Occurrence and Mass Flows of Fluorochemicals in the Glatt Valley Watershed, Switzerland

Abstract

Fluorochemicals are persistent contaminants that are globally distributed in air, water, sediments, and biota. Wastewater treatment plants (WWTPs) play an important role in mitigating pollutant releases from municipalities to aquatic and terrestrial environments. However, because WWTPs are point sources of fluorochemicals, it is important to understand their contribution to fluorochemical burdens in the greater context of watersheds. To this end, over a 1 week period, the mass flows of 11 fluorochemicals from seven WWTPs that discharge effluent into the Glatt River in Switzerland were measured and compared to the measured mass flows within the Glatt River. Overall, the fluorochemicals were not removed efficiently during wastewater treatment. Effluents from WWTPs and Glatt River water were dominated by perfluorooctane sulfonate, which was detected in all samples, followed by perfluorohexane sulfonate and perfluorooctanoate. The mass flows of fluorochemicals emanating from WWTPs were found to be conserved within the 35 km Glatt River, which indicates that input from the WWTPs is additive and that removal within the Glatt River is not significant. Per capita discharges of fluorochemicals were calculated from the populations served by the WWTPs studied; the values determined also account for the fluorochemical content of Lake Greifen (Greifensee), which is a lake at the headwaters of the Glatt River that also receives treated wastewater.

Perfluoroalkyl substances (PFASs) in wastewater treatment plants and drinking water treatment plants: Removal efficiency and exposure risk

“…So far, several previous studies have reported the occurrence of PFASs, especially PFOA and PFOS in WWTPs and tap water globally (Ericson et al, 2008;Huset et al, 2008;Jin et al, 2009;Quiñones and Snyder, 2009;Quinete et al, 2009;Arvaniti et al, 2012;Zhang et al, 2013;Schwanz et al, 2016). However, very limited information is available for the various PFASs in DWTPs (Shivakoti et al, 2010;Takagi et al, 2011;Thompson et al, 2011;Eschauzier et al, 2012;Flores et al, 2013).…”

Occurrence and in-stream attenuation of wastewater-derived pharmaceuticals in Iberian rivers

“…Several studies have predicted the expected concentrations of pharmaceuticals in surface waters using estimates of mass loading, dilution and in-stream attenuation, here understood as the reduction of the concentration of pharmaceuticals along the river segment by processes different than dilution (Huset et al 2008;Alder et al 2010). Reliability of these models is however constrained by the high variability in chemical emissions from WWTPs and attenuation in surface waters (Pistocchi et al 2010).…”

Congener specific organic carbon normalized soil and sediment-water partitioning coefficients for the C1 through C8 perfluoroalkyl carboxylic and sulfonic acids

“…PFAs have also been studied in municipal wastewater treatment plants (WWTPs) [7,33,37,42,43,[48][49][50]64,69,80,[136][137][138][139][140][141] where sorption of contaminants to organic matter and settling with particulates in grit chambers, trickling filters, rotating biological contactors, and primary/secondary clarifiers, as well as sorption to activation carbon if this polishing step is present, is a major removal process from the final effluent stream. Although it has been previously noted that a means of estimating K oc values for the C 1 through C 8 PFAs would be valuable in better understanding PFA profiles within WWTPs, [137] the potential range of PFA precursors that are subject to biological and physicochemical degradation into PFAs (e.g., perfluoroalkyl sulfonamides, fluorotelomers, etc.)…”

“…Caution must also be exercised in neglecting sorption losses to sediments in riverine PFA mass balance studies, particularly where only PFAs are monitored in upstream and downstream waters and wastewater inputs and a mass balance is achieved, as has been previously done. [37] In these studies, PFA precursors could be degrading in situ within a particular stream reach as an additional (and unaccounted for) PFA input with fluxes that offset PFA losses to sediments.…”