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Dec 5, 2014 - ABSTRACT: This study investigated the role of a permanently manned Australian Antarctic research station (Casey Station) as a source of ...
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An Antarctic Research Station as a Source of Brominated and Perfluorinated Persistent Organic Pollutants to the Local Environment Seanan Wild,*,† David McLagan,‡ Martin Schlabach,§ Rossana Bossi,∥ Darryl Hawker,‡ Roger Cropp,‡ Catherine K. King,⊥ Jonathan S. Stark,⊥ Julie Mondon,# and Susan Bengtson Nash†

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Environmental Futures Research Institute, Griffith School of Environment, Griffith University, 170 Kessels Road, Nathan, QLD 4111, Australia ‡ Griffith School of Environment, Griffith University, 170 Kessels Road, Nathan, QLD 4111, Australia § The Norwegian Institute for Air Research (NILU), Kjeller NO-2027, Norway ∥ Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark ⊥ The Australian Antarctic Division (AAD), Kingston, Tasmania 7050, Australia # Deakin University, Princes Highway, Warrnambool, Victoria 3280, Australia S Supporting Information *

ABSTRACT: This study investigated the role of a permanently manned Australian Antarctic research station (Casey Station) as a source of contemporary persistent organic pollutants (POPs) to the local environment. Polybrominated diphenyl ethers (PBDEs) and polyand perfluoroalkylated substances (PFASs) were found in indoor dust and treated wastewater effluent of the station. PBDE (e.g., BDE-209 26−820 ng g−1 dry weight (dw)) and PFAS levels (e.g., PFOS 3.8− 2400 ng g−1 (dw)) in dust were consistent with those previously reported in homes and offices from Australia, reflecting consumer products and materials of the host nation. The levels of PBDEs and PFASs in wastewater (e.g., BDE-209 71−400 ng L−1) were in the upper range of concentrations reported for secondary treatment plants in other parts of the world. The chemical profiles of some PFAS samples were, however, different from domestic profiles. Dispersal of chemicals into the immediate marine and terrestrial environments was investigated by analysis of abiotic and biotic matrices. Analytes showed decreasing concentrations with increasing distance from the station. This study provides the first evidence of PFAS input to Polar regions via local research stations and demonstrates the introduction of POPs recently listed under the Stockholm Convention into the Antarctic environment through local human activities.



INTRODUCTION Persistent organic pollutants (POPs) are typically anthropogenic chemicals and ubiquitous global contaminants. They share properties of persistence, toxicity, bioaccumulation potential and propensity for long-range environmental transport (LRET).1−3 As such, POPs are recognized as posing a threat to environmental and human health and are subject to the Stockholm Convention on POPs that aims to reduce, and ultimately eliminate, these compounds from the environment. The first generation of POPs listed under the Convention were semivolatile chlorinated compounds undergoing LRET through atmospheric transport of vapor and particle-associated chemical fractions. These chemicals may therefore be redistributed to colder regions of the planet through global distillation and fractionation processes.4 Consequently, Polar regions of the Earth have accumulated a proportion of the world’s POP burden and hence have been a special focus for POP research.5 © 2014 American Chemical Society

Human activity in Polar regions, particularly the Antarctic, is undergoing rapid changes and is dramatically increasing.6,7 Easier access to both North and South Polar regions has resulted in enhanced research activity, as well as increasing tourism and marine resource exploration and extraction. Most Antarctic research bases are located in ice-free areas close to the coastline.8 These areas are also of great ecological significance. Because of this, and the fact that background POPs levels are generally relatively low, any consequent local contamination can have a disproportionately large effect on biota. Research bases have already been shown to be sources of PAHs and heavy metals along with Legacy POPs, such as PCBs.9−12 Received: Revised: Accepted: Published: 103

April 23, 2014 November 28, 2014 December 5, 2014 December 5, 2014 dx.doi.org/10.1021/es5048232 | Environ. Sci. Technol. 2015, 49, 103−112

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Figure 1. Map of Casey Station, Antarctica, and surrounds, depicting sampling sites used in this study.

