High genetic load without purging in caribou, a diverse species at risk.

High intra-specific genetic diversity is associated with adaptive potential, which is key for resilience to global change. However, high variation may also support deleterious alleles through genetic load, thereby increasing the risk of inbreeding depression if population sizes decrease. Purging of deleterious variation has been demonstrated in some threatened species.

Human biomonitoring of dioxins, furans, and non-ortho dioxin-like polychlorinated biphenyls (PCBs) in blood plasma from Old Crow, Yukon, Canada (2019).

Dioxins, furans, and dioxin-like polychlorinated biphenyls (PCBs) are a group of persistent and toxic chemicals that are known to have human health effects at low levels. These chemicals have been produced for commercial use (PCBs) or unintentionally as by-products of industry or natural processes (PCBs, dioxins, and furans). Additionally, dioxin-like PCBs were formerly used in electrical applications before being banned internationally (2004).

Hexachlorobenzene and omega-3 fatty acid intake from traditional foods in the northern Yukon: A risk and benefit analysis.

A human biomonitoring study was conducted in the community of Old Crow, Yukon, in 2019, finding that levels of hexachlorobenzene (HCB) in plasma were elevated in the community relative to the general Canadian population. The aim of this study was to estimate dietary intake of both hexachlorobenzene, and the nutrient omega-3 fatty acids from locally harvested traditional foods in Old Crow, with the aim of identifying possible regional sources of exposure. A stochastic model was constructed to estimate intake of both hexachlorobenzene and the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

Mercury bioaccessiblity in freshwater fish species from northern Canada.

Indigenous communities in northern Canada rely on locally harvested traditional foods, including fish, which provides them with nutritional, cultural, and social benefits. However, mercury exposure from fish consumption can pose a health risk for populations that consume large amounts of fish with elevated mercury concentrations. The bioaccessiblity of mercury in the tissue of northern Canadian freshwater fish is not yet known.

Contributions and perspectives of Indigenous Peoples to the study of mercury in the Arctic.

Arctic Indigenous Peoples are among the most exposed humans when it comes to foodborne mercury (Hg). In response, Hg monitoring and research have been on-going in the circumpolar Arctic since about 1991; this work has been mainly possible through the involvement of Arctic Indigenous Peoples. The present overview was initially conducted in the context of a broader assessment of Hg research organized by the Arctic Monitoring and Assessment Programme.

Temporal trends of mercury in Arctic biota: 10 more years of progress in Arctic monitoring.

Temporal trend analysis of (total) mercury (THg) concentrations in Arctic biota were assessed as part of the 2021 Arctic Monitoring and Assessment Programme (AMAP) Mercury Assessment. A mixed model including an evaluation of non-linear trends was applied to 110 time series of THg concentrations from Arctic and Subarctic biota. Temporal trends were calculated for full time series (6-46 years) and evaluated with a particular focus on recent trends over the last 20 years.

Perfluoroalkyl substances in circum-ArcticRangifer: caribou and reindeer.

Livers of caribou and reindeer (Rangifer tarandus) from Canada (n = 146), Greenland (n = 30), Svalbard (n = 7), and Sweden (n = 60) were analyzed for concentrations of eight perfluoroalkyl carboxylic acids and four perfluoroalkane sulfonic acids. In Canadian caribou, PFNA (range < 0.01-7.

Temporal change and the influence of climate and weather factors on mercury concentrations in Hudson Bay polar bears, caribou, and seabird eggs.

Temporal trends of mercury in Arctic wildlife are inconsistent within and between species and are often insignificant, which limits data interpretation. Recent multivariate analyses have shown that weather and climate factors (e.g.

Population dynamics of caribou shaped by glacial cycles before the last glacial maximum.

Pleistocene glacial cycles influenced the diversification of high-latitude wildlife species through recurrent periods of range contraction, isolation, divergence, and expansion from refugia and subsequent admixture of refugial populations. We investigate population size changes and the introgressive history of caribou (Rangifer tarandus) in western Canada using 33 whole genome sequences coupled with larger-scale mitochondrial data. We found that a major population expansion of caribou occurred starting around 110,000 years ago (kya), the start of the last glacial period.

