In the Arctic Ocean's southern Beaufort Sea (SB), the length of the sea ice melt season (i.e., period between the onset of sea ice break-up in summer and freeze-up in fall) has increased ...substantially since the late 1990s. Historically, polar bears (Ursus maritimus) of the SB have mostly remained on the sea ice year-round (except for those that came ashore to den), but recent changes in the extent and phenology of sea ice habitat have coincided with evidence that use of terrestrial habitat is increasing. We characterized the spatial behavior of polar bears spending summer and fall on land along Alaska's north coast to better understand the nexus between rapid environmental change and increased use of terrestrial habitat. We found that the percentage of radiocollared adult females from the SB subpopulation coming ashore has tripled over 15 years. Moreover, we detected trends of earlier arrival on shore, increased length of stay, and later departure back to sea ice, all of which were related to declines in the availability of sea ice habitat over the continental shelf and changes to sea ice phenology. Since the late 1990s, the mean duration of the open-water season in the SB increased by 36 days, and the mean length of stay on shore increased by 31 days. While on shore, the distribution of polar bears was influenced by the availability of scavenge subsidies in the form of subsistence-harvested bowhead whale (Balaena mysticetus) remains aggregated at sites along the coast. The declining spatio-temporal availability of sea ice habitat and increased availability of human-provisioned resources are likely to result in increased use of land. Increased residency on land is cause for concern given that, while there, bears may be exposed to a greater array of risk factors including those associated with increased human activities.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Dramatic environmental shifts are occuring throughout the Arctic from climate change, with consequences for the cycling of mercury (Hg). This review summarizes the latest science on how climate ...change is influencing Hg transport and biogeochemical cycling in Arctic terrestrial, freshwater and marine ecosystems. As environmental changes in the Arctic continue to accelerate, a clearer picture is emerging of the profound shifts in the climate and cryosphere, and their connections to Hg cycling. Modeling results suggest climate influences seasonal and interannual variability of atmospheric Hg deposition. The clearest evidence of current climate change effects is for Hg transport from terrestrial catchments, where widespread permafrost thaw, glacier melt and coastal erosion are increasing the export of Hg to downstream environments. Recent estimates suggest Arctic permafrost is a large global reservoir of Hg, which is vulnerable to degradation with climate warming, although the fate of permafrost soil Hg is unclear. The increasing development of thermokarst features, the formation and expansion of thaw lakes, and increased soil erosion in terrestrial landscapes are increasing river transport of particulate-bound Hg and altering conditions for aquatic Hg transformations. Greater organic matter transport may also be influencing the downstream transport and fate of Hg. More severe and frequent wildfires within the Arctic and across boreal regions may be contributing to the atmospheric pool of Hg. Climate change influences on Hg biogeochemical cycling remain poorly understood. Seasonal evasion and retention of inorganic Hg may be altered by reduced sea-ice cover and higher chloride content in snow. Experimental evidence indicates warmer temperatures enhance methylmercury production in ocean and lake sediments as well as in tundra soils. Improved geographic coverage of measurements and modeling approaches are needed to better evaluate net effects of climate change and long-term implications for Hg contamination in the Arctic.
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•Current evidence indicates climate change is influencing Hg cycling in the Arctic.•Permafrost thaw, glacier melt, and coastal erosion are increasing Hg export.•Arctic permafrost is a global Hg reservoir, vulnerable to degradation and release.•Experiments show warmer temperatures increase MeHg in Arctic sediments and soils.•Net effects of climate change on Arctic Hg contamination remain poorly resolved.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We evaluated total mercury (THg) concentrations and trends in polar bears from the southern Beaufort Sea subpopulation from 2004 to 2011. Hair THg concentrations ranged widely among individuals from ...0.6 to 13.3 μg g–1 dry weight (mean: 3.5 ± 0.2 μg g–1). Concentrations differed among sex and age classes: solitary adult females ≈ adult females with cubs ≈ subadults > adult males ≈ yearlings > cubs-of-the-year ≈ 2 year old dependent cubs. No variation was observed between spring and fall samples. For spring-sampled adults, THg concentrations declined by 13% per year, contrasting recent trends observed for other Western Hemispheric Arctic biota. Concentrations also declined by 15% per year considering adult males only, while a slower, nonsignificant decrease of 4.4% per year was found for adult females. Lower THg concentrations were associated with higher body mass index (BMI) and higher proportions of lower trophic position food resources consumed. Because BMI and diet were related, and the relationship to THg was strongest for BMI, trends were re-evaluated adjusting for BMI as the covariate. The adjusted annual decline was not significant. These findings indicate that changes in foraging ecology, not declining environmental concentrations of mercury, are driving short-term declines in THg concentrations in southern Beaufort Sea polar bears.