extensively used as waterproofing or wetting agents, in many nonstick or polytetrafluoroethylene (Teflon) containing products as well as in fire-fighting foam.15 They may also be formed in situ from degradation of volatile precursors such as fluorotelomer alcohols (FTOHs).16 FTOHs are used extensively as intermediates in the manufacture of poly- and perfluoroalkylated substances (PFASs), have been identified as residual compounds in consumer products such as stain repellents and other surfactants, and are known to have their own detrimental environmental and health effects.17,18 PBDEs on the other hand are hydrophobic and commonly found in fire retardant mixtures as well as building materials, electronics and textiles.19 The potential for PBDEs to be released from remote polar research stations, due to the relatively high density of electronic equipment and increased fire prevention concerns at these locations, has been recognized.20 PBDEs21−24 and PFASs such as PFOS25,26 may be released from consumer products as these products wear and degrade. Their contrasting physicochemical properties will influence subsequent distribution. As they are persistent they can accumulate in organisms with detrimental effects, including hepato-, immune-, and ontogenetic toxicity.25−27 Evidence of polar research introducing contemporary POPs to the local environment was first presented in 2008 by Hale et al.20 and Bengtson Nash et al.28 The former investigated both the McMurdo and Scott Stations in the Ross Sea region of Antarctica. They found high levels of PBDE in indoor dust and wastewater sludge from McMurdo Station, reflecting its size and scale of activities. In this study we investigated levels of PBDEs and, for the first time, PFASs in the indoor dust and treated wastewater effluent of a permanently manned Antarctic research base. We also investigate a suite of abiotic and biotic matrices, sourced at increasing distance from the station to determine the role of the

Assessing and monitoring local source contributions of recently used contemporary POPs on the Antarctic continent will be of growing importance as human activity in the region further expands. Similarly, chemical monitoring represents a fundamental requirement under the Protocol on Environmental Protection to the Antarctic Treaty (the Madrid Protocol) adopted in 1991. This protocol has been established to limit the long-term impacts of direct human activity on the Antarctic environment through monitoring the effectiveness of conservation measures and remedial strategies around Antarctic bases.13,14 The protocol explicitly prohibits the importation of specific POPs of known risks. The combination of the Stockholm and Madrid protocols, as well as the significance of Antarctica as the world’s largest scientific preserve, underlines the importance of monitoring pollutants as an essential component of ongoing Antarctic research programs. Alongside the increasing scale of human activity in Polar regions, the list of industrial and consumer chemicals that satisfy the classification criteria of a POP continues to grow. These factors result in an increased potential for POPs to be directly introduced to the local environment as fresh emissions from consumer products, including electronic equipment, textiles and furnishings, many of which contain POPs recently annexed under the Stockholm Convention. For example perfluorooctanesulfonic acid and its salts together with perfluorooctane sulfonyl fluoride have been added to Annex B (Restriction) and the penta- and octa-commercial mixtures of polybrominated diphenyl ethers (PBDEs) to Annex A (Elimination). These fluorinated and brominated compounds have different physicochemical properties and hence different industrial and commercial uses. Perfluoroalkyl acids for example are generally manufactured as their salts15 such as perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) that are amphiphilic with low volatility. Such compounds have been 104

