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RECYCLED ^'"^ AR226-2684 05 AR226-2684 MK The miracles of science Study Title ADSORPTION-DESORPTION SCREENING STUDIES OF AMMONIUM PERFLUOROOCTANOATE Author William R. Berti Report Completed May 2000 Performing Laboratory E. I. du Font de Nemours and Company Environmental and Microbiological Sciences & Engineering Corporate Center for Engineering Research Central Research & Development Glasgow, Building 300, P.O. Box 6101 Newark, DE 19714-6101 Report No. EMSE-053-00 Page 1 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION DuPont EMSE Report No. 053-00 GENERAL INFORMATION Material Tested: Ammonium perfluorooctanoate Synonyms/Codes: APFO, C-8, FC-143 DuPont Notebook No.: E98312 Sponsor: Robert Pinchot E. I. du Font de Nemours and Company BARLML CRP-711/2210-B Study Initiated / Completed: September 1999 / May 2000 Page 2 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION DuPont EMSE Report No. 053-00 ADSORPTION-DESORPTION SCREENING STUDIES OF AMMONIUM PERFLUOROOCTANOATE SUMMARY Five of nine materials appeared to adsorb a significant amount (greater than 25% of APFO added) at one or more concentrations ofAPFO. For four of the five materials to which APFO significantly adsorbed, most of the adsorbed APFO appeared not to desorb after 2 washings at one or more concentrations of added APFO. Study Conducted by: Kristi Bamett Research Technician, EMS&E (date) Study Conducted by: Jack DeCarolis Staff Biologist, EMS&E (date) Study Conducted by: George Fisher Research Technician (date) Study Conducted by: Bogdan Szostek, Ph.D. Research Scientist, Haskell Lab (date) Report Prepared by: William R. Berti, Ph.D. Senior Research Biologist, EMS&E Page 3 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION (date) DuPont EMSE Report No. 053-00 INTRODUCTION AND PURPOSE APFO adsorption/desorption screening studies were performed on several test materials, including two clays, a washed sand, peat moss, and an agricultural soil from Delaware, USA. The adsorption/desorption screening studies were also performed using two surface soils and two sediments from the Ohio River collected in the vicinity of the DuPont Washington Works plant near Parkersburg, West Virginia. The adsorption/desorption procedure used in this study was adapted from a method developed by the Office of Prevention, Pesticides and Toxic Substances (OPPTS), United States Environmental Protection Agency for use in the testing of pesticides and toxic substances, and the development of test data (1). Our objectives were to develop an adsorption/desorption protocol and analytical procedure for APFO. As part of this objective, we screened a variety of test materials for their APFO adsorption/desorption characteristics. MATERIALS AND METHODS Test Materials The Kaolin (KGa-2) and Montmorillonite (SAz-1) are Clay Mineral Society "Source Clays" and were obtained from the curator of the sample collection in the Department of Geology at the University of Missouri, Columbia. Additional information on these and other Source Clays has been published (2). The Quikrete All-Purpose sand and Scotts sphagnum peat moss were purchased locally at a builders' supply store (Home Depot). The Sassafras soil is a surface (0 to 15 cm) soil collected from an agricultural