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IJS, KILJ, NUK, PNG, UL, UM
The monitoring of legacy persistent organic pollutants (POPs) in blubber of key sentinel marine mammal species has been conducted using established techniques for decades. Although these methods for ...polychlorinated biphenyl (PCB) and organochlorine (OC) pesticide determination provide accurate and reproducible results, they possess some drawbacks in terms of cost, time, and a need for large volumes of toxic solvents. QuEChERS (quick, easy, cheap, effective, rugged, and safe) extractions may help address these issues, but have not been applied to marine mammal blubber/adipose. As such, our aim was to develop, validate, and apply a QuEChERS method for the extraction of PCB and OC contaminants in marine mammal blubber. First, we tested multiple solid-phase extraction and clean-up steps to find the approach that provided the cleanest extracts along with consistent and acceptable analyte recovery, accuracy, and precision. QuEChERS extractions followed by two enhanced matrix removal-lipid (EMR-lipid), one primary-secondary amine (PSA), and one silica gel clean-up showed the highest matrix removal and acceptable recoveries of spiked internal (62–97%) and external standards (61–94%). Solvent usage was reduced by ∼393% and extraction time was reduced by ∼25% (from 16 to 12 h). Next, the method was validated using standard reference material (SRM) NIST 1945. Recovery experiments on SRM (n = 5) showed acceptable recovery for 76% and 77% of PCBs and OC pesticides, respectively, and high precision for 73% and 69% of PCBs and OCs, respectively. Finally, the method was used on a set of southeast Greenland killer whales (n = 13), with previously published PCB and OC data. Bland-Altman plots indicated good agreement between QuEChERS and current-use methods for ΣPCBs and some OCs with no significant constant or proportional bias. These results demonstrate that this QuEChERS extraction method represents an effective, lower cost alternative to current-use extractions for PCBs and OCs in blubber, and likely other high-lipid samples.
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•QuEChERS method developed for extraction of persistent organic pollutants in blubber.•The method was validated using a NIST blubber standard reference material.•Method was applied to killer whales previously extracted by typical approaches.•Strong agreement between QuEChERS and current-use methods for most POPs.•The QuEChERS method reduces cost, time, and solvent-use.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Sightings of killer whales (Orcinus orca) in Greenland have increased in recent years, coincident with sea ice loss. These killer whales are likely from fish-feeding North Atlantic populations, but ...may have access to marine mammal prey in Greenlandic waters, which could lead to increased exposures to biomagnifying contaminants. Most studies on polychlorinated biphenyl (PCB) and organochlorine (OC) contaminants in killer whales have used biopsies which may not be representative of contaminant concentrations through the entire blubber depth. Here, we measured PCB and OC concentrations in 10 equal-length blubber sections of 18 killer whales harvested in southeast Greenland (2012–2014), and 3 stranded in the Faroe Islands (2008) and Denmark (2005). Overall, very high concentrations of ΣPCB, Σchlordanes (ΣCHL), and Σdichlorodiphenyltrichloroethane (ΣDDT) were found in the southeast Greenland and Denmark individuals (means of ~40 to 70mgkg−1 lipid weight). These concentrations were higher than in the Faroe Island individuals (means of ~2 to 5mgkg−1 lipid weight) and above those previously reported for other fish-feeding killer whales in the North Atlantic, likely in part due to additional feeding on marine mammals. On a wet weight basis, concentrations of all contaminants were significantly lower in the outermost blubber layer (0.15–0.65cm) compared to all other layers (p<0.01), except for Σhexachlorocyclohexanes. However, after lipid correction, no variation was found for ΣCHL and Σchlorobenzene concentrations, while the outermost layer(s) still showed significantly lower ΣPCB, ΣDDT, Σmirex, Σendosulfan, and dieldrin concentrations than one or more of the inner layers. Yet, the magnitude of these differences was low (up to 2-fold) suggesting that a typical biopsy may be a reasonable representation of the PCB and OC concentrations reported in killer whales, at least on a lipid weight basis.
