Fluorotelomer Alcohol Biodegradation-Direct Evidence that Perfluorinated Carbon Chains Breakdown
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- 作者：Ning Wang ; Bogdan Szostek ; Robert C. Buck ; Patrick W. Folsom ; Lisa M. Sulecki ; Vladimir Capka ; William R. Berti ; and John T. Gannon
- 刊名：Environmental Science & Technology
- 出版年：2005
- 出版时间：October 1, 2005
- 年：2005
- 卷：39
- 期：19
- 页码：7516 - 7528
- 全文大小：362K
- 年卷期：v.39,no.19(October 1, 2005)
- ISSN：1520-5851
文摘
There is increasing scientific interest to understand theenvironmental fate of fluorotelomer alcohols (FTOHs) andfluorotelomer-based products which may break downto FTOHs. Both are expected to enter aqueous wastestreams, which would be processed in a wastewater treatmentplant and therein subject to microbial biodegradation.We investigated the biodegradation of 3-14C, 1H,1H,2H,2H-perfluorodecanol [CF3(CF2)614CF2CH2CH2OH, 14C-8-2 FTOH]in mixed bacterial culture and activated sludge. 14CO2 and14C-organic volatiles in the headspace of the sealedbottles and bottles with continuous air flow were analyzedup to 4 months. After sample extraction with acetonitrile,14C-labeled biotransformation products (metabolites) werequantified by LC/ARC (on-line liquid chromatography/accurate radioisotope counting) and identified by quadrupoletime-of-flight (Q-TOF) mass spectrometry and GC/MSD(mass selective detector). Three metabolites not yet reportedin the literature have been identified as CF3(CF2)6-14CHOHCH3 (7-2 sFTOH), CF3(CF2)614CH=CHCOOH (7-3unsaturated acid or 7-3 u acid), and CF3(CF2)614CH=CHCONH2(7-3 u amide) along with five previously reportedmetabolites [CF3(CF2)614CF2CH2CHO (8-2 FTAL), CF3(CF2)6-14CF2CH2COOH (8-2 acid), CF3(CF2)614CF=CHCOOH (8-2 u acid),CF3(CF2)614CH2CH2COOH (7-3 acid), and CF3(CF2)614COOH(PFOA)]. No CF3(CF2)614CF2COOH (14C-PFNA) was observed,indicating that 
-oxidation does not take place. It wasfound that strong adsorption to the activated sludge andsubsequent transformation, even under continuous air flow,greatly reduced partitioning of 8-2 FTOH or any transformationproducts to air. CF3(CF2)4COOH (PFHA; perfluorohexanoicacid) was observed and increased in mixed bacterial cultureover 28 days and accounted for about 1% of the initial14C-8-2 FTOH concentration from day 28 to day 90. 14CO2accounted for 1% of initial 14C in activated sludge withcontinuous air flow at day 1 and increased over time. Inclosed bottles, 14CO2 in the headspace of activated sludgemedium increased to 12% of the available 14C over 135days with periodic addition of ethanol, as compared to 3%when no additional ethanol was added. These resultsshow that replenishment of organic carbon enhancedmicrobial mineralization of multiple -CF2- groups in thefluorocarbon chain of 14C-8-2 FTOH. At day 90 the net increaseof fluoride ion in the mixed bacterial culture was 93 
gL-1, equivalent to 12% of total mineralization (destruction)of the 14C-8-2 FTOH. These results demonstrate thatperfluorinated carbon bonds of 14C-8-2 FTOH are defluorinatedand mineralized by microorganisms under conditionswhich may occur in a wastewater treatment plant, formingshorter fluorinated carbon metabolites.
-oxidation does not take place. It wasfound that strong adsorption to the activated sludge andsubsequent transformation, even under continuous air flow,greatly reduced partitioning of 8-2 FTOH or any transformationproducts to air. CF3(CF2)4COOH (PFHA; perfluorohexanoicacid) was observed and increased in mixed bacterial cultureover 28 days and accounted for about 1% of the initial14C-8-2 FTOH concentration from day 28 to day 90. 14CO2accounted for 1% of initial 14C in activated sludge withcontinuous air flow at day 1 and increased over time. Inclosed bottles, 14CO2 in the headspace of activated sludgemedium increased to 12% of the available 14C over 135days with periodic addition of ethanol, as compared to 3%when no additional ethanol was added. These resultsshow that replenishment of organic carbon enhancedmicrobial mineralization of multiple -CF2- groups in thefluorocarbon chain of 14C-8-2 FTOH. At day 90 the net increaseof fluoride ion in the mixed bacterial culture was 93 gL-1, equivalent to 12% of total mineralization (destruction)of the 14C-8-2 FTOH. These results demonstrate thatperfluorinated carbon bonds of 14C-8-2 FTOH are defluorinatedand mineralized by microorganisms under conditionswhich may occur in a wastewater treatment plant, formingshorter fluorinated carbon metabolites.