field in Delaware, USA. The Garden Area soil and East Wood soil were surface soils collected from the DuPont Washington Works plant. The Upstream sediment was obtained from the bank of the Ohio River upstream of the DuPont Washington Works NPDES permitted outfall, and the Downstream sedment was from downstream of the outfall. The two soil and sediment sample from the vicinity Washington Works were collected in the fall of 1999. Physical and chemical properties of the less than 2-mm size fractions of the soils, sediments, clays, sand, and peat moss used in this study are listed in Tables 1 and 2. Except for the clays, all samples were screened through a 2-mm (10 mesh) stainless steel sieve in preparation for the absorption/desorption screening test. Furthermore, the sand was washed using DI water through 2 mm and 50-um stainless steel sieves. Material retained on the 50 urn sieve was used in the study. The sand, soils, and sediments used in the studies were air-dried prior to use in the studies. Data calculations, however, were based on oven-dry weights of the samples. Oven-dry weights were determined after drying a subsample of material in an oven at 105C for a minimum of 24 h. The pH of the sample were determined in a 1:1 test material to water. Percent organic matter was determined using the loss on ignition method. Screening Test: Adsorption Studies Page 4 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION DuPont EMSE Report No. 053-00 The adsorption test was performed in duplicate on each material. A blank containing 0.01M CaCIa solution with test materials and no APFO and a single control at each APFO concentration but no material were also included. Each material was equilibrated with the aqueous phase of a solution of the test chemical at 5.0,0.5 and 0.05 mg L"1. prepared in 0.01M CaCb Sterile 50 mL Coming polypropylene centrifuge tubes were used as the test vessels. One part air-dried material (4.0 g) was weighed and 5 part test solution (20 mL) was decanted into a centrifuge tube, except the control tube. The centrifuge tubes were secured on an end-over-end mixer and agitated at about 30 rpm for 24 hours. Samples were centrifaged for 20 minutes using a RT6000B Sorvall centrifuge at 4000 x g and then filtered through a 0.2 urn nylon syringe filter into a new centrifuge tube. The volume of aqueous supernatant was measured and refrigerated at about 5C until analyzed for the parent compound using an LC-MS. The blank and the control tubes were subjected to the same steps as the test systems, including filtering. Screening Test: Desorption Studies To each solid phase (pellet) was added a fresh volume of 0.01M CaCIa solution without the test chemical equal to that added in the adsorption test, 20 mL. The sample was mixed, centrifuged, filtered, stored, and analyses as was done in the adsorption studies. This desorption step was repeated a second time, resulting in two washings that were analyzed separately. Calculations Data calculations included: 1. The percent of APFO adsorbed, A: A == (G - Ce x Vo)/G x 100 = x/G x 100 2. The percent of APFO which is desorbed, D: D = [(Cl + C2)V - (Vo - V)Ce]/x x 100 3. The percent of APFO which is not desorbed, R: R = [G - (Ce + Cl + C2)V]/x x 100 4. The adsorption coefficient, K': K' = (x/m)/Ce 