Biomarkers of poly- and perfluoroalkyl substances (PFAS) in Sub-Arctic and Arctic communities in Canada.

Polyfluoroalkyl substances and perfluoroalkyl substances (PFAS) are a family of anthropogenic chemicals that are used in food packaging, waterproof clothing, and firefighting foams for their water and oil resistant properties. Though levels of some PFAS appear to be decreasing in Canada's south, environmental levels have been increasing in the Arctic due to long-range transport. However, the implications of this on human exposures in sub-Arctic and Arctic populations in Canada have yet to be established.

Human biomonitoring results of contaminant and nutrient biomarkers in Old Crow, Yukon, Canada.

Several large-scale human biomonitoring projects have been conducted in Canada, including the Canadian Health Measures Survey (CHMS) and the First Nations Biomonitoring Initiative (FNBI). However, neither of these studies included participants living in the Yukon. To address this data gap, a human biomonitoring project was implemented in Old Crow, a fly-in Gwich'in community in the northern Yukon.

Renal trace elements in barren-ground caribou subpopulations: Temporal trends and differing effects of sex, age and season.

Caribou (Rangifer tarandus) are a culturally significant food resource for communities in northern Canada and Greenland. Many barren-ground caribou subpopulations are currently in decline, some dramatically; understanding the influence of stressors, such as toxic trace metals, is important. These contaminants enter Arctic terrestrial environments via atmospheric transport from industrialized areas and from local sources, accumulating there in the environment.

Measurements of cesium in Arctic beluga and caribou before and after the Fukushima accident of 2011.

Concern from northern communities following the Fukushima Daiichi nuclear accident of March 2011 has prompted a reassessment of the safety of their traditional foods with respect to radioactivity levels. To this end, a study was conducted to measure the levels of radionuclides in Arctic caribou (Rangifer tarandus) and beluga (Delphinapterus leucas). The main radionuclide of concern is cesium-137, which is easily transferred through the lichen-caribou food chain.

Cadmium and other elements in tissues from four ungulate species from the Mackenzie Mountain region of the Northwest Territories, Canada.

Tissue samples from four ungulate species from the south Mackenzie Mountain region of the Northwest Territories (NT), Canada, were analysed for stable and radioactive elements and (15)N and (13)C stable isotopes. Elevated Cd concentrations in moose (Alces americanus) kidney have been observed in the region and are a health care concern for consumers of traditional foods. This study examined the factors associated with, and potential renal effects from, the accumulation of cadmium, and interactions with other elements in four sympatric ungulate species.

Contaminants in two West Greenland caribou populations.

Two caribou populations in West Greenland were sampled and the kidneys, liver and muscle analyzed for contaminants, including aluminum, arsenic, cadmium, copper, lead, mercury, selenium and zinc. Although close in proximity, the two populations are topographically separated by an ice cap, which creates different climates and vegetation types in each region. Contaminant levels reflected the differing diets of the two caribou populations.

Mercury in freshwater ecosystems of the Canadian Arctic: recent advances on its cycling and fate.

The Canadian Arctic has vast freshwater resources, and fish are important in the diet of many Northerners. Mercury is a contaminant of concern because of its potential toxicity and elevated bioaccumulation in some fish populations. Over the last decade, significant advances have been made in characterizing the cycling and fate of mercury in these freshwater environments.

Mercury in the Canadian Arctic terrestrial environment: an update.

Contaminants in the Canadian Arctic have been studied over the last twenty years under the guidance of the Northern Contaminants Program. This paper provides the current state of knowledge on mercury (Hg) in the Canadian Arctic terrestrial environment. Snow, ice, and soils on land are key reservoirs for atmospheric deposition and can become sources of Hg through the melting of terrestrial ice and snow and via soil erosion.

