Arctic Contamination Research Articles

Assessment of persistent organic pollutants in killer whales (Orcinus orca) of the Canadian Arctic: Implications for subsistence consumption and conservation strategies

Killer whales (Orcinus orca) historically restricted to certain Arctic regions due to extensive sea ice have recently been documented farther north and for longer durations in the Canadian Arctic. These apex predators accumulate high levels of persistent organic pollutants (POPs). The objective of this study was to evaluate the concentrations and profiles of POPs in killer whales of the Canadian Arctic, thus determining potential risks for Inuit communities if consumed. Biopsies were collected from 33 killer whales across areas of the Canadian Arctic between 2009 and 2021. Significant variability in POP concentrations was observed among whales. The cumulative POP concentrations ranged from 12 to >2270 mg/kg lw, representing ∼200-fold increase from the least to the most contaminated individual. The rank order of concentrations of the top five contaminant classes was ∑DDT, ∑PCB, ∑CHL, ∑Toxaphene, and Dieldrin. Several emerging Arctic contaminants were detected, including chlorpyrifos, endosulfan, pentachloroanisole, and polychlorinated naphthalenes, although at relatively lower concentrations than legacy POPs. Considering the elevated blubber POP levels in killer whales, recommended daily consumption thresholds, established based on human tolerable daily intake (TDI) values, were notably restricted for ∑PCB (<0.14 g), ∑DDT (<6.9 g), ∑CHL (<13 g), dieldrin (<8 g) and heptachlor epoxide (<5 g). Killer whales in the Canadian Arctic exhibited higher POP concentrations than other commonly hunted species such as polar bears, ringed seals, and Arctic char. We acknowledge that a more holistic risk assessment of diet is required to assess the cumulative impacts of contaminant mixtures as well as nutritional quality of tissues commonly consumed by northern communities.

Soil contamination by diesel fuel destabilizes the soil microbial pools: Insights from permafrost soil incubations

Arctic contamination by diesel fuel (DF) is of great concern because of the uncertain feedback of permafrost carbon (C) and soil microbiota to DF in the context of climate change in high latitudes. We conducted a laboratory incubation experiment with a gradient of DF addition ratios to examine the responses of the soil microbiota of the typical permafrost soils in the tundra ecosystems of the Norilsk region (Siberia). The study revealed initial heterogeneity in the microbial activity of the studied soils (Histic Gleyic Cryosols (CR-hi,gl), Turbic Cryosols (CR-tu), Turbic Spodic Folic Cryosols (CR-tu,sd,fo), Gleyic Fluvisols (FL-gl)). We applied the two-pool model for evaluation of the effect of DF on the proportions of C pools and revealed significant differences between soil types in the fast and slow C pools in response to DF addition. The results showed that DF addition treatments had varying effects on the fast and slow C pools, microbial activity, and microbial community structure in the studied soils. For minor exceptions, DF dramatically accelerated C loss from the slow C pool in all soil types. We assume that differences in C pool and microbiota responses to DF addition were caused by soil texture and changes in microbial community structure. We isolated Serratia proteamaculans, S. liquefaciens, S. plymuthica, Rhodococcus erythropolis, Pseudomonas antarctica, P. libanensis, P. brassicacearum, and P. chlororaphis from the DF-polluted soils. These species are recommended for bioremediation to mitigate the DF contamination of permafrost soils, especially regarding climate change and the sustainable well-being of Arctic ecosystems.

Forty-Year Biomonitoring of Environmental Contaminants in Russian Arctic: Progress, Gaps and Perspectives.