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(4 fluorotelomer alcohols (FTOHs), 2 perfluoroalkyl sulfonamides (FOSAs) and 2 perfluoroalkyl sulfonamidoethanols (FOSEs)) were targeted; perfluorobutyl ethanol (4:2 FTOH), perfluorohexyl ethanol (6:2 FTOH), perfluorooctyl ethanol (8:2 FTOH) and perfluorodecyl ethanol (10:2 FTOH) as well as N-Ethyl-heptadecafluorooctane sulfonamide (N-Et-FOSA), N-Methyl-heptadecafluorooctane sulfonamide (N-Met-FOSA), N-Ethyl-heptadecafluorooctane sulfonamidoethanol (N-EtFOSE) and N-Methyl-heptadecafluorooctane sulfonamidoethanol (N-Met-FOSE). Native and labeled compounds (13C and deuterium-labeled) were bought as a mixture from Wellington Laboratories (Guelph, ON, Canada). Extraction and Quantification. Extraction and cleanup of samples for all PBDE analyses were undertaken at the Norwegian Institute for Air Research (NILU), Kjeller, Norway. Samples were sent frozen at −20 °C. Reagents used at NILU were hexane, dichloromethane, ethyl acetate, cyclohexane and toluene (GC grade), concentrated hydrochloric acid, isooctane (analytical grade), sodium sulfate (anhydrous for analysis) and silica gel (0.063−0.200 mm, for column chromatography) purchased from Merck (Germany). Diethyl ether (glass distilled grade) was purchased from Rathburn (Scotland). Sample extraction and cleanup was performed using the methods described in Mariussen et al.35 by either Soxhlet extraction (soil, dust, phytoplankton, moss, lichen and treated wastewater particulates) or by cold column extraction (fish, amphipods). This was followed, for all samples, by concentration and solvent exchange with hexane prior to clean up by concentrated hydrochloric acid (HCl), and activated silica. Quantification was performed by gas chromatography/electron ionization-high resolution mass spectrometry (GC/EI-HRMS). Quantification of the PBDE congeners present in the purified extracts was carried out using 13C-labeled BDE-28, -47, -99, -153, -183, and -209 as internal standards (50 μL of a 270 pg μL−1 mixed congener standard and 50 μL of a 2520 pg μL−1 BDE-209 standard). Mean recoveries for 13C labeled internal standards are shown in SI Table S2. For ∑PBDEs these ranged between 62 (±13) and 169 (±69)% for the various sample types. Indoor dust, wastewater, amphipod, moss and lichen samples were extracted and analyzed for PFAS at Aarhus University, Denmark. Ammonium acetate (98%), sodium carbonate (99.5%), sodium hydrogen carbonate (99.7%), methanol (>99.9%), and methyl tert-butyl ether (MTBE, 99.5%) for this were purchased from Merck (Darmstadt, Germany). The extraction method used for determination of the ionic PFAS in amphipods, moss and lichens was based on ion pairing as described by Hansen36 with some small modifications as noted in Bossi et al.37,38 Dust samples were extracted twice with 5 mL methanol and the extract cleaned up on EnviCarb solid phase columns (100 mg, 3 cm3, Supelco). The extraction of wastewater samples was based on the method described by Bossi et al.38,39 Instrumental analysis of perfluorinated carboxylates and sulfonates was performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI) as described by Bossi et al.38 Quantification of these analytes was carried out using response factors calculated from a four-point calibration curve consisting of blank samples (bovine liver) spiked with the analytes in the concentration range 25−500 ng g−1 wet weight and extracted following the same procedure as for samples.

station in introducing contemporary POPs into the local Antarctic environment.



EXPERIMENTAL SECTION Sampling Locations. Casey Station (Figure 1) (66°16′56″S 110°31′32″E) is situated on an ice-free coastal peninsula in Wilkes Land, Eastern Antarctica. Soil development is poor, being composed largely of rock and gravel. Mosses and lichens exist in the immediate station vicinity and the nearby littoral marine environment supports a diverse community of algae, invertebrates and fish.29 Casey Station has five main buildings viz. the main living quarters (consisting of an old wing, opened in 1988, and a new wing opened in summer 2011/12), a workshop, a warehouse, a science building, and a communications building. The station has a secondary wastewater treatment plant utilizing a rotating biological contactor, with a design flow capacity of 5000 L per day.30 However, at times of peak occupancy, the efficiency of this wastewater treatment process can be decreased greatly due to input volumes exceeding the system’s design capacity. The system may also be put on bypass for periods of 1−2 weeks during the summer for maintenance shutdown. BOD levels in the effluent can vary from 10 mg L−1 over winter to 100−200 mg L−1 in the high occupation summer months (November to March). Similarly, the average suspended solids concentrations in effluent during November to March is 24 mg L−1, but can vary from almost zero up to more than 120 mg L−1 outside of these months.30 Increased levels of suspended solids in the effluent can result in elevated levels of particularly hydrophobic contaminant fractions being discharged. Food wastes are not included in waste treatment influent and along with wastewater sludge, are repatriated from Antarctica to Australia.31,32 The location of marine sampling locations and their distance from Casey Station wastewater outfall is described in Supporting Information (SI) Table S1. Two additional potential contamination sources of note in the local area are the Thala Valley dump-site and Casey Wharf. The former was used as rubbish tip for disposal of waste until the mid-1980s,33,34 while the wharf is the site for cargo loading/ unloading, refuelling and launching of small vessels. Sample Collection. Samples from nine different abiotic and biotic matrices in the local terrestrial environment (indoor dust (n = 16), soil (n = 4 composite samples), lichen (n = 5), and moss (n = 5)) and marine environment (treated wastewater (n = 9), sediment (n = 3), phytoplankton (n = 3), amphipods (n = 6), and fish tissue (n = 6)) were collected over one or more of the 2008/09, 2009/10, 2010/11, 2011/12, and 2012/13 summer expedition periods. Sample collection details are found in SI Text S1. Chemical Analysis. Analytes. Samples were analyzed for 17 PBDE congeners: BDE-28, -47, -49, -66, -71, -77, -85, -99, -100, -119, -138, -153, -154, -183, -196, -206, and -209. Samples were also separately analyzed for perfluorooctanesulfonamide (PFOSA) together with 15 perfluorinated carboxylates and sulfonates; perfluorobutanesulfonate (PFBS), perfluorohexanesulfonate (PFHxS), perfluoroheptanesulfonate (PFHpS), perfluorooctanesulfonate (PFOS), perfuorodecanesulfonate (PFDS), perfluoropentanoate (PFPeA), perfluorohexanoate (PFHxA), perfluoroheptanoate (PFHpA), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUnA), perfluorododecanoate (PFDoA), perfluorotridecanoate (PFTrA) and perfluorotetradecanoate (PFTeA). For dust samples, a further 8 PFASs 105

