Aerobic Biotransformation of 14C-Labeled 8-2 Telomer B Alcohol by Activated Sludge from a Domestic Sewage Treatment Plant
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- 作者：Ning Wang ; Bogdan Szostek ; Patrick W. Folsom ; Lisa M. Sulecki ; Vladimir Capka ; Robert C. Buck ; William R. Berti ; and John T. Gannon
- 刊名：Environmental Science & Technology
- 出版年：2005
- 出版时间：January 15, 2005
- 年：2005
- 卷：39
- 期：2
- 页码：531 - 538
- 全文大小：168K
- 年卷期：v.39,no.2(January 15, 2005)
- ISSN：1520-5851
文摘
This study investigated the biodegradation potential of3-14C,1H,1H,2H,2H-perfluorodecanol [CF3(CF2)614CF2CH2CH2OH, 14C-labeled 8-2 telomer B alcohol or 14C-labeled 8-2TBA] by diluted activated sludge from a domestic wastewatertreatment plant under aerobic conditions. After sampleextraction with acetonitrile, biotransformation products wereseparated and quantified by LC/ARC (on-line liquidchromatography/accurate radioisotope counting) with alimit of quantification about 0.5% of the 14C counts appliedto the test systems. Identification of biotransformationproducts was performed by quadrupole time-of-flight massspectrometry. Three transformation products have beenidentified: CF3(CF2)614CF2CH2COOH (8-2 saturated acid); CF3(CF2)614CF=CHCOOH (8-2 unsaturated acid); and CF3(CF2)614COOH (perfluorooctanoic acid, PFOA), representing 27,6.0, and 2.1% of the initial 14C mass (14C counts applied) after28 days, respectively. A transformation product, not yetreported in the literature, has also been observed andtentatively identified as CF3(CF2)614CH2CH2COOH (2H,2H,3H,3H-perfluorodecanoic acid); it accounted for 2.3% of themass balance after 28 days. The 2H,2H,3H,3H-perfluorodecanoic acid is likely a substrate for 
-oxidation, whichrepresents one of the possible pathways for 8-2 telomerB alcohol degradation. The 8-2 saturated acid and 8-2unsaturated acid cannot be directly used as substratesfor -oxidation due to the proton deficiency in their -carbon(C3 carbon) and their further catabolism may be catalyzedby some other still unknown mechanisms. The 2H,2H,3H,3H-perfluorodecanoic acid may originate either from the majortransformation product CF3(CF2)614CF2CH2COOH or fromother unidentified transformation products via multiple steps.Approximately 57% of the starting material remainedunchanged after 28 days, likely due to its strong adsorptionto the PTFE (poly(tetrafluoroethylene)) septa of the testvessels. No CF3(CF2)614CF2COOH (perfluorononanoic acid)was observed, indicating that 
-oxidation of CF3(CF2)614CF2CH2COOH did not occur under the study conditions.Several 14C-labeled transformation products that have notyet been identified (each less than 1% of the massbalance) were also observed and together accounted for7% of the total 14C mass balance after 28 days. It is notclear whether these unidentified transformation productswere resulting from further metabolism of 8-2 saturated acidor 8-2 unsaturated acid. The results suggest thatperfluorinated acid metabolites such as perfluorooctanoicacid account for only a very small portion of thetransformation products observed. Also, the observedvolatility and bioavailability of 14C-labeled 8-2 TBA for microbialdegradation was markedly decreased as a result of thepresence of a strongly adsorbing matrix such as PTFE inthe experimental systems. It is apparent that the biologicalfate of 8-2 telomer B alcohol is determined by multipledegradation pathways, with neither -oxidation nor anyother enzyme-catalyzed reactions as a single dominant(principal) mechanism under the study conditions.
-oxidation, whichrepresents one of the possible pathways for 8-2 telomerB alcohol degradation. The 8-2 saturated acid and 8-2unsaturated acid cannot be directly used as substratesfor -oxidation due to the proton deficiency in their -carbon(C3 carbon) and their further catabolism may be catalyzedby some other still unknown mechanisms. The 2H,2H,3H,3H-perfluorodecanoic acid may originate either from the majortransformation product CF3(CF2)614CF2CH2COOH or fromother unidentified transformation products via multiple steps.Approximately 57% of the starting material remainedunchanged after 28 days, likely due to its strong adsorptionto the PTFE (poly(tetrafluoroethylene)) septa of the testvessels. No CF3(CF2)614CF2COOH (perfluorononanoic acid)was observed, indicating that -oxidation of CF3(CF2)614CF2CH2COOH did not occur under the study conditions.Several 14C-labeled transformation products that have notyet been identified (each less than 1% of the massbalance) were also observed and together accounted for7% of the total 14C mass balance after 28 days. It is notclear whether these unidentified transformation productswere resulting from further metabolism of 8-2 saturated acidor 8-2 unsaturated acid. The results suggest thatperfluorinated acid metabolites such as perfluorooctanoicacid account for only a very small portion of thetransformation products observed. Also, the observedvolatility and bioavailability of 14C-labeled 8-2 TBA for microbialdegradation was markedly decreased as a result of thepresence of a strongly adsorbing matrix such as PTFE inthe experimental systems. It is apparent that the biologicalfate of 8-2 telomer B alcohol is determined by multipledegradation pathways, with neither -oxidation nor anyother enzyme-catalyzed reactions as a single dominant(principal) mechanism under the study conditions.