Poly- and perfluorinated alkyl substances (PFASs) have contaminated the Tennessee river downstream of manufacturing facilities in Decatur, Alabama for over a decade. Manufacture and use of certain PFASs of high concern has ceased but little is known about replacement products or byproducts that may be present in the waste stream from these facilities. High resolution mass spectrometry was used to investigate the occurrence and identity of unknown fluorinated compounds in surface water and sediment downstream of these facilities. Analysis of legacy PFASs revealed a marked increase in concentrations downstream of the manufacturing facilities, with the most abundant compounds being perfluorooctane sulfonate (PFOS), perfluorobutane sulfonate (PFBS), and perfluorooctanoic acid (PFOA). Several unknown peaks appearing downstream but not upstream from the manufacturing facilities were investigated. A homologous series of nine polyfluorinated carboxylic acids was discovered, each differing by CF2CH2. Given that 1,1-difluoroethene is registered to a manufacturing facility in the area, it is hypothesized that these acids are byproducts of the manufacture of polyvinylidene fluoride (PVDF). Two additional predominant compounds have molecular formulas consistent with perfluorobutane sulfonate and perfluoroheptanoic acid but have a single hydrogen substituted for a fluorine someplace in their structure. A sulfate with differing mixes of hydrogen and fluorine substitution on the carbon atoms was also observed. The known but not well studied compound, N-methyl perfluorobutane sulfonamido acetic acid (MeFBSAA), was observed at high concentrations and several other perfluorobutane sulfonamides were present as well, suggesting that the previous mix of perfluorooctane sulfonamides may have been replaced with similar compounds. The drinking water intake for the West Morgan-East Lawrence drinking water facility is downstream of the manufacturing facilities in Decatur and has a history of PFAS contamination. Follow up efforts are underway to investigate these compounds in drinking water and serum of the population of northern Alabama.

Identification of novel polyfluorinated compounds in the Tennessee River downstream of manufacturing facilities near Decatur, Alabama, USA

254th National Meeting (2017)

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