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Table 1. Major PBDE Congener Concentrations (ng g−1 Dry Weight) (and % Contributions to ∑PBDE) in Indoor Dust Collected at Casey Station in 2011 Compared to Values From McMurdo and Scott Stations Antarctica. 20 compound

warehouse (n = 1)

living quarters (n = 1)

communications building (n = 1)

science building (n = 1)

McMurdo Station

Scott Station

BDE-47 BDE-99 BDE-183 BDE-209 ∑PBDEs

ND 4.1 (9.8%) ND 26.3 (63.4%) 41.5

7.7 (3.5%) 10.8 (5.0%) 9.5 (4.4%) 180.1 (83.3%) 216.2

22.4 (7.1%) 20.6 (6.5%) 5.0 (1.6%) 246.0 (78.0%) 281.8

24.9 (2.6%) 49.7 (5.3%) 13.7 (1.46%) 822.2 (87.3%) 903.3

1100 (11.5%) 1330 (13.9%) 369 (3.9%) 4160 (43.5%) 9560

111 (5.0%) 156 (7.0)% 15.1 (0.7%) 1650 (73.7%) 2240

Figure 2. Plots of PBDE congener concentration (ng g−1) with distance from Casey Station for various biotic matrices. Trend lines shown are indicative of decreasing PBDE concentrations with increasing distance from station. Note: trend lines are indications of the decrease in concentration but are based on limited sample size and do not imply statistical significance. A. Lichen Samples. B. Moss Samples. C. Amphipod Samples. D. Fish Muscle and Liver Samples.

detection for PFAS analyses are summarized in SI Tables S4 and S5.

For the analysis of FTOHs and FOSAs/FOSEs in dust samples, 0.5 g of dust was spiked with isotope labeled compounds then extracted twice with 5 mL ethyl acetate and the extract analyzed by GC-MS with positive chemical ionization (PCI). QA/QC. In addition to the use of internal and recovery standards a number of other quality-control procedures were used. Field blanks were also incorporated for dust sampling and analyzed to characterize sample contamination through vacuum collection (laboratory and field blank values for PBDE and PFAS analysis are found in SI Tables S3−S5). Biological samples were, where possible, pooled from multiple individuals. Where field blanks were unavailable, laboratory blanks were deducted from sample concentration. NILU regularly participates in international laboratory intercalibrations, including those for PBDE analyses.40 The samples for PFAS were extracted and analyzed in batches together with a procedural blank. The detection limit of the analytical method (MDL) was defined as those concentrations of the analytes needed to produce a signal-tonoise ratio (S/N) of 3:1. Field blank values and limits of