This article presents a comprehensive survey of the studies on the biomonitoring of persistent organic pollutants (POPs) and metals in biota and human tissues on the territory of the Russian Arctic. It is concluded that a relatively small number of studies were carried out during the last 40 years; for several Russian Arctic regions there is no data up to date, and for some regions the data are scarce, with most of the studies carried out in 1990s, followed by the large-scale GEF/AMAP/RAIPON project of 2001–2004 covering four regions. After that, single projects have been implemented in a few regions. Only the Nenets okrug and the Chukotka okrug (and hardly the Murmansk oblast) can be attributed as the regions where the biomonitoring of contaminants was carried out during last decades on several occasions, and for which the content of POPs and metals in biota and the human organism was assessed in 12–15-year dynamic trends (at least “at three points”). For the rest of the Russian Arctic territories, only fragmentary “cross-sections” of biomonitoring data is available, mainly obtained in the 1990s or early 2000s, which do not allow judging either the dynamics of the processes or the current state of affairs. The overwhelming majority of the studies in the Russian Arctic (more than 90%) were carried out within the framework of international projects, i.e., with cofinancing, assistance and contribution (including laboratory analyses) from the foreign colleagues and partners. The shortcomings of the Russian system of biomonitoring, including the weakness of the laboratory and research base, are considered. Perspectives of the Russian Arctic biomonitoring are discussed in detail, with the proposal of the elaboration of the national Russian Arctic Contaminants Program (RACP).

Suspect Screening of Liquid Crystal Monomers (LCMs) in Sediment Using an Established Database Covering 1173 LCMs.

Recent studies have suggested that liquid crystal monomers (LCMs) are emerging contaminants in the environment, and knowledge of this class of substances is very rare. Here, we reviewed existing LCM-related documents, i.e., publications and patents, and established a database involving 1173 LCMs. These 1173 LCMs were further calculated for their physicochemical properties, i.e., persistence (P), bioaccumulation (B), long-range transport potential (LRTP), and Arctic contamination and bioaccumulation potential (ACBAP). We found that 476 out of them were P&B chemicals (99% of them were halogenated), and 320 of them could have ACBAP properties (67% of them were halogenated). This LCM database was further applied for suspect screening of LCMs in n = 33 sediment samples by use of gas chromatography coupled to quadrupole time-of-flight mass spectrometry (GC-QTOF/MS). We tentatively identified 26 LCM formulas, which could have 43 chemical structures. Two out of these 43 suspect LCM candidates, 1-butoxy-2,3-difluoro-4-(4-propylcyclohexyl) benzene (3cH4OdFP) and 1-ethoxy-2,3-difluoro-4-(4-pentyl cyclohexyl) benzene (5cH2OdFP), were fully confirmed by a comparison of unique GC and MS characteristics with their authentic standards. Overall, our present study expanded the previous LCM database from 362 to 1173, and 1173 LCMs in this database were calculated for their physicochemical properties. Meanwhile, taking n = 33 sediment samples as an exercise, we successfully developed a suspect screening strategy tailored for LCMs, and this strategy could have promising potential to be extended to other environmental matrices.

Climate change influence on the levels and trends of persistent organic pollutants (POPs) and chemicals of emerging Arctic concern (CEACs) in the Arctic physical environment - a review.

Climate change brings about significant changes in the physical environment in the Arctic. Increasing temperatures, sea ice retreat, slumping permafrost, changing sea ice regimes, glacial loss and changes in precipitation patterns can all affect how contaminants distribute within the Arctic environment and subsequently impact the Arctic ecosystems. In this review, we summarized observed evidence of the influence of climate change on contaminant circulation and transport among various Arctic environment media, including air, ice, snow, permafrost, fresh water and the marine environment. We have also drawn on parallel examples observed in Antarctica and the Tibetan Plateau, to broaden the discussion on how climate change may influence contaminant fate in similar cold-climate ecosystems. Significant knowledge gaps on indirect effects of climate change on contaminants in the Arctic environment, including those of extreme weather events, increase in forests fires, and enhanced human activities leading to new local contaminant emissions, have been identified. Enhanced mobilization of contaminants to marine and freshwater ecosystems has been observed as a result of climate change, but better linkages need to be made between these observed effects with subsequent exposure and accumulation of contaminants in biota. Emerging issues include those of Arctic contamination by microplastics and higher molecular weight halogenated natural products (hHNPs) and the implications of such contamination in a changing Arctic environment is explored.

