Document Zybn0JrZ13Bm2RKZL3mz9GzL

Biotransformation of ^C-Labeled Fluorotelomer Substances by Soil M Wane N,1, Szostek B.2, Buck R.C.3, Folsom P.W.1, Sulecki L.1, Powley C.2, Berti W.1, and Gannon J.T. 1 DuPont Central Research and Development, Newark, USA; 2 DuPont Haskell Laboratory; USA;3 DuPont Chemical Solu AR226-3364 Introduction Growing public interest in the environmental fate of fluorinated chemicals due to the global presence ofperfluorinated acids such as perfluorosulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). 8-2 TelomerB Alcohol (8-2 TBA, CP3(CF;,)(,CF:;CH:,CH20H) is a major raw material used in the manufacture of sales products (e.g. fluorosurfactants and fluoropolymers). The chain length, (CF^g, is representative of the telomer intermediates used to manufacture sales products. Physical Properties and Purity of the Test Substance - cVj(CV^ 'CF^CHiCH^OH "A Difficult-toTest Substance" Low solubility ~150ugL-' Vapor pressure 3 Pa at 21 C Adsorption to surfaces A Chromatogram ofHPLC Characterization of Radiochemical Purity of the Test Substance Virtually KKIVo purity Time (min) [FigureTJ Stud To answe Is 8-2 TBA readily tran What are the potential m What are the likely path Are alternative biotrans TBA beyond PFOA? Does microbial a-oxida perfluorononanoic acid Can 8-2 TBA and poten and thereby not bioavai Materials and Methods Sail: Sassafras soil - pH = 5.5, OM = 2.9%. Sandy loam, Microbial Biomass = 154.4 ug carbon /g dry soil. Sully Malarial: Custom synthesized "(-labeled 8-2 TBA (CFiCCF^^CFtCHaCH^OH) at~180|igiCg-isoil. Additional Carbon source: - 50 mg ethanol (as cosolvent) Kg -' soil. Experimental System: Closed bottles (10 g soil plus substance solution in 127-mL bottles). The experimental duration is up to one year and the 0; content and the respiration rate of the soil were monitored during the study. Extraction: 1: CH,CN (acetonilrile) at room T for several days; 2": 90% CH,CN + 20 mM NaOH at 50 C overnight. The 1" and 21'11extract solutions were analyzed separately by LC/ARC. Analysis: LC/ARC (On-Line Chromatograph/Accurate Radioisotope Counting) and quadrupole time of flight mass spectrometry (Q-TOF-MS) for "C-metabolite quantification and identification, and LC/MS/MS for PFHA [CPi(CF,).,COOH] quantification. "C-volatile trapping: 10 mL ofheadspace gas were passed through Two Cig. cartridges (0.6 g each) mounted in tandem to trap organic volatiles and the cartridges were eluted with 5 mL ofCHsCN. "CO, trapping: The headspace gas after passing through two C,g. cartridges was trapped in 5 mL of 1 N of NaOH. >* TABLE 1. LC/ABCptakumnbi r, acronym, structure, and molecular weight onhemetBbolltes of"C--2 TBA biodegradation LC/ARC Acronym Suucture PcakO^flnKh^ sinjcture datamihatlons Nlintet " I" '"I"" Molecuiar Mass CF)(CF^"COOH (PFOA) and an unknown CF,(CF^"CF=CFCH,COOH CF,(CF,),"CH,CH,COOH CF,(CFJ,"CF,CH,CH,OH (Parent) CF,(CPA"CP,CH,CHO ana/or CFi(CP^'*CF=CH3? CF,(CF,).COOH 8-2 imsaturaled ->^W- acid 2MH,2H,3H, > ^ y y ^ 3HH-.PPEHD,A ia y V Y y 1 44- -------- ^^<- acd'or 8-2 FT Olefin W- Results and P-'-'Cl-S^ TBA (peak 7) is tra - Over 90% of "C-8-2 TBA w observed were not volatile. PFOA, an unknown metabolit are the major metaboHtes at d 8-2 nnsaturated acid (peak 4) w Peak 6 is major metabolite fro Two unknown ;f-.-metabolites (retention time < PPOA), were - They may be possible interm Peak 8 was formed from day 1 - Transient intermediate(s) a No CF3(CF2),;"CF,COOH (PF - Microbial d-oridation of "C Results and Discussion - Figure 2 Results and Discussion Figure 2 LC/ARC Chromatograms of ^C-parent and metabolites Siabstandial "Seqpes^ratiea''1 Observed ^C-parent and metabolites are strongly adsorbed to the live soil, probably to (he soil organic matters, within 7 days. - After day 7, about 50% of the "'C-parent and metabolites became unrecoverable by conventional solvent extraction methods (CH3CN, ethanol, acetone, THF, or MTBE at 50C; CH3CN plus 1 M Nad, CH3CNpluslMHCl). - Only 0.5% triefhylamine and 0.020-1 M NaOH plus CH,CN at 50 C overnight gave a good recovery for samples between days 7-28. - After day 28, even 20 mM NaOH plus CH,CN at 50 C overnight can only gave a partial recovery of the "C from the soil. - Cobalt-60-sterilized, but not autoclaved soil, resulted in near complete recovery (even at day 84) of '"C-parent and fluorinated carboxylic acids spiked (dosed) into the soil at day 0. (CF3(CF^)CF2CH;,CH:,OH, CF3(CF2),,CP;,CH2COOH, CF3(CF2)5CF= CFCH;COOH, PFOA, and PFHA) Results and "CO; Retease: Evi 2% ^COz was detected in t the live soil sample bottles. Indicates that the fluorinate has been de-fluorinated and The loss of ^(.'-labeling sh metabolites with fluorocarb lessthan8- Possib : ^ CF Results and Discussion - Figure 4 SfciffiSi Aieohcl VolatlHty The volatility of "C-8-2 TBA once applied to the soil was minimal. - Only ~ 2% of "C was detected in the headspace over 45 days. - No additional ''\"containing organic volatiles were detected after day 24. Strong adsorption to the soil and rapid conversion to other non-volatile metabolites significantly decrease the potential for alcohol release to air from soil. Days after the initiation I Figure 4 ! Results and Discussion - Figure 5 PerfiuoroheiiariO!!; Acid Fortriation Oucfocs'boti Chain "OiigraA-rtton" ,14% of total mass balan; !CF3(CF^)6;<^:F-CH i^^^2H+-*-2e" y^ HF iCP^CP^'^H-CHai pL. ; '-*' CF)<CF Days after the initiation | Figure 5 | Conc [S-^C] - 8-2 TBA was rapidly transformed. PFOA, an unknown metabolite and 2H,2H,3H -- A substantial amount are strongly sorbed a No PFNA was observed. Minimal 8-2 TBA volatility was observed, Acid Metabolites identified are not expected transport. Significant '"^CO;;evolution and PFHA were - Indicate that biotransformation pathways in metabolites with less than eight fluorina