RESULTS AND DISCUSSION PBDEs in Terrestrial Samples. Indoor Dust. PBDEs were detected in indoor dust samples of all four station buildings sampled (Table 1). By mass, BDE-209 was the most abundant congener, followed by BDE-99 and BDE-47, both at considerably lower levels.20 Minor contributions from BDE183, -153 and -100 were also observed in some samples. The PBDE congener profile in samples from the current study closely resembles those published for indoor dust from homes and offices in southeast Queensland, Australia, living quarters at Scott and McMurdo Stations in Antarctica and homes in Birmingham UK.20,41,42 Hale et al.20 suggest PBDE congener profiles in indoor dust at polar research stations mirror usage within their host nations and our findings here support this observation. As with PBDE profiles for McMurdo Station and Scott Station, results indicate inputs predominantly from the deca-commerical mixture and to a lesser extent also the penta-commercial mixture, with very little contribution 106

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concentration of this congener (0.60 ng g−1 (dw)). BDE-206 was the only other congener detected at more than one site, with concentrations of 0.108 ng g−1 (dw) and 0.56 ng g−1 (dw) at sites 1 and 2 respectively. PBDE results for moss samples (Figure 2B) showed a similar profile to those found for lichen, although levels were 1−2 orders of magnitude greater in the moss than in lichen. Similar findings by Yogui and Sericano44 and Cipro et al.45 were attributed by the authors to differing uptake mechanisms for PBDEs. Bryophyte research in the Casey station region has however recently revealed unusually high 15N stable isotope ratios of mosses, indicating that moss beds in the region are supported by fossilized seabird guano.46 Higher organic carbon content of moss, combined with the vastly different sampled lichen and moss morphologies (foliose lichen compared to dense, high surface area to volume ratio moss mats) are likely key factors contributing to the differences observed in this study. Work carried out by Mariussen et al.47 in the Arctic attributed the presence of the relatively nonvolatile BDE-209 in their moss samples to atmospheric transport of this congener sorbed to particles. In the context of this current work, the distance separating the Antarctic continent from hemispheric sources suggests a local anthropogenic source is likely, although some contribution from LRET cannot be discounted.44 The detection of PBDEs in lichens and mosses in close proximity to the station, combined with the knowledge that they are major biotic components of terrestrial Antarctic ecosystems13 and regarded as good indicators of atmospheric deposition of POPs, underlines their suitability as biomonitoring tools to further investigate the extent of local source contributions of contemporary and traditional POPs.48 PBDEs in Marine Samples. Treated Wastewater Effluent. Wastewater effluent is a means by which PBDEs can be spread to the local marine environment. The PBDE profiles of the treated wastewater samples were similar to indoor dust as they were dominated by BDE-209 (maximum of 400 ng L−1), with concentrations expressed on a volume of whole effluent basis (SI Table S8). Congeners BDE-99 and -47 were detected at the second highest levels albeit with much lower mean concentrations (90%: 530 ng g−1 OC), with lower amounts of BDE-47 (0.8%), BDE99 (0.5%) and BDE-206 (3.2%). The dominance of, and absolute concentration of, BDE-209 are very similar to those

from the octa-mixture (Table 1). The deca-commercial mixture was the most widely used brominated flame retardant in the world until it was banned in electrical and electronic equipment by the EU (2008), and production in the U.S. discontinued (2013).43 The highest concentrations in this study were found in the communications and science buildings. These buildings contain a higher density of electronic equipment, a known source of PBDEs, especially the deca-commercial mixture. The lowest levels of PBDEs were found in dust from the warehouse, a comparatively well-ventilated facility with little electronic equipment. PBDE levels in dust of bedrooms and hallways in the new wing of the living quarters were determined in 2012/13 and compared to levels in the old wing that has been occupied since construction in 1988 (SI Table S6). The old wing had the highest levels of PBDEs but all samples had the same profile with BDE-209 the most abundant congener followed by BDE99 and BDE-47, both at considerably lower levels. In comparison to the U.S. operated McMurdo Station, PBDE concentrations found in indoor dust from living quarters in both Casey’s old and new wings were much lower. For example, levels of BDE-209 at McMurdo were one and a half times those in the bedrooms of the old wing at Casey Station and four times those in the new wing. McMurdo is a much larger facility (summer occupancy up to 1200 personnel) than Casey Station (summer occupancy up to 90 personnel). New Zealand’s Scott Station (summer occupancy up to 86 personnel) is similar in size to Casey Station and the concentrations of the BDE-209 in indoor dust from living quarters measured in 2006 were intermediate between those in the bedrooms of new and old wings at Casey Station.20 Soil. To investigate dispersal to the immediate terrestrial environment, four soil samples were collected at distances up to 800 m from the base. PBDEs were only detected in the two samples obtained near the wharf and main fuel tanks (SI Table S7). These samples were dominated by BDE-209, with the congener making up almost 90% of the ΣPBDEs (1590 ng g−1 organic carbon (OC) or 8.5 ng g−1 (dw) for the fuel tank sample and 100% of the ∑PBDEs in the wharf sample (205 ng g−1 OC or 0.43 ng g−1 (dw)). Antarctic soils are generally undeveloped and characterized by low moisture and organic carbon contents as well as large grain size.13 In the Casey station region, this characteristic is exacerbated by the practice of rock quarrying for road surfaces. As a result, most of the soil in the area now contains a large amount of this rocky material. The organic carbon content of all soil samples (90% of PBDEs detected at all sites. The concentration of BDE-209 at the two sites closest to the station, sites 1 (2.3 ng g−1 (dw)) and site 2 (2.5 ng g−1 (dw)) were approximately four times higher than site 4, which had the next highest 107

