-50-2 6.71 3.23 Perfluoroalkyl Ether Carboxylic Acids HFPO-DA Hexafluoropropylene oxide dimer acid C6HF11O3 13252-13- 6 3.21 1.1 Fluorotelomer Alcohols 4:2 FTOH Perfluorethylethanol 4:2 C₆H₅F₉O 2043-47-2 3.3 0.93 6:2 FTOH Perfluorhexylethanol 6:2 C8H5F13O 647-42-7 4.54 2.43 (8:2 FTOH) Perfluorocylethanol 8:2 C10H5F17O 865-86-1 5.58 3.84 (10:2 FTOH) Perfluordecylethanol 10:2 C12H5F21O 678-39-8 6.63 6.2 Fluorotelomer sulfonic acids (8:2 FTS) 1H, 1H, 2H, 2H-Per-fluorodecanesulfonic Acid C10H5O3F17S 39108-34-4 5.66 0.01 1 PFOS values from NGWA, 2019. HFPO-DA value from Hopkins et al., Recently Detected Drinking Water Contaminants: GenX and Other Per- and Polyfluoroalkyl Ether Acids, 2018. All other values from: Concawe. Environmental fate and effects of poly and perfluoroalkyl substances (PFAS), 2011. Compounds in parentheses were excluded from linear regression curve due to values not being compatible with PFAS structure correlations Corrective Action Plan Appendix C Measured Kow and Calculated Koc TR0795 5 December 2019 MASS DISTRIBUTION CALCULATIONS FOR TABLE 3+ COMPOUNDS The total mass of PFAS in saturated aquifers was calculated by summing PFAS in groundwater and PFAS sorbed on soils. The PFAS sorbed on saturated soil was calculated by taking the groundwater concentrations from a groundwater sample for each PFAS to PFAS sorbed on 0.1 kg soil using median fraction organic carbon foc similar lithologic units and Koc values. For locations where foc wasn’t measured, a median foc value from all lithologic units was used. An analysis was performed to determine whether PFAS mass on and offsite was primarily associated with the unsaturated zone or the saturated zone. This analysis was conducted to help evaluate the potential relative benefit between corrective action for soils versus groundwater. The analysis was conducted by comparing the unsaturated zone total mass (mass in pore water and soil) to the saturated zone total mass (mass in groundwater and soil) for samples taken from the same location. Total mass was calculated for one cubic meter of material (unsaturated or saturated). The total Table 3+ PFAS mass in the unsaturated zone was estimated by summing the total Table 3+ PFAS mass measured in soil samples from the unsaturated zone (this is assumed to include both PFAS n the pore water and PFAS sorbed on the soil). The total Table 3+ PFAS mass in the saturated zone was calculated using groundwater data from samples representative of the saturated zone to estimate the total mass of PFAS in the soil from which the groundwater sample originated. Parameters used for the calculations were: • Measured fraction organic carbon (foc) - values used for foc were the median value for the lithological unit from which the groundwater sample was collected. Foc data are presented in the On and Offsite Assessment report (Geosyntec, 2019); • Calculated Koc values - provided earlier in this Appendix; • Dry bulk density of the subsurface material -1.602 kg/L was used for all lithological units; • Porosity – 40% was used for all lithological units. The total mass of PFAS in groundwater and the total mass of PFAS in the soil were then added together to calculate a total mass of PFAS in the saturated zone. For this exercise, non-detects were not included in any calculations. Corrective Action Plan Appendix C Measured Kow and Calculated Koc TR0795 6 December 2019 Results are provided in Table C-3. Results are shown in Figure 4 in the main CAP text. Table C-3: PFAS Mass Distribution Between Saturated and Unsaturated Zone Location ID Sample Date Onsite/Offsite Sample Type Aquifer Saturation Total Mass per Cubic Meter (kg/m3) Bladen-2S 8/27/2019 Offsite GW saturated 5.79E-08 Bladen-2S 8/16/2019 Offsite S unsaturated nd Bladen-3S 8/28/2019 Offsite GW saturated 5.24E-08 Bladen-3S 8/20/2019 