5. The adsorption coefficient calculated as a function of the organic carbon content of the test material, K'oc: K'oc = K (100/percent organic carbon) Where: 1. m = dry weight of soil employed (g) 2. Ce = concentration of APFO remaining in solution (V) in the adsorption step (ug L"') 3. Cl = concentration of APFO in solution in the first wash (ug L'1) 4. C2 = concentration of APFO in solution in the second wash (ug L'1) 5. Vo = original volume of solution employed (mL) 6. V = volume of solution obtained after the adsorption step (mL) Page 5 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION .ueous su "wi usis '{< DuPont EMSE Report No. 053-00 7. G = quantity of material recovered from the soilless control (u,g) RESULTS AND DISCUSSION Of the nine materials tested, five of them (peat moss. Upstream sediment. East Wood soil. Garden Area soil, and Kaolin Clay) exhibited significant adsorption (greater than 25% of APFO added) at one or more of the added concentrations ofAPFO. Peat moss alone, however, adsorbed a significant amount at all three concentrations of added APFO; 50, 500, and 5,000 u,g APFO/L. Kaolin clay adsorbed a significant amount ofAPFO at 500 and 5,000 ug APFO/L. The Garden Area soil collected at Washington Works also adsorbed significant amounts ofAPFO at 500 u,g APFO/L. Upstream sediments from the Ohio River and East Wood soil adsorbed a significant amount ofAPFO at 50 u.g APFO/L only. Sand, Montmorillonite clay. Downstream sediment, and Sassafras soil did not adsorb a significant amount ofAPFO at any concentration of the added APFO. Once adsorbed on peat moss, most of the APFO (>76%) did not desorb after two washings with a solution of 0.01 M CaCL;. For the Kaolin clay, most the APFO adsorbed when added at 5,000 ug APFO/L desorbed with washing (>60%). At APFO added at 500 u,g APFO/L, however, an average of 98% did not desorb from the Kaolin clay after two washings. The East Wood soil, which adsorbed 46% of the APFO added at 50 ug APFO/L desorbed only about 2%. For the Garden Area soil 57% of the APFO desorbed when adsorbed from the 500 ug APFO/L solution. No measurable desorption ofAPFO from the Upstream sediment after two washings was observed when the APFO was added at 50 ug APFO/L. Page 6 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION DuPont EMSE TABLE 1. ADSORPTION-DESORPTION SCREENING STUDIES OF AMMONIUM PERFLUOROOCT Physical properties of test materials. Test material Moisture contentf % Test Material Dry Wt., Sand Silt Clay m S % %% Organic Matter y - ";:..,'.. % Org Carb % Sand 0.24 4.0 100 0 0 ND N Peat moss 47 2.1 ND ND ND ND N Kaolin clay 0.78 4.0 0 0 100 ND N Montmorillonite 7.4 3.7 0 0 100 ND N Sassafrass soil 1.4 3.9 71 19 10 1 0. East Wood soil 14 Garden Area soil 9.4 Upstream sediment 13 Downstream sediment 9.0 3.5 45 40 15 1.6 0. 3.7 37 42 21 2.9 1 3.5 59 30 11 1.5 0. 