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47. There was, however, considerable variation in the concentrations of specific congeners between samples. In a review of PBDEs in the Arctic, de Wit et al.51 determined that for all studies addressing PBDEs in marine fish, BDE-47 was the main congener present. Within the vicinity of the Antarctic Peninsula, BDE-47 has been reported as the dominant PBDE congener in a variety of marine organisms including T. bernacchii, Antarctic krill (Euphausia superbia) and in three penguin species (Pygoscelis adeliae, Pygoscelis antarctica and Pygoscelis papua).55,56 Although BDE-209 accumulates in fish tissue, it is metabolized and transformed (debrominated) in the fish liver resulting in the accumulation of a variety of reductive products ranging from penta- to octa-BDEs.19,57 T. bernacchii samples analyzed for PBDEs by Hale et al.20 at varying distances from McMurdo Station also showed a dominance of BDE-47. These results were, however, not based on organisms pooled according to sampling distance from the station and unlike those of the present study did not show a consistent decreasing gradient with distance from the treated wastewater outfall. However, we agree with these authors’ caution against routine application of such larger, more mobile species as bioindicators of local source contributions PFASs in Terrestrial Samples. Indoor Dust. All 15 of the perfluorinated carboxylates and sulfonates analyzed in the indoor dust collected at Casey Station were present at detectable levels (SI Table S12). To the authors’ knowledge this represents the first detection of PFAS contamination within an Antarctic research station. PFOS was generally detected at the highest levels, often more than 10 times higher than any other compound, with the highest concentrations of 2370 ng g−1 (dw) and 1010 ng g−1 (dw) detected within the warehouse in 2011 and 2012 respectively. PFOA was also detected at concentrations of up to 80 ng g−1 (dw), dominating in two samples collected from the station’s living quarters in the most recent (2013) sampling campaign. The levels of these PFASs reported in the current study are comparable to levels reported for houses and offices around the world.58,59 However, some Casey Station samples, particularly those from the warehouse, were distinctive in the proportion of PFOS compared to PFOA (SI Table S13) with the level of PFOS in some instances two or 3 orders of magnitude greater than PFOA. In contrast, many other studies report the ratio in domestic indoor dust samples to be less than 1 order of magnitude, for example, samples from homes in the UK reported 450 ng g−1 PFOS and 340 ng g−1 PFOA.59 For the FTOHs, only the 4:2 compound, perfluorobutyl ethanol, was not detected. Levels of the remaining analytes were highest in living areas, ranging up to 900 ng g−1 (dw) for 8:2 FTOH (perfluorooctyl ethanol), with comparatively low levels in workshop and warehouse areas (SI Table S14). Given the relative volatility of FTOHs, these dust concentrations suggest that vapor phase levels in parts of the base could be significant. FTOHs (70% contribution of PFAS in both the particulate and dissolved phases) in the samples collected in 2011 was reduced in the 2012 samples where it made up only about 30% of the PFAS burden of these phases. PFDS, a compound that has been commonly found in U.S. domestic wastewater sludge and contaminated or industrial areas,67 made up about 22% of the 2011 PFAS particulate phase, while PFOA contributed only about 5% to the PFAS burden of the dissolved phase. Overall, the concentration of PFASs detected in the dissolved phase was two to six times higher than in the particulate phase, reflecting the greater hydrophilicity of ionic perfluorinated compounds compared to traditional POPs. Various studies have shown wastewater treatment plants to be sources of perfluorinated compounds to the environment. Polar research activities routinely utilize PFAS-containing waterproofing products, such as the Gore-Tex outerwear worn by resident personnel. It has been reported that over two years of regular washing such clothing loses approximately 73% of the PFAS treatment.68 Excluding the dissolved phase data for 2011, the levels of PFASs found in wastewater from Casey Station are similar to, though on the higher end of, the range typically seen in primary and secondary treated wastewater from Australia69 and other developed countries such as Germany70 and Denmark.38 The results for PFOS in the 2011 samples (184 ng L−1), however, is much higher than those typically seen in residential or mixed industrial and commercial waste (between 10 and 40 ng L−1)69,70 and more representative of industrial wastewater levels.38,70 It is possible that this elevated burden resulted from temporary plant inefficiencies due to increased occupancy during the Antarctic summer, but nonetheless represents a net discharge of chemicals directly to the receiving environment. Amphipods. Although the benthic habitat of amphipods is one where particulate material from the treated wastewater effluent may settle, there is currently no evidence of uptake or adsorption at levels above the method level of detection of PFASs (0.02 to 0.10 ng g−1 (dw)) (SI Table S4). PFAS dispersal to the terrestrial and marine environments from Casey station via pathways such as treated wastewater effluent and dust thus appears more limited at present than that of PBDEs. This perhaps reflects factors such as usage patterns and the different physicochemical characteristics of members of these groups. The continent is the focus of increased scientific activity, much of which is carried out from bases such as Casey