An Overview of National and International Environmental Laws pertaining to Arctic States and Their Work with the Arctic Council

The latest International Panel on Climate Change (IPCC) report published in August 2021 demonstrated that the Arctic region drastically feels the impacts of climate change. Several laws and policies contribute to the governance of the reduction of emissions which impact the Arctic polar region. This work will analyse the inclusion of language relating to the Arctic region in several key Arctic countries’ climate policies and in their Nationally Determined Contributions (NDCs) submitted in requirement of being parties to the Paris Agreement. Arctic policies of these same countries will then be analysed to determine the degree to which they stipulate action relating to the Arctic environment. Finally, the several research projects and initiatives conducted by the Arctic Council’s two working groups, the Arctic Monitoring and Assessment Programme (AMAP) and the Arctic Contaminants Action Programme (ACAP), will be overviewed to demonstrate their contributions to the best available science and practice in the region. This paper will look into how, and to what extent, the research of the Arctic Council working groups can be considered a mechanism of soft law in Arctic environmental governance. Consideration will also be given to how this relates to soft law governance stemming from the Law of the Sea (LOSC).

Long-Chain Chlorinated Paraffins Have Reached the Arctic

Chlorinated paraffins (CPs) were analyzed in marine wildlife from Greenland, Iceland, and the Swedish west coast. CPs up to C29 were detected in the samples from the Arctic, indicating long-range transport of an industrial chemical group with a 2-million-ton annual production volume. CP concentrations were generally higher in biota from the Swedish west coast. The Sweden/Arctic concentration ratios for very-short-chain (vSCCPs, C<10), short-chain (SCCPs, C10–13), medium-chain (MCCPs, C14–17), and long-chain CPs (LCCPs, C>17) in cetacean and bivalve species were in the range of 3.6–150, 5–29, 3–11, and 11–450, respectively. For the first time, fetal accumulation of four CP classes was found, whereby concentrations were 3.4 to 4.5 times lower in the fetus relative to the pregnant female minke whale. Cetacean blubber contained a higher proportion of higher chlorinated CPs compared to muscle tissue, while muscle contained higher lipid-normalized concentrations of longer chain CPs than blubber tissue. LCCPs predominated (52% of total CPs) in the muscle of a killer whale from Swedish waters, which is the first report where concentrations of LCCPs surpassed those of other CPs in marine mammals. This study shows that, like other CP classes, LCCPs are Arctic contaminants that may adversely affect biota in this remote region.

Improving the work of the Arctic Council: challenges and recommendations

Abstract The Arctic Contaminants Action Programme (ACAP), originally intended to follow up the work of AMAP (the Arctic Monitoring and Assessment Programme) on identifying the sources of pollution, became an official working group under the Arctic Council in 2006. ACAP has focussed on pollution from Russian sources, the main objective being to accelerate the reduction of national emissions of various environmental pollutants and climate forcers. Basically, ACAP initiates projects with a scientific basis in AMAP assessments of the health of the Arctic. The idea behind the creation of ACAP was to channel the work of the Arctic Council in a more practical direction and to improve the use of the knowledge produced by AMAP. ACAP is one of only two Council working groups not to have been specifically evaluated and analysed by external bodies and academics. This article undertakes a critical analysis of ACAP and argues that there are great potentials for improving its work. ACAP has established a forum where it has been possible to facilitate pilot projects aimed at limiting harmful emissions; this work should be strengthened.

Russia in the Arctic Chair: Adapting the Arctic Governance System to Conditions Prevailing in the 2020s

Abstract At the Arctic Council’s Ministerial Meeting in Reykjavik on 20 May 2021, Russia assumed the chairmanship of the council for the second time since its establishment in 1996. Though some Russian analysts and practitioners were skeptical about the usefulness of such a mechanism during the 1980s and 1990s, Russia has become an active contributor to the progress of the Arctic Council (AC). Russia’s first term as chair during 2004–2006 led to the creation of the Arctic Contaminants Action Program as an Arctic Council Working Group. Since then, Russia has served as co-lead of the Task Forces developing the terms of the 2011 agreement on search and rescue, the 2013 agreement on marine oil spill preparedness and response, and the 2017 agreement on enhancing international scientific cooperation. Russia also has participated actively in the creation of related bodies including the Arctic Coast Guard Forum and the Arctic Economic Council whose chairmanships rotate together with the chairmanship of the AC. Now, far-reaching changes in the broader setting are posing growing challenges to the effectiveness of these institutional arrangements. The impacts of climate change in the high latitudes have increased dramatically; the pace of the extraction and shipment of Arctic natural resources has accelerated sharply; great-power politics have returned to the Arctic foregrounding concerns regarding military security. Together, these developments make it clear that a policy of business as usual will not suffice to ensure that the AC remains an important high-level forum for addressing Arctic issues in a global context. The programme Russia has developed for its 2021–2023 chairmanship of the council is ambitious; it proposes a sizeable suite of constructive activities. In this article, however, we go a step further to explore opportunities to adapt the Arctic governance system to the conditions prevailing in the 2020s. We focus on options relating to (i) the AC’s constitutive arrangements, (ii) links between the council and related governance mechanisms, (iii) the role of science diplomacy, and (iv) the treatment of issues involving military security. We conclude with a discussion of the prospect of organising a heads of state/government meeting during the Russian chairmanship as a means of setting the Arctic governance system on a constructive path for the 2020s.