Offsite S unsaturated nd Bladen-4S 8/28/2019 Offsite GW saturated 7.19E-09 Bladen-4S 8/21/2019 Offsite S unsaturated nd Cumberland-1S 9/16/2019 Offsite groundwater saturated 1.27E-08 Cumberland-1S 9/13/2019 Offsite soil unsaturated nd Cumberland-2S 9/16/2019 Offsite groundwater saturated 1.94E-08 Cumberland-2S 9/12/2019 Offsite soil unsaturated nd Cumberland-3S 9/16/2019 Offsite groundwater saturated 9.69E-08 Cumberland-3S 9/12/2019 Offsite soil unsaturated nd Cumberland-4S 9/16/2019 Offsite groundwater saturated 2.50E-07 Cumberland-4S 9/11/2019 Offsite soil unsaturated 5.13E-07 Cumberland-4S 9/11/2019 Offsite soil unsaturated 6.25E-07 Cumberland-5S 9/16/2019 Offsite groundwater saturated 1.50E-08 Cumberland-5S 9/11/2019 Offsite soil unsaturated nd PW-01 9/9/2019 Onsite groundwater saturated 2.53E-05 PW-01 9/9/2019 Onsite groundwater saturated 2.31E-05 PW-01 7/31/2019 Onsite soil unsaturated 1.92E-06 PW-01 7/30/2019 Onsite soil unsaturated 7.05E-06 PW-02 9/11/2019 Onsite groundwater saturated 6.31E-03 PW-02 9/11/2019 Onsite groundwater saturated 6.62E-03 PW-02 7/29/2019 Onsite soil unsaturated 2.40E-06 PW-03 9/11/2019 Onsite groundwater saturated 1.78E-04 PW-03 9/11/2019 Onsite groundwater saturated 1.52E-04 PW-03 7/23/2019 Onsite soil unsaturated 1.07E-05 PW-05 9/9/2019 On Site groundwater saturated 2.11E-06 PW-05 7/26/2019 On Site soil unsaturated 1.36E-06 PW-06 9/10/2019 On Site groundwater saturated 1.35E-06 PW-06 7/29/2019 On Site soil unsaturated nd Corrective Action Plan Appendix C Measured Kow and Calculated Koc TR0795 7 December 2019 Location ID Sample Date Onsite/Offsite Sample Type Aquifer Saturation Total Mass per Cubic Meter (kg/m3) PW-07 9/13/2019 Onsite groundwater saturated 2.08E-06 PW-07 9/13/2019 Onsite groundwater saturated 1.95E-06 PW-07 7/24/2019 Onsite soil unsaturated nd PW-07 7/24/2019 Onsite soil unsaturated nd PW-09 9/11/2019 Onsite groundwater saturated 1.31E-06 PW-09 9/11/2019 Onsite groundwater saturated 1.24E-06 PW-09 8/12/2019 Onsite soil unsaturated nd PW-09 8/12/2019 Onsite soil unsaturated nd PW-11 9/10/2019 Onsite groundwater saturated 2.23E-04 PW-11 9/10/2019 Onsite groundwater saturated 2.42E-04 PW-11 7/25/2019 Onsite soil unsaturated 9.94E-07 PW-12 9/11/2019 Onsite groundwater saturated 7.07E-09 PW-12 9/11/2019 Onsite groundwater saturated nd PW-12 7/31/2019 Onsite soil unsaturated 1.33E-06 PW-12 7/31/2019 Onsite soil unsaturated nd PW-13 9/10/2019 Onsite groundwater saturated nd PW-13 9/10/2019 Onsite groundwater saturated nd PW-13 8/21/2019 Onsite soil unsaturated nd Robeson-1S 9/12/2019 Offsite groundwater saturated 2.36E-08 Robeson-1S 9/9/2019 Offsite soil unsaturated nd Robeson-1S 9/9/2019 Offsite soil unsaturated nd Notes: nd – no Table 3+ compounds were detected REFERENCES Concawe. Environmental fate and effects of poly and perfluoroalkyl substances (PFAS), June 2016. Geosyntec, 2019. On and Offsite Assessment. September 30, 2019. Hopkins, Z. R., Sun, M., DeWitt, J. C., & Knappe, D. R., 2018. Recently detected drinking water contaminants: GenX and other per‐and polyfluoroalkyl ether acids. Journal‐ American Water Works Association, 110(7), 13-28. Corrective Action Plan Appendix C Measured Kow and Calculated Koc TR0795 8 December 2019 NGWA, 2018. “NGWA Releases Groundwater and PFAS: State of Knowledge and Practice” 23 July 2018 https://www.ngwa.org/publications-and- news/Newsroom/2018-press-releases/ngwa-releases-groundwater-and-pfas OECD, 2014, OECD Guidelines for Testing of Chemicals: Partition Coefficient (n- Octanol/Water), High Performance Liquid Chromatography (HPLC) Method Zhao, P., X. Xia, J. Dong, N. Xia, X. Jiang, Y. Li and Y., Zhu, 2016. "Short-and long-chain perfluoroalkyl substances in the water, suspended particulate matter, and surface sediment of a turbid river." Science of the Total Environment 568: 57-65.