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•POP levels in Greenland orcas may be due to feeding both on fish and marine mammals.•Levels of POPs decreased from sub-adults>adult males>adult females>fetuses.•Limited variation found in lipid weight POP levels among full-depth blubber layers•Biopsies may be a reasonable representation of POP levels in killer whale blubber.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Traditional foods provide nutritional, social, and economic benefits for Indigenous communities; however, anthropogenic activities have raised concerns about mercury (Hg), especially methylmercury ...(MeHg), in these foods. This issue may be of particular concern for communities near large industrial activities, including the Bigstone Cree Nation adjacent to the Athabasca oil sands region, Canada. This community-led study sought to assess variation in THg and MeHg concentrations among traditional food types (plants or animals), species, and tissues (muscles, organs), and variation in concentrations of the micronutrient selenium (Se)— thought to protect against Hg toxicity—and Se:THg ratios. Thirteen plant and animal species were collected in 2015 by Bigstone Cree community members. We quantified THg, Se, and Se:THg ratios in 65 plant and 111 animal samples and MeHg in 106 animal samples. For plants, the lichen, old man’s beard (Usnea spp.), showed the highest concentrations of THg and Se (0.11 ± 0.02 and 0.08 ± 0.01 μg g−1 w. w., respectively) and also had a low Se:THg molar ratio. Concentrations of THg, MeHg, and Se differed among animal samples (P < 0.010), showing variation among species and among tissues/organs. Generally, concentrations of THg and MeHg were highest in aquatic animals, which also had relatively low Se:THg molar ratios. Overall results revealed substantial variation in the patterns of THg, MeHg, Se and Se:THg ratios across this comprehensive basket of traditional foods. Thus, measuring concentrations of THg alone, without considering MeHg and potential associations with Se, may not adequately convey the exposure to Hg in traditional foods.
•Hg and Se were measured in traditional foods in the Athabasca region, Canada.•Total Hg (THg) and Se were detected in all plant and animal samples.•Methylmercury (MeHg) was measured and detected in most animal tissues and organs.•THg, and also Se:Hg molar ratios, were generally higher in animals than in plants.•THg and MeHg were higher in aquatic animals than in terrestrial animals.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Flame retardants (FRs) are commonly added to commercial products to achieve flammability resistance. Since most of them are not chemically bonded to the materials, they could be leached to the ...environment during the production and disposal cycle. These FRs were categorised based on their chemical nature, including brominated, organophosphorus-, mineral- and nitrogen-based. This review summarised the abiotic degradation reactions of these four classes of FRs, with a focus on thermal and photodegradation reactions in environmental and food matrices. Only 24 papers have reported related information on abiotic degradation reactions that could be useful for predicting possible degradation pathways, and most focused on brominated FRs. Most studies also investigated the thermal degradation of FRs under high temperatures (>400 °C), which exceeds the normal cooking temperature at 100-300 °C. For photodegradation, studies have used up to five times the energy typically used in UV radiation during food processing. It is recommended that future studies investigate the fate of these FRs in foods under more realistic processing conditions, to provide a more comprehensive picture of the estimated consumption of FRs and their degradation products from foods, and facilitate a better risk assessment of the use of these novel FRs.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Rising global demand for energy promotes extensive mining of natural resources, such as oil sands extractions in Alberta, Canada. These extractive activities release hazardous chemicals into the ...environment, such as polycyclic aromatic compounds (PACs), which include the parent polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, and sulfur-containing heterocyclic dibenzothiophenes (DBTs). In areas adjacent to industrial installations, Indigenous communities may be exposed to these PACs through the consumption of traditional foods. Our objective was to evaluate and compare the concentrations of total PACs (∑PAC), expressed as the sum of the 16 U.S. EPA priority PAHs (∑PAH), 49 alkylated PAHs (∑alkyl-PAH), and 7 DBTs (∑DBT) in plant and animal foods collected in 2015 by the Bigstone Cree Nation in Alberta, Canada. We analyzed 42 plant tissues, 40 animal muscles, 5 ribs, and 4 pooled liver samples. Concentrations of ∑PAC were higher in the lichen, old man’s beard (Usnea spp.) (808 ± 116 ng g−1 w.w.), than in vascular plants, and were also higher in smoked moose (Alces alces) rib (461 ± 120 ng g−1 w.w.) than in all other non-smoked animal samples. Alkylated-PAHs accounted for between 63% and 95% of ∑PAC, while the concentrations of ∑PAH represented 4%–36% of ∑PAC. Contributions of ∑DBT to ∑PAC were generally lowest, ranging from <1% to 14%. While the concentrations of benzo(a)pyrene (BaP) and ∑PAH4 (∑benzoaanthracene, chrysene, benzobfluoranthene, and BaP) in all samples were below guideline levels for human consumption as determined by the European Commission, guideline levels for the more prevalent alkylated PAHs are not available. Given the predominance of alkylated PAHs in all food samples and the potentially elevated toxicity relative to parent PAHs of this class of PACs, it is critical to consider a broader range of PACs other than just parent PAHs in research conducted close to oil sands mining activities.
