A method for isomer profiling of perfluorinated compounds (PFCs) in water was developed and applied to quantitatively assess the contributions from electrochemical (ECF) and telomer manufacturing processes around source regions of North America, Asia, and Europe. With the exception of 3 sites in Japan, over 80% of total perfluorooctanoate (PFOA, C(7)F(15)COO(-)) was from ECF, with the balance attributable to strictly linear (presumably telomer) manufacturing source(s). Comparing PFOA isomer profiles in samples from China, with PFOA obtained from a local Chinese manufacturer, indicated <3% difference in overall branched isomer content; thus, exclusive contribution from local ECF production cannot be ruled out. In Tokyo Bay, ECF, linear-telomer, and isopropyl-telomer sources contributed to 33%, 53%, and 14% of total PFOA, respectively. Perfluorooctane sulfonate (PFOS, C(8)F(17)SO(3)(-)) isomer profiles were enriched in branched content (i.e., >50% branched) in the Mississippi River but in all other locations were similar or only slightly enriched in branched content relative to historical ECF PFOS. Isomer profiles of other PFCs are also reported. Overall, these data suggest that, with the exception of Tokyo Bay, ECF manufacturing has contributed to the bulk of contamination around these source regions, but other sources are significant, and remote sites should be monitored.
"The principal idea behind this source apportionment tool is that the two major synthesis routes to produce PFOA result in distinct profiles of branched and linear isomers. Provided that ocean water is the final reservoir of PFOA, isomer profiles in water samples from industrialized or remote regions can be used for tracking production sources (Benskin et al., 2010b, 2012a; Yu et al., 2013; Fang et al., 2014a, 2014b). Electrochemical fluorination (ECF), which results in a mixture of branched and linear isomers, was used to produce the majority of APFO in Europe and North America between 1951 and 2000 (Prevedouros et al., 2006). "
"PFCAs, such as perfluorohexanoate (PFHxA) and perfluoroheptanoate (PFHpA) have also been found to be bioaccumulative and persistent during natural degradation processes although their environmental risk is less than PFOA  . High concentrations of PFCAs caused by direct discharge of wastewater have been detected in the waters near concentrated facilities involved in production or use of PFCAs   . Therefore, it is very important to remove PFCAs from industrial wastewater before being discharged into aquatic environments. "
[Show abstract][Hide abstract] ABSTRACT: Perfluorooctanesulfonyl fluoride (PFOSF) washing wastewater contains high concentrations of perfluorinated carboxylates (PFCAs) including perfluorohexanoate (PFHxA, 0.10 mmol/L), perfluoroheptanoate (PFHpA, 0.11 mmol/L), and perfluorooctanoate (PFOA, 0.29 mmol/L). For the first time, we investigated the removal of these PFCAs from actual wastewater using the bamboo-derived activated carbon (BAC) and resin IRA67. Adsorption kinetics, effects of adsorbent dose, solution pH, and inorganic ions, as well as regeneration and reuse experiments were studied. The removal percents of three PFCAs by BAC and IRA67 followed the increasing order of PFHxA < PFHpA < PFOA, but the adsorption equilibrium time conformed to the reverse trend. PFCAs removal on IRA67 decreased with increasing pH, but BAC almost kept stable PFCAs removal at pH above 5.0. Among competitive adsorption of three PFCAs, PFOA was preferentially adsorbed on both BAC and IRA67. PFCAs removal from actual wastewater by BAC was higher than that in simulated solution, due to the presence of high concentration of inorganic ions in the wastewater. However, the co-existing organic compounds in wastewater significantly suppressed the adsorption of PFCAs. Both spent BAC and IRA67 were successfully regenerated by ethanol solution or NaCl/methanol mixture, and IRA67 showed the stable removal of PFCAs in five adsorption cycles.
"However, there are several studies on the PFOS isomer profiles in surface water and groundwater, which are sources of drinking water. Enrichment of Br-PFOS relative to that of ECF-PFOS has been found in Lake Ontario (Houde et al., 2008), Mississippi River (Benskin et al., 2010), Taihu Lake (Yu et al., 2013), and groundwater in the watershed of River Rhine (Eschauzier et al., 2010). Our previous study found marked differences in the PFOS isomer profiles of Taihu Lake and Huai River, which are both in Jiangsu Province (Yu et al., 2013). "
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