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Current studies suggest that perfluorinated organic compounds, such as fluorotelomer alcohols (FtOHs) in the troposphere, may be precursors of perfluorocarboxylic acids and perfluorosulfonates in remote regions. Fluorinated organic compounds were investigated in archived extracts collected from remote locations in Okinawa, Japan (HSO) and Mount Bachelor, Oregon (MBO) during the springs of 2004 (MBO and HSO) and 2006 (MBO only). These high volume air samples were subjected to pressurized liquid extraction, concentrated, and analyzed by GC/MS. FtOHs were measured in both HSO and MBO air masses, though MBO had significantly higher concentrations. We identified fluorotelomer olefins (in HSO air) and 8:2 fluorotelomer acrylate (in MBO 2006 air) for the first time in published literature. N-Ethyl perfluorooctane sulfonamide (N-EtFOSA), N-Methyl perfluorooctane sulfonamido ethanol (N-MeFOSE), and N-Ethyl perfluorooctane sulfonamido ethanol (N-EtFOSE) were measured in HSO and MBO air masses, but detected less frequently than FtOHs. 6:2 fluorotelomer acrylate, perfluorooctane sulfonamido acrylates, perfluorobutane sulfonamide, and perfluorobutane sulfonamido ethanol were not detected in any air samples from this study. For MBO 2006, the sources of fluorotelomer alcohols were investigated using HYSPLIT back trajectories, residual fluorinated product signatures, and correlations with semi-volatile organic compounds (SOCs). FtOH concentrations during MBO 2006 were not significantly correlated (p-value > 0.05) with the amount of time an air trajectory spent in a specific source region such as California, Washington, Oregon, and Canada. Since FtOH concentrations were significantly correlated (p-value < 0.05) with each other, the average ratio of 6:2 FtOH to 8:2 FtOH to 10:2 FtOH during MBO 2006 was calculated to be 1.0 (0.1) to 5.0 (0.7) to 2.5 (0.4), where the parenthesis represent 95% confidence intervals. Also, FtOH concentrations at MBO 2006 were positively correlated (p-value < 0.5) with gas-phase PAHs and PCBs and negatively correlated (p-value <0.05) with agricultural pesticides such as endosulfan. This suggests that FtOHs are coming mainly from urban sources. Atmospheric residence times from MBO 2006 data for 6:2 FtOH, 8:2 FtOH, and 10:2 FtOH, based on a method using trace gas variability, were calculated to be 50, 80, and 70 days, respectively. Finally, gas/particle partitioning of semi-volatile flurochemicals was examined. |
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