Abstract
The presence of unidentified organofluorine compounds (UOF) has been investigated in recent publication, but their environmental occurrence is still poorly understood. Fluorine mass balance analysis was performed on environmental samples from lake Mjøsa and river Alna (surface water (n = 9), sediment (n = 5) and fish liver (n = 4)) and sewage samples from Oslo (n = 5), to reveal to the fraction of UOF. In samples that had extractable organofluorine (EOF) concentrations above the limit of detection (LoD), more than 70% of their EOF could not be accounted for by the 37 PFAS monitored in this study. The surface water samples from lake Mjøsa had EOF concentrations several times higher than what has been reported elsewhere in Nordic nations. The flux of EOF in river Alna and selected sewage pipes revealed that it was 1-2 orders of magnitude higher than the flux of the measured PFAS. The elevated concentrations of EOF in all samples pose a potential health and environmental hazard, as their composition remains mostly unknown.
Highlights
Fluorine mass balance analysis has risen as a prospective technique for tackling the challenge of per- and polyfluoroalkyl substance (PFAS) analysis by combining target PFAS and extractable organofluorine (EOF) data
The reason for this is due to the large number of PFAS being used for various applications (Buck et al, 2011), with OECD identifying more than >5000 CAS numbers corresponding to PFAS (Toward A New Comprehensive Global Database Of Per- And Polyfluoroalkyl Substances (PFASs), 2018), while routine target analyses in national environmental monitoring programs often include only the most commonly used and identified, usually the C4–C15 perfluorinated carboxylic acids (PFCAs) and C4–C10 perfluorinated sulfonic acids (PFSAs) (US EPA, 2015; Apler and Josefsson, 2016)
These results have demonstrated that traditional target PFAS analysis is overlooking a significant portion of the organofluorines, both in human and environmental samples (Yeung and Mabury, 2016; Karrman et al, 2019; Miaz et al, 2020)
Summary
Fluorine mass balance analysis has risen as a prospective technique for tackling the challenge of per- and polyfluoroalkyl substance (PFAS) analysis by combining target PFAS and extractable organofluorine (EOF) data. To better understand the total amount of PFAS in environmental samples, analyses of EOF content may serve as an important metric alongside target analysis, total oxidizable precursor assay and non-target analysis This method was first applied to human blood and water samples by Miyake et al (Miyake et al, 2007a; Miyake et al, 2007b), and has been adopted for a range of environmental samples such as invertebrates (Koch et al, 2019), sediment (Yeung et al, 2013; Codling et al, 2014), surface water (Koch et al, 2019; D’Agostino and Mabury, 2017) and marine mammals (Spaan et al, 2020). These methods come with their own limitations, TOP assay assumes that the unidentified compounds can oxidize to measurable PFAAs (Houtz and Sedlak, 2012) and NTA provides only semi-quantitative results, which can lead to underestimation of the organofluorine content (Dubocq et al, 2020)
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