Figure 3. Comparison of PFOS, PFOA and PFDA (A.) and FTOH (B.) levels in indoor dust samples between old and new wings of Casey Station living quarters in ng g−1 dry weight. Samples for these analyses were collected in the 2011 and 2012 sampling campaigns.

may reflect reduced commercial production of PFOS since its peak in 1999/2000 together with restriction on usage following listing in Annex B of the Stockholm Convention in 2009.26,65 Also in comparison, dust from areas of the old wing were shown to have much higher levels of 6:2 FTOH, whereas the new wing had slightly higher levels of 8:2 FTOH. Levels of 10:2 FTOH were comparable between these locations (Figure 3B). Lichen and Moss. PFOS was the only PFAS detectable (≤1.7 ng g−1 (dw)) in these sample matrices and was only quantified in the two moss samples from closest to the station (0 and 100 m). This possibly reflects both a lower affinity for organic matter compared to PBDEs because of its ionic nature and a rapid decrease of dust-associated PFAS levels with distance away from the point source of pollution. PFASs in Marine Samples. Treated Wastewater Effluent. Recent examination of PFAS partitioning in wastewater effluent showed a presence in both dissolved and particulate phases,66 109

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station occupying coastal, ice-free zones of great ecological importance and sensitivity. However, unlike the Arctic, Antarctica is subject to the Madrid Protocol system of environmental protection, applicable to all human activities including those at research stations. As human activities in Polar regions continue to expand and the diversity of chemical applications grow, it is necessary to establish the extent and impact of chemical contamination on the local environment, now and in the future.



ASSOCIATED CONTENT

S Supporting Information *

Information on sampling methods used in this study and expanded results for each sampled matrix along with blank values and limits of detections for analyses are provided in the Supporting Information. This material is available free of charge via the Internet at http://pubs.acs.org.



AUTHOR INFORMATION

Corresponding Author

*Phone +61 0437827946; e-mail: s.wild@griffith.edu.au. Notes

The authors declare no competing financial interest.



ACKNOWLEDGMENTS This work was partially funded by an Australian Antarctic Science Grant (3115). The authors thank Michael Packer, Emily Shaw and Chris Shaw for assistance in sample collection and Inga Jensen for assistance in analysis. David Smith and the Australian Antarctic Division Data Centre are acknowledged for provision of local area maps. We also thank the anonymous reviewers for their contribution to the publication of this work.



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