3.7 69 21 10 0.6 0. t Based on drying at 105C for a minimum of 24 h. t Estimated from percent organic matter. ND is not determined. Page 7 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION TABLE 2. Chemical properties of test materials. DuFont EMSE Test material pHf CECf meq/lOOg Exchangeable cations, meq/100g Ca Ms Na K H Sand 6.6 ND^f ND ND ND ND ND Peat moss 3.7 ND ND ND ND ND ND Kaolin clay 3.8 3.3 ND ND ND ND ND Montmorillonite 7.6 120 ND ND ND ND ND Sassafrass soil 6.3 2.8 2.10 0.51 0.01 0.21 0.00 East Wood soil 5.6 Garden Area soil 4.7 Upstream sediment 7.1 Downstream 6.9 sediment 10 17.2 7.4 5.9 4.19 5.85 6.08 4.54 0.61 1.15 0.86 1.09 0.04 0.01 0.27 0.20 0.15 0.18 0.15 0.09 5.01 10.01 0.04 0.00 fl:! test material to water. %Cation Exchange Capacity. Exchangeable cations in milliequivalents/100 g test material determined by a modified ammonium acetate metho T(ND is not determined. Page 8 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION DuPont EMSE R TABLE 3. Absorption/desorption screening test data. Test material Nominal APFO concentration Original solution volume, Vo WL-1 mL Volume of solution after adsorption step, V mL APFO in solution after adsorption step, Ce WL-1 APFO in first wash, Cl HKL-1 Sand 0.00 0.05 0.5 5 20.0 20.0 20.0 20.0 18.0 2.79E+01 ND 18.0 1.39E+02 ND 18.0 4.98E+02 ND 18.0 3.80E+03 ND Peat moss 0.00 0.05 0.5 5 20.0 20.0 20.0 20.0 18.0 4.00E+01 O.OOE+00 18.0 7.98E+00 O.OOE+00 18.0 6.55E+01 4.07E+01 18.0 9.62E+02 5.87E+02 Kaolin clay 0.00 0.05 0.5 5 20.0 20.0 20.0 20.0 18.0 1.65E+00 O.OOE+00 18.0 3.83E+01 NA 18.0 3.27E+02 3.31E+01 18.0 3.02E+03 4.52E+02 Montmorillonite 0.00 0.05 0.5 5 20.0 20.0 20.0 20.0 18.0 4.45E+01 O.OOE+00 18.0 4.68E+01 ND 18.0 3.80E+02 6.25E+01 18.0 3.69E+03 ND Page 9 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION 18.0 DuFont EMSE TABLE 3 (cont'd) Test material Sassafrass soil Nominal APFO Original solution concentration volume, Vo Volume of solution after adsorption step, V ^L" mL mL 0.00 0.05 0.5 5 20.0 20.0 20.0 20.0 18.0 18.0 18.0 18.0 APFO in solution after adsorption step, Ce HgL-1 O.OOE+00 4.33E+01 4.35E+02 3.63E+03 APFO in firs wash,Cl HgL-1 ND ND ND ND East Wood soil 0.00 0.05 0.5 5 20.0 20.0 20.0 20.0 18.0 7.50E-02 O.OOE+00 18.0 1.18E+01 1.63E+00 17.8 3.98E+02 7.53E+01 18.0 4.78E+03 7.44E+02 Garden Area soil Upstream sediment 0.00 0.05 0.5 5 0 50 500 5000 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 18.0 18.0 18.5 17.0 ""18.0 ""'IP 18.5 18.0 1.15E+01 2.57E+01 2.76E+02 3.68E+03 O.OOE+00 1.59E+01 4.12E+02 4.36E+03 6.93E+00 1.24E+01 1.19E+02 1.09E+03 O.OOE+00 8.50E-01 7.11E+01 7.71E+02 Page 10 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION DuPont EMSE TABLE 3 (cont'd) Test material Nominal APFO concentration Original solution volume, Vo Volume of solution after adsorption step, V WL-1 mL mL APFO in solution after adsorption step, Ce MRL-1 APFO in fir wash,Cl WL-1 Downstream sediment 0 50 500 5000 20.0 20.0 20.0 20.0 18.5 18.0 18.0 17.8 O.OOE+00 1.99E+01 4.58E+02 5.54E+03 O.OOE+00 O.OOE+00 4.63E+01 5.72E+02 Sassafrass soil 0.00 0.05 0.5 5 20.0 20.0 20.0 20.0 18.5 18.5 19.0 16.3 O.OOE+00 2.04E+01 4.94E+02 5.25E+03 O.OOE+00 4.50E-01 5.32E+01 8.40E+02 Page 11 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION TABLE 4. Adsorption/desorption screening test calculations. DuPont EMSE R Test material Sand Peat moss Kaolin Clay Montmorillonite Sassafrass Soil APFO Adsorbed Nominal recovered from Material material Adsorbed Adsorption APFO concentration the soilless control, G Adsorbed, desorbed, material not coefficient, X x/m or Cs A D desorbed, R K' WL-' W 1-ig l^g/g % % % 0.00 0.05 0.5 5 0 -5.57E-01 -1.40E-01 0 ND 0.896 -1.88E+00 -4.71E-01 -210 ND 9.99 3.50E-02 8.77E-03 0 ND 83 6.96E+00 1.55E+00 7 ND ND -5.01E-03 ND -2.93E-03 ND 2.36E-05 ND 4.04E-04 0.00 0.05 0.5 5 0 0.896 9.99 83 -7.99E-01 7.37E-01 8.68E+00 6.38E+01 -3.77E-01 3.47E-01 4.09E+00 3.01E+01 #VALUE! 