Fluorotelomer Alcohol BiodegradationDirect Evidence that Perfluorinated Carbon Chains Breakdown

• Published in: Environmental science & technology Vol. 39; no. 19; pp. 7516 - 7528
• Main Authors: Wang, Ning, Szostek, Bogdan, Buck, Robert C, Folsom, Patrick W, Sulecki, Lisa M, Capka, Vladimir, Berti, William R, Gannon, John T
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.10.2005
• Subjects: Acids; Adsorption; Air flow; Alcohols - metabolism; Applied sciences; Bacteria - metabolism; Biodegradation; Biodegradation, Environmental; Biological and medical sciences; Biological treatment of waters; Biotechnology; Carbon; Carbon Dioxide - analysis; Carbon Radioisotopes - metabolism; Chlorofluorocarbons; Chromatography, Liquid; Environment and pollution; Exact sciences and technology; Fluorocarbons - metabolism; Fundamental and applied biological sciences. Psychology; General purification processes; Industrial applications and implications. Economical aspects; Kinetics; Mass Spectrometry; Metabolites; Mineralization; Pollution; Sewage - analysis; Sewage - microbiology; Sludge; Wastewaters; Water treatment; Water treatment and pollution; Water treatment plants; Biodegradation; Microbial activity; Activated sludge; Dehalogenation; Metabolite; Mixed microorganism culture; Alcohol; Telomere; Defluorination; Biological purification; Adsorption; Mineralization; Biotransformation; Qualitative analysis; Fluorine Organic compounds; Waste water purification; Degradation product; Organic compounds; Quantitative analysis
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es0506760

There is increasing scientific interest to understand the environmental fate of fluorotelomer alcohols (FTOHs) and fluorotelomer-based products which may break down to FTOHs. Both are expected to enter aqueous waste streams, which would be processed in a wastewater treatment plant and therein subject to microbial biodegradation. We investigated the biodegradation of 3-14C, 1H,1H,2H,2H-perfluorodecanol [CF3(CF2)6 14CF2CH2CH2OH, 14C-8-2 FTOH] in mixed bacterial culture and activated sludge. 14CO2 and 14C-organic volatiles in the headspace of the sealed bottles and bottles with continuous air flow were analyzed up to 4 months. After sample extraction with acetonitrile, 14C-labeled biotransformation products (metabolites) were quantified by LC/ARC (on-line liquid chromatography/accurate radioisotope counting) and identified by quadrupole time-of-flight (Q-TOF) mass spectrometry and GC/MSD (mass selective detector). Three metabolites not yet reported in the literature have been identified as CF3(CF2)6- 14CHOHCH3 (7-2 sFTOH), CF3(CF2)6 14CHCHCOOH (7-3 unsaturated acid or 7-3 u acid), and CF3(CF2)6 14CHCHCONH2 (7-3 u amide) along with five previously reported metabolites [CF3(CF2)6 14CF2CH2CHO (8-2 FTAL), CF3(CF2)6- 14CF2CH2COOH (8-2 acid), CF3(CF2)6 14CFCHCOOH (8-2 u acid), CF3(CF2)6 14CH2CH2COOH (7-3 acid), and CF3(CF2)6 14COOH (PFOA)]. No CF3(CF2)6 14CF2COOH (14C-PFNA) was observed, indicating that α-oxidation does not take place. It was found that strong adsorption to the activated sludge and subsequent transformation, even under continuous air flow, greatly reduced partitioning of 8-2 FTOH or any transformation products to air. CF3(CF2)4COOH (PFHA; perfluorohexanoic acid) was observed and increased in mixed bacterial culture over 28 days and accounted for about 1% of the initial 14C-8-2 FTOH concentration from day 28 to day 90. 14CO2 accounted for 1% of initial 14C in activated sludge with continuous air flow at day 1 and increased over time. In closed bottles, 14CO2 in the headspace of activated sludge medium increased to 12% of the available 14C over 135 days with periodic addition of ethanol, as compared to 3% when no additional ethanol was added. These results show that replenishment of organic carbon enhanced microbial mineralization of multiple −CF2− groups in the fluorocarbon chain of 14C-8-2 FTOH. At day 90 the net increase of fluoride ion in the mixed bacterial culture was 93 μg L-1, equivalent to 12% of total mineralization (destruction) of the 14C-8-2 FTOH. These results demonstrate that perfluorinated carbon bonds of 14C-8-2 FTOH are defluorinated and mineralized by microorganisms under conditions which may occur in a wastewater treatment plant, forming shorter fluorinated carbon metabolites.