Organophosphate Esters in the Canadian Arctic Ocean

Eleven organophosphate esters (OPEs) were detected in surface water and sediment samples from yearly sampling (2013-2018) in the Canadian Arctic. In water samples, ∑chlorinated-OPEs (Cl-OPEs) concentrations exceeded ∑non-chlorinated-OPEs (non-Cl-OPEs) with median concentrations of 10 ng L-1 and 1.3 ng L-1, respectively. In sediment samples, ∑Cl-OPEs and ∑nonchlorinated-OPEs had median concentrations of 4.5 and 2.5 ng g-1, respectively. High concentrations of OPEs in samples from the Mackenzie River plume suggest riverine discharge as an OPE source to the Canadian Arctic. The prevalence of OPEs at other sites is consistent with long-range transport. The OPE inventory of the Canadian Arctic Ocean representative of years 2013-2018 was estimated at 450-16,000 tonnes with a median ∑11OPE mass of 4100 tonnes with >99% of the OPE inventory estimated to be in the water column. These results highlight the importance of OPEs as water-based Arctic contaminants subject to long-range transport and local sources. The high OPE inventory in the water column of the Canadian Arctic Ocean points to the need for international regulatory mechanisms for persistent and mobile organic contaminants (PMOCs) that are not covered by the risk assessment criteria of the Stockholm Convention.

Canadian Arctic Contaminants and Their Effects on the Maternal Brain and Behaviour: A Scoping Review of the Animal Literature.

Background: Environmental toxicants such as methylmercury, polychlorinated biphenyls, and organochlorine pesticides are potentially harmful pollutants present in contaminated food, soil, air, and water. Exposure to these ecologically relevant toxicants is prominent in Northern Canadian populations. Previous work focused on toxicant exposure during pregnancy as a threat to fetal neurodevelopment. However, little is known about the individual and combined effects of these toxicants on maternal health during pregnancy and post-partum. Methods: A scoping review was conducted to synthesize the current knowledge regarding individual and combined effects of methylmercury, polychlorinated biphenyls, and organochlorine pesticides on maternal behaviour and the maternal brain. Relevant studies were identified through the PubMed, Embase, and Toxline databases. Literature involving animal models and one human cohort were included in the review. Results: Research findings indicate that exposures to these environmental toxicants are associated with neurochemical changes in rodent models. Animal models provided the majority of information on toxicant-induced alterations in maternal care behaviours. Molecular and hormonal changes hypothesized to underlie these alterations were also addressed, although studies assessing toxicant co-exposure were limited. Conclusion: This review speaks to the limited knowledge regarding effects of these persistent organic pollutants on the maternal brain and related behavioural outcomes. Further research is required to better comprehend any such effects on maternal brain and behaviour, as maternal care is an important contributor to offspring neurodevelopment.

Levels and trends of current-use pesticides (CUPs) in the arctic: An updated review, 2010–2018

