- Fluorinated alkyl substances, which can be persistent, toxic, and
bioaccumulative, have been quantitated in many densely populated and
remote regions, including in air, surface waters, groundwater, and biota;
however, little is known about their transport or behavior in the environment.
Wastewater effluent is one of the principal routes for introducing environmental
contaminants into aquatic environments. The partitioning behavior of
fluorinated alkyl substances between aqueous and particulate phases is not
well characterized; thus, sorption onto sludge can be a removal mechanism of
fluorinated alkyl substances from the wastewater stream. This is another
route into the environment if the biosolids are land-applied.
In an attempt to analyze for the fluorinated alkyl substances in
wastewater, known aqueous-film-forming-foam (AFFF)-laden groundwater
sampled from 3 military bases was used to develop an assay using liquid
chromatography (LC), electrospray ionization (ESI) tandem mass spectrometry (MS/MS). While working on the method development,
fluorotelomer sulfonates were detected at Wurtsmith AFB, MI, and Tyndall
AFB, FL, where total fluoroatkyl sulfonates ranged respectively from below
quantitation (≤0.60 μg/L) to 182 μg/L and from 1100 μg/L to 14,600 μg/L.
The LC ESI-MS/MS method was modified to quantitate fluorinated alkyl
sulfonates in wastewater by incorporating a htgh volume sample loop (500
μL), which lowered detection and quantitation limits by at least a factor of 50.
This method was applied to 24 h composites of influents and effluents
collected from treatment plants distributed nationwide. Fluorinated alkyl
substances were observed at all 10 plants sampled, and each wastewater
treatment plant was found to have a unique distribution of fluorinated alkyl
substances, despite similar treatment processes. In 9 out of the 10 plants
sampled, at least one class of fluorinated alkyl substance exhibited significant
increases in the effluent as compared to the influent levels.
The high-volume-injection LC ESI-MS/MS method was also used to
monitor the mass flows of perfluoroalkyl sulfonates and carboxylates through a
municipal wastewater treatment plant for 10 d. The perfluoroalkyl
carboxylates were overall removed by the wastewater treatment process (25-40% removal). Perfluoroalkyl sulfonates were found to increase significantly
(~200%) in the final effluent, and the fluoroalkyl sulfonamide acetic acids were
found to increase by approximately 500% throughout the sludge process.
From this plant, significant quantities of fluorochemicals are discharged with
treated wastewater and biosolids, indicating that wastewater treatment plants are point sources of fluorinated alkyl substances and must be considered
when determining origins and behavior of fluorinated alkyl substances in the