Continuous non-marine inputs of per- and polyfluoroalkyl substances to the High Arctic: a multi-decadal temporal record

Abstract

Abstract. Perfluoroalkyl acids (PFAAs) are persistent, in some cases, bioaccumulative compounds found ubiquitously within the environment. They can be formed from the atmospheric oxidation of volatile precursor compounds and undergo long-range transport (LRT) through the atmosphere and ocean to remote locations. Ice caps preserve a temporal record of PFAA deposition making them useful in studying the atmospheric trends in LRT of PFAAs in polar or mountainous regions, as well as in understanding major pollutant sources and production changes over time. A 15 m ice core representing 38 years of deposition (1977–2015) was collected from the Devon Ice Cap in Nunavut, providing us with the first multi-decadal temporal ice record in PFAA deposition to the Arctic. Ice core samples were concentrated using solid phase extraction and analyzed by liquid and ion chromatography methods. Both perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) were detected in the samples, with fluxes ranging from < LOD to 141 ng m−2 yr−1. Our results demonstrate that the PFCAs and perfluorooctane sulfonate (PFOS) have continuous and increasing deposition on the Devon Ice Cap, despite recent North American and international regulations and phase-outs. We propose that this is the result of on-going manufacture, use and emissions of these compounds, their precursors and other newly unidentified compounds in regions outside of North America. By modelling air mass transport densities, and comparing temporal trends in deposition with production changes of possible sources, we find that Eurasian sources, particularly from Continental Asia, are large contributors to the global pollutants impacting the Devon Ice Cap. Comparison of PFAAs to their precursors and correlations of PFCA pairs showed that deposition of PFAAs is dominated by atmospheric formation from volatile precursor sources. Major ion analysis confirmed that marine aerosol inputs are unimportant to the long-range transport mechanisms of these compounds. Assessments of deposition, homologue profiles, ion tracers, air mass transport models, and production and regulation trends allow us to characterize the PFAA depositional profile on the Devon Ice Cap and further understand the LRT mechanisms of these persistent pollutants.

Ice Core Record of Persistent Short‐Chain Fluorinated Alkyl Acids: Evidence of the Impact From Global Environmental Regulations

“…Fluorotelomer degradation leads to deposited PFCAs with ratios that are reasonably consistent with time. Pickard et al (2018) observed that all PFCAs with carbon chain lengths ≥5 have similar deposition trends through time to the same Devon Ice Cap ice core. Ratios among PFCAs with five to eight carbons are reproduced in Figure 2b and demonstrate the difference in deposition trends for PFBA.…”

“…(a) Comparison between GEOS‐Chem modeled (Thackray et al, 2020) and measured deposition ranges from 1978–2014 (Devon Ice Cap, black) and 1978–2015 (Mt. Oxford icefield, green); (b) measured molar ratios of PFCAs of different chain lengths from the Devon Ice Cap (C5 to C8 PFCA deposition from Pickard et al (2018)).…”

“…One outcome of these studies was that PFCAs can be formed through atmospheric oxidation of volatile fluorotelomer compounds (i.e., substances possessing F(CF 2 ) x CH 2 CH 2 R), which are used as synthetic precursors to commercial products (Ellis et al, 2004; Young & Mabury, 2010). Atmospheric degradation of fluorotelomer compounds has been shown to contribute to PFCA contamination in remote regions (Benskin et al, 2012; Pickard et al, 2018).…”

Per‐ and polyfluoroalkyl substances and their alternatives in paper food packaging

“…In 2001, the PFAS issue became very public when residents near DuPont‘s Washington, West Virginia manufacturing site filed a class action law suit due to the elevated PFOA levels in their drinking water (Frisbee et al., 2009; Head, 2019; Steenland et al., 2009). About the same time, the international community became alarmed to find that PFAS were not only commonly found in human serum but were also detected in wildlife, including wildlife found in the arctic and other remote areas (Del Vento et al., 2012; Giesy & Kannan, 2001; Hepburn et al., 2019; Lindstrom et al., 2011; MacManus‐Spencer et al., 2010; Perez et al., 2013; Pickard et al., 2018; Taves, 1968). The PFAS most commonly detected in the environment were long chain (C8) “legacy” chemicals, PFOA and PFOS.…”

“…The use of tainted recycled fiber or the use of tainted water for composting operations could account for the banned PFAS detected. It is also possible that some noncompliant food packaging entered the market via importation (Choi et al., 2019; Pickard et al., 2018).…”