Abstract Global regulations and many regional and national controls restrict the use of substances that exhibit the potential for environmental persistence and long-range transport. Nevertheless, many current-use pesticides (CUPs) continue to be newly discovered in remote regions, including the Arctic. The present review serves as an update, summarizing newly available information for CUPs in the Arctic environment and biota published from 2010 to 2018. Since 2010, at least seven new CUPs have been measured in Arctic media: 2-methyl-4- chlorophenoxyacetic acid (MCPA), metribuzin, pendimethalin, phosalone, quizalofop-ethyl, tefluthrin and triallate. Considering the large number of pesticides in current use, the number measured in the Arctic is very limited, however, modelling studies have identified additional CUPs as potential Arctic contaminants that have yet to be investigated in the Arctic. Owing to their recent detection, reports of CUPs in the Arctic are limited, but growing. CUPs have been reported in a wide range of abiotic Arctic matrices, including air, snow, ice, freshwater and seawater, indicating their capacity for long-range atmospheric transport, however, concentrations are generally low in comparison to legacy pesticides and other persistent organic pollutants (POPs). Recent food-web studies indicate CUPs can enter Arctic terrestrial and marine food chains, however, in contrast to POPs, the highest concentrations of many CUPs were found in lower trophic-level organisms, and the lowest concentrations detected in animals at the highest trophic levels (i.e, ringed seals, polar bear, caribou, and wolves) indicating significant trophic dilution. The detection of CUPs in the remote Arctic ecosystem reinforces the need for continued monitoring of both known and potential Arctic pollutants to prevent impacts on human and environmental health as the global arsenal of pesticides used in agriculture continuously changes.

Short-term monitoring of Arctic trace metal contamination based on Cetrariella delisei bioindicator in Svalbard

This study focuses on short-term monitoring of trace metals in the Svalbard archipelago. Short-term studies using lichen bioindicators are important because temporary changes in lichen trace metal levels are mainly dependent on air pollutants. Here, we investigated temporal and spatial differences in the content of trace metals such as Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, and Zn measured in the lichen thalli of &lt;em&gt;Cetrariella delisei&lt;/em&gt;. The temporal aspect was studied in the marine plain of Calypsostranda between 1988 and 2016 and that of Hornsundneset between 1985 and 2008. The spatial aspect was studied between Hornsundneset in 1985 and Calypsostranda in 1988 as well as between Hornsundneset in 2008 and Calypsostranda in 2016. The results revealed an increase in the concentration of Cr, Mn, Ni, and Co for both the aspects, while a decrease in the contents of Cu, Cd, and Mo was observed. Pb content varied, as Pb level increased with time in Hornsundneset but decreased in Calypsostranda. The Zn content showed no significant changes in both temporal and spatial aspects.

Environmental characteristics of a tundra river system in Svalbard. Part 2: Chemical stress factors

Bacterial communities in the Arctic environment are subject to multiple stress factors, including contaminants, although typically their concentrations are small. The Arctic contamination research has focused on persistent organic pollutants (POPs) because they are bioaccumulative, resistant to degradation and toxic for all organisms. Pollutants have entered the Arctic predominantly by atmospheric and oceanic long-range transport, and this was facilitated by their volatile or semi-volatile properties, while their chemical stability extended their lifetimes following emission. Chemicals present in the Arctic at detectable and quantifiable concentrations testify to their global impact. Chemical contamination may induce serious disorders in the integrity of polar ecosystems influencing the growth of bacterial communities. In this study, the abundance and the types of bacteria in the Arctic freshwater were examined and the microbial characteristics were compared to the amount of potentially harmful chemical compounds in particular elements of the Arctic catchment. The highest concentrations of all determined PAHs were observed in two samples in the vicinity of the estuary both in June and September 2016 and were 1964 ng L−1 (R12) and 3901 ng L−1 (R13) in June, and 2179 ng L−1 (R12) and 1349 ng L−1 (R13) in September. Remarkable concentrations of the sum of phenols and formaldehyde were detected also at the outflow of the Revelva river into the sea (R12) and were 0.24 mg L−1 in June and 0.35 mg L−1 in September 2016. The elevated concentrations of chemical compounds near the estuary suggest a potential impact of the water from the lower tributaries (including the glacier-fed stream measured at R13) or the sea currents and the sea aerosol as pollutant sources. The POPs' degradation at low temperature is not well understood but bacteria capable to degrading such compounds were noted in each sampling point.

Prenatal exposure to an environmentally relevant mixture of Canadian Arctic contaminants decreases male reproductive function in an aging rat model

Elevated levels of organochlorines (OC) have been reported in Inuit populations in the Arctic. We hypothesized that prenatal exposure to a Canadian Arctic OC mixture adversely affects male reproductive function and health with age. Sprague-Dawley female rats (F0) were gavaged with an environmentally relevant concentration of an Arctic OC mixture or corn oil (Control) during mating with untreated males until parturition (F1 litters). After postnatal day (PND) 90, the weights of the OC F1 males differed dramatically relative to Controls (P<0.05; n=10) and they exhibited respiratory distress. Except for possible thinning of the alveolar barrier, histological observation of the lungs revealed no apparent pathology to explain the respiratory distress. At PND 365, OC F1 males had reduced relative reproductive organ weights and lower sperm quality than Controls (P<0.05). At PND 90, OC F1 males were subfertile (P<0.05), but were infertile at PND 365. In conclusion, environmentally relevant prenatal OC exposure reduced reproductive function and health in aging male rats, providing new insight into the effects of early-life exposures to these contaminants.

