Title: | Aerobic biotransformation and fate of N-ethyl perfluorooctane sulfonamidoethanol (N-EtFOSE) in activated sludge |
Author(s): | Rhoads KR; Janssen EM; Luthy RG; Criddle CS; |
Address: | "Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305, USA" |
ISSN/ISBN: | 0013-936X (Print) 0013-936X (Linking) |
Abstract: | "Processes affecting the fate of perfluorinated organics are of increasing concern due to the global dispersal, persistence, and bioaccumulation of these contaminants. The volatile compound N-ethyl perfluorooctane sulfonamidoethanol (N-EtFOSE) and its phosphate esters have been used in protective surface coatings. In this report, we describe the fate of N-EtFOSE in aerobic batch assays. These assays were performed using undiluted activated sludge in serum bottles that were sealed to prevent the escape of N-EtFOSE and volatile transformation products. Separate assays were performed with N-EtFOSE and reported transformation products. N-EtFOSE degraded to N-ethyl perfluorooctane sulfonamido acetic acid (N-EtFOSAA) with an observed first-order rate of 0.99 +/- 0.08 day(-1) and a pseudosecond order rate of 0.26 +/- 0.02 L/mg VSS day(-1). N-EtFOSAA underwent further transformation at a slower rate (0.093 +/- 0.012 day(-1)) to N-ethylperfluorooctane sulfonamide (N-EtFOSA). N-EtFOSA then transformed to perfluorooctane sulfonamide (FOSA). FOSA transformed to perfluorooctane sulfinate (PFOSI), and PFOSI transformed to perfluorooctane sulfonate (PFOS). Perfluorooctanoic acid (PFOA) was not detected as a transformation product of any compound. Using the measured rate of N-EtFOSE biotransformation and literature values for phase partitioning and mass transfer in aeration basins, we modeled the fate of N-EtFOSE in a typical activated sludge aeration basin open to the atmosphere. The model predicts that 76% of the N-EtFOSE is stripped into the atmosphere, 5% sorbs to waste solids, 13% undergoes transformation to N-EtFOSAA, and 6% is discharged in the wastewater effluent" |
Keywords: | "Aerobiosis Biotransformation Chromatography, High Pressure Liquid Environmental Pollutants/*metabolism Hydrocarbons, Fluorinated/*metabolism Kinetics *Sewage Sulfonamides/*metabolism Tandem Mass Spectrometry;" |
Notes: | "MedlineRhoads, Kurt R Janssen, Elisabeth M L Luthy, Richard G Criddle, Craig S eng Research Support, U.S. Gov't, Non-P.H.S. 2008/05/24 Environ Sci Technol. 2008 Apr 15; 42(8):2873-8. doi: 10.1021/es702866c" |