Biomagnification of perfluorinated compounds in a remote terrestrial food chain: Lichen-Caribou-wolf.

The biomagnification behavior of perfluorinated carboxylates (PFCAs) and perfluorinated sulfonates (PFSAs) was studied in terrestrial food webs consisting of lichen and plants, caribou, and wolves from two remote northern areas in Canada. Six PFCAs with eight to thirteen carbons and perfluorooctane sulfonate (PFOS) were regularly detected in all species. Lowest concentrations were found for vegetation (0.

Assessing risk of mercury exposure and nutritional benefits of consumption of caribou (Rangifer tarandus) in the Vuntut Gwitchin First Nation community of Old Crow, Yukon, Canada.

The contamination of traditional foods with chemical pollutants is a challenge to the food security of Aboriginal Peoples. Mercury levels are generally low in terrestrial animals; however renal mercury levels have been shown to change over time in the Porcupine Caribou Herd, the principal food source for the Vuntut Gwitchin First Nation of Old Crow in Yukon, Canada. Seventy-five Porcupine Caribou muscle, sixty-three kidney and three liver samples were analyzed for total mercury.

Temporal trends of Hg in Arctic biota, an update.

A statistically robust method was applied to 83 time-series of mercury in Arctic biota from marine, freshwater and terrestrial ecosystems with the purpose of generating a 'meta-analysis' of temporal trend data collected over the past two to three decades, mostly under the auspices of the Arctic Monitoring and Assessment Program (AMAP). Sampling locations ranged from Alaska in the west to northern Scandinavia in the east. Information from recently published temporal trend studies was tabulated to supplement the results of the statistical analyses.

Temporal and geographic trends in trace element concentrations in moose from Yukon, Canada.

The Yukon Contaminants Committee has conducted a hunter survey since 1994, annually requesting tissue samples from successful moose hunters in the Yukon. Moose kidney, liver and muscle tissue were analyzed for arsenic, cadmium, chromium, cobalt, copper, lead, mercury, molybdenum, selenium and zinc. Levels of most trace elements measured were not of concern toxicologically or in terms of deficiencies.

Effects of mercury on neurochemical receptor-binding characteristics in wild mink.

Piscivorous wildlife, such as mink (Mustela vison), routinely are exposed to mercury (Hg) in their natural environment at levels that may cause adverse behavioral outcomes. The purpose of this study was to determine if a correlation exists between neurochemical receptors and concentrations of Hg in the brains of wild mink. Specifically, receptor-binding assays were conducted to characterize the muscarinic cholinergic (mACh) and dopaminergic-2 (D2) systems in brain tissues collected from mink trapped in the Yukon Territory, Ontario, and Nova Scotia (Canada), and values were correlated with total Hg and methyl Hg (MeHg) concentrations in the brains.

Spatial and temporal trends of contaminants in terrestrial biota from the Canadian Arctic.

Contaminants in the Canadian Arctic have been studied over the last twelve years under the guidance of the Northern Contaminants Program. This paper summarizes results from that program from 1998 to 2003 with respect to terrestrial animals in the Canadian Arctic. The arctic terrestrial environment has few significant contaminant issues, particularly when compared with freshwater and marine environments.

Cadmium, mercury and selenium concentrations in mink (Mustela vison) from Yukon, Canada.

Mercury (total and methyl), cadmium and selenium concentrations were measured in liver, kidney and brain tissue from mink trapped from the Yukon Territory from 2001-2002. None of these metals was found at levels of toxicological concern. Total mercury averaged 0.

Contaminant residue levels in arctic wolves (Canis lupus) from the Yukon Territory, Canada.

Kidney, liver and bone samples were taken from 19 wolves (Canis lupus) collected from two locations in the Yukon Territory. Liver samples pooled by age and sex were analyzed for 22 organochlorine pesticides and 101 PCB congeners. Individual kidney and liver samples were analyzed for arsenic, cadmium, copper, lead, total mercury, selenium and zinc.