Predicted persistence and response times of linear and cyclic volatile methylsiloxanes in global and local environments

We investigated the response times of eight volatile methylsiloxanes (VMSs) in environmental systems at different scales from local to global, with a particular focus on overall loss rates after cessation of emissions. In part, this is driven by proposals to restrict the use of some of these compounds in certain products in Europe. The GloboPOP model estimated low absolute Arctic Contamination Potentials for all VMSs and rapid response times in all media except sediment. VMSs are predicted to be distributed predominantly in air where they react with OH radicals, leading to short response times. After cessation of emissions VMSs concentrations in the environment are expected to decrease rapidly from current levels. Response times in specific water and sediment systems were evaluated using a dynamic QWASI model. Response times were sensitive to both physico-chemical properties and environmental characteristics. Degradation was predicted to play the most important role in determining response times in water and sediment. In the case of the lowest molecular weight VMSs such as L2 and D3, response times were essentially independent of environmental characteristics due to fast hydrolysis in water and sediment. However, response times for the other VMSs are system-specific. They are relatively short in shallow water bodies but increase with depth due to the diminishing role of volatilization on concentration change as volume to surface area ratio increases. In sediment, degradation and resuspension rates also contribute most to the response times. The estimated response times for local environments are useful for planning future monitoring programs.

Legacy and new halogenated persistent organic pollutants in polar bears from a contamination hotspot in the Arctic, Hudson Bay Canada

A large and complex suite of 295 legacy and new halogenated persistent organic pollutants (POPs) were investigated in fat or liver tissue samples of polar bears collected in 2013–2014 from Southern (SHB) and Western (WHB) subpopulations of the Canadian Arctic contaminants hotspot of Hudson Bay. A total of 210 POPs were detected and/or quantifiable with some frequency in all fat or liver samples. POP profile and concentration differences were investigated both within (e.g. age and sex) and between the two subpopulations. Two time-point comparisons were made relative to POPs reported for Hudson Bay polar bears harvested in 2007–2008. ΣPolychlorinated biphenyl (PCB) concentrations at both time points were the most concentrated of the POP groups, and were spatially uniform with no detectable influence of sex or age, as were concentrations of the dominant congener CB153. ΣChlordanes (ΣCHLs, 74–79% oxychlordane) and the Σperfluoroalkyl substances (ΣPFASs, ≈60% perfluorooctane sulfonate (PFOS)) had the second greatest POP group concentrations in SHB and WHB respectively, with ΣPFASs and ΣCHLs being significantly influenced by age and/or sex. ΣCHLs were spatially uniform but ΣPFASs were greater in the SHB bears, as were e.g. some flame retardants, due to e.g. local contamination and/or changes in bear behavior and diet. Endosulfans and hexabromocyclododecane were detectable in samples from 2007–2008 but not from 2013–2014, which is consistent with their global POP regulations. ΣPolychlorinated naphthalenes (ΣPCNs) were consistently detected at relatively high concentrations compared to other arctic wildlife, however these concentrations were low relative to legacy POPs. ΣShort-chain chlorinated paraffins (ΣSCCPs) were major contributors to the overall POPs burden with concentrations comparable to other legacy POPs, though there was no significant difference between or within subpopulations for PCNs or SCCPs. Except for octachlorostyrene, POPs concentrations were generally lower in female and male bears from SHB in 2013–2014 relative to 2007–2008, however those of WHB males were greater over the same timeframe for almost all POPs.