82 87 77 #VALUE! -2 12 23 #VALUE! 102 88 77 #VALUE! 4.36E-02 6.91E-02 3.28E-02 0.00 0.05 0.5 5 0 0.896 9.99 83 -3.30E-02 -8.31E-03 #VALUE! 0 1.30E-01 3.26E-02 15 ND 3.45E+00 8.68E-01 35 2 2.26E+01 5.70E+00 27 61 #VALUE! #VALUE! 98 39 #VALUE! 8.61E-04 2.71E-03 1.90E-03 0.00 0 -8.90E-01 -2.40E-01 #VALUE! #VALUE! #VALUE! #VALUE! 0.05 0.896 -3.90E-02 -1.05E-02 -4 #VALUE! #VALUE! -2.10E-04 0.5 9.99 2.38E+00 6.44E-01 24 21 79 1.70E-03 5 83 9.15E+00 2.47E+00 11 #VALUE! #VALUE! 6.75E-04 0.00 0.05 0.5 5 0 0.896 9.99 83 O.OOE+00 O.OOE+00 #VALUE! ND 2.95E-02 7.48E-03 3 ND 1.30E+00 3.28E-01 13 ND 1.04E+01 2.63E+00 12 ND ND #DIV/0! ND 1.76E-04 ND 7.70E-04 ND 7.26E-04 Page 12 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION TABLE 4 (cont'd) s .tg, DuFont EMSE R Test material East Wood Soil APFO recovered Nominal APFO from the soilless concentration control, G X HgL-' 1-ig Hg x/m or Cs fg/g Material Adsorbed, A % Adsorbed material desorbed, D % Adsorbed material not desorbed,R % Adsorpti coefficie K' 0.00 0.05 0.5 5 0 0.422 10.1 96.8 -1.50E-03 1.86E-01 2.14E+00 1.17E+00 -4.26E-04 6.35E-02 7.93E-01 1.12E+00 #DIV/0! 46 19 -6 #DIV/0! 2 29 162 #DIV/0! 87 39 -315 #DIV/0 5.39E-0 2.00E-0 2.34E-0 Garden Area Soil 0.00 0.05 0.5 5 0 0.422 10.1 96.8 -2.31E-01 -9.15E-02 4.58E+00 2.32E+01 -6.30E-02 -7.15E-03 1.30E+00 7.50E+00 #DIV/0! -18 44 18 -64 -2142 57 51 164 2726 34 9 -5.47E-0 -2.70E-0 4.72E-0 2.04E-0 Upstream Sediment 0 50 500 . 5000 0 0.422 10.1 96.8 O.OOE+00 1.05E-01 1.86E+00 9.52E+00 O.OOE+00 4.25E-02 6.27E-01 3.23E+00 #VALUE! 27 16 3 #VALUE! -11 56 84 #VALUE! 90 17 -82 #VALUE O.OOE+0 O.OOE+0 7.64E-0 Downstream Sediment 0 50 500 5000 0 0.422 10.1 96.8 O.OOE+00 2.35E-02 9.36E-01 -1.40E+01 O.OOE+00 2. HE-02 4.40E-01 -2.29E+00 #VALUE! 9 7 -23 #VALUE! -81 5 13 #VALUE! 100 34 259 #VALUE 1.15E-0 9.75E-0 -4. HE-0 Sassafrass Soil 0.00 0.05 0.5 5 0 0.422 10.1 96.8 O.OOE+00 1.35E-02 2.17E-01 -8.28E+00 O.OOE+00 1.46E-02 1.19E-01 1.20E+00 #VALUE! 6 0 -17 #VALUE! -44 180 -107 #VALUE! 84 -201 -2450 #VALUE 7.35E-0 2.43E-0 2.24E-0 t ND = Not determined. Page 13 of 16 -^ .iiii'i-.r'. i: CONTAINS CONFIDENTIA.fTcSlES-f^USINESS INFORMATION FIGURE 1. DuPont EMSE R I. M'-'. Adsorption isoline ofAPFO onto Sand, Peat moss, Kaolin clay, Montmorillonite clay, and Sassafras 0 1000 2000 3000 4000 5000 Ce, ug C-8 L-1 Page 14 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION DuPont EMSE R FIGURE 2: Adsorption isoline ofAPFO onto East Wood soil, Garden Area soil, Upstream sediment, and downs 0 1000 2000 3000 4000 5000 6000 Ce, ug C-8 L'1 Page 15 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION DuPont EMSE Report No. 053-00 Reference: 1 US EPA. 1998. Fate, transport and transformation test guidelines: OPPTS 835.1220 sediment and soil adsorption/desorption isotherm. United State Environmental Protection Agency Office of Prevention, Pesticides, and Toxic Substances. EPA712-C-98-048. January 1998 2 Olphen, H.V., and J.J. Fripiat (eds.). 1979. Data handbook for clay materials and other nonmetallic minerals Pergamon Press. New York 346 pp. Ijjl Page 16 of 16 CONTAINS CONFIDENTIAL BUSINESS INFORMATION