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•Benzoapyrene (BaP) was not detected in most of the plant and animal samples.•Alkylated PAHs were the dominant PAC class in all plant and animal samples.•Old man’s beard (a lichen) and smoked moose rib had the highest levels of alkylated PAHs.•Levels of dibenzothiophenes (DBTs) were minor contributors to the total PACs.
Alkylated PAHs were the dominant class of PACs relative to parent PAHs and DBTs in traditional foods of the Bigstone Cree Nation near the Athabasca oil sands in Alberta, Canada.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Two global environmental issues, climate change and contamination by persistent organic pollutants, represent major concerns for arctic ecosystems. Yet, it is unclear how these two stressors interact ...in the Arctic. For instance, the influence of climate-associated changes in food web structure on exposure to pollutants within arctic ecosystems is presently unknown. Here, we report on recent changes in feeding ecology (1991−2007) in polar bears (Ursus maritimus) from the western Hudson Bay subpopulation that have resulted in increases in the tissue concentrations of several chlorinated and brominated contaminants. Differences in timing of the annual sea ice breakup explained a significant proportion of the diet variation among years. As expected from climate change predictions, this diet change was consistent with an increase in the consumed proportions of open water-associated seal species compared to ice-associated seal species in years of earlier sea ice breakup. Our results demonstrate that climate change is a modulating influence on contaminants in this polar bear subpopulation and may pose an additional and previously unidentified threat to northern ecosystems through altered exposures to contaminants.
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IJS, KILJ, NUK, PNG, UL, UM
Accurate diet estimates are necessary to assess trophic interactions and food web dynamics in ecosystems, particularly for apex predators like cetaceans, which can regulate entire food webs. ...Quantitative fatty acid analysis (QFASA) has been used to estimate the diets of marine predators in the last decade but has yet to be implemented on free-ranging cetaceans, from which typically only biopsy samples containing outer blubber are available, due to a lack of empirically determined calibration coefficients (CCs) that account for fatty acid (FA) metabolism. Here, we develop and validate QFASA for killer whales using full blubber from managed-care and free-ranging individuals. First, we compute full, inner, and outer blubber CCs from the FA signatures across the blubber layers of managed-care killer whales and their long-term diet items. We then run cross-validating simulations on the managed-care individuals to evaluate the accuracy of diet estimates by comparing full-depth and depth-specific estimates to true diets. Finally, we apply these approaches to subsistence-harvested killer whales from Greenland to test the utility of the method for free-ranging killer whales, particularly for the outer blubber. Accurate diet estimates for the managed-care killer whales were only achieved using killer whale-specific and blubber-layer-specific CCs. Modeled diets for the Greenlandic killer whales largely consisted of seals (75.9 ± 4.7%) and/or fish (20.4 ± 2.4%), mainly mackerel, which was consistent with stomach content data and limited literature on this population. Given the remote habitats and below surface feeding of most cetaceans, this newly developed cetacean-specific QFASA method, which can be applied to outer-layer biopsies, offers promise to provide a significant new understanding of diet dynamics of free-ranging odontocetes and perhaps other cetacean species throughout the world's oceans.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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