North Atlantic Deep Water formation inhibits high Arctic contamination by continental perfluorooctane sulfonate discharges

AbstractPerfluorooctane sulfonate (PFOS) is an aliphatic fluorinated compound with eight carbon atoms that is extremely persistent in the environment and can adversely affect human and ecological health. The stability, low reactivity, and high water solubility of PFOS combined with the North American phaseout in production around the year 2000 make it a potentially useful new tracer for ocean circulation. Here we characterize processes affecting the lifetime and accumulation of PFOS in the North Atlantic Ocean and transport to sensitive Arctic regions by developing a 3‐D simulation within the MITgcm. The model captures variability in measurements across biogeographical provinces (R2 = 0.90, p = 0.01). In 2015, the North Atlantic PFOS reservoir was equivalent to 60% of cumulative inputs from the North American and European continents (1400 Mg). Cumulative inputs to the Arctic accounted for 30% of continental discharges, while the remaining 10% was transported to the tropical Atlantic and other regions. PFOS concentrations declined rapidly after 2002 in the surface mixed layer (half‐life: 1–2 years) but are still increasing below 1000 m depth. During peak production years (1980–2000), plumes of PFOS‐enriched seawater were transported to the sub‐Arctic in energetic surface ocean currents. However, Atlantic Meridional Overturning Circulation (AMOC) and deep ocean transport returned a substantial fraction of this northward transport (20%, 530 Mg) to southern latitudes and reduced cumulative inputs to the Arctic (730 Mg) by 70%. Weakened AMOC due to climate change is thus likely to increase the magnitude of persistent bioaccumulative pollutants entering the Arctic Ocean.

Screening-level exposure-based prioritization to identify potential POPs, vPvBs and planetary boundary threats among Arctic contaminants

Abstract A report that reviews Arctic contaminants that are not currently regulated as persistent organic pollutants (POPs) under international treaties was recently published by the Arctic Monitoring and Assessment Programme (AMAP). We evaluated 464 individual chemicals mentioned in the AMAP report according to hazard profiles for POPs, very persistent and very bioaccumulative (vPvB) chemicals, and two novel and distinct hazard profiles we derived from the planetary boundary threat framework. The two planetary boundary threat profiles assign high priority to chemicals that will be mobile and poorly reversible environmental contaminants. Utilizing persistence as a proxy for poor reversibility, we defined two exposure-based hazard profiles; airborne persistent contaminants (APCs) and waterborne persistent contaminants (WPCs) that are potential planetary boundary threats. We used in silico estimates of physicochemical properties and multimedia models to calculate hazard metrics for persistence, bioaccumulation and long-range transport potential, then we synthesized this information into four exposure-based hazard scores of the potential of each AMAP chemical to fit each of the POP, vPvB, APC and WPC exposure-based hazard profiles. As an alternative to adopting a “bright line” score that represented cause for concern, we scored the AMAP chemicals by benchmarking against a reference set of 148 known and relatively well-studied contaminants and expressed their exposure-based hazard scores as percentile ranks against the scores of the reference set chemicals. Our results show that scores in the four exposure-based hazard profiles provide complementary information about the potential environmental exposure-based hazards of the AMAP chemicals. Our POP, vPvB, APC and WPC exposure-based hazard scores identify high priority chemicals for further study from among the AMAP contaminants.

Using Domestic and Free-Ranging Arctic Canid Models for Environmental Molecular Toxicology Research.

The use of sentinel species for population and ecosystem health assessments has been advocated as part of a One Health perspective. The Arctic is experiencing rapid change, including climate and environmental shifts, as well as increased resource development, which will alter exposure of biota to environmental agents of disease. Arctic canid species have wide geographic ranges and feeding ecologies and are often exposed to high concentrations of both terrestrial and marine-based contaminants. The domestic dog (Canis lupus familiaris) has been used in biomedical research for a number of years and has been advocated as a sentinel for human health due to its proximity to humans and, in some instances, similar diet. Exploiting the potential of molecular tools for describing the toxicogenomics of Arctic canids is critical for their development as biomedical models as well as environmental sentinels. Here, we present three approaches analyzing toxicogenomics of Arctic contaminants in both domestic and free-ranging canids (Arctic fox, Vulpes lagopus). We describe a number of confounding variables that must be addressed when conducting toxicogenomics studies in canid and other mammalian models. The ability for canids to act as models for Arctic molecular toxicology research is unique and significant for advancing our understanding and expanding the tool box for assessing the changing landscape of environmental agents of disease in the Arctic.