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Whitehorse, Canada

Gamberg M.,Gamberg Consulting | Chetelat J.,Environment Canada | Poulain A.J.,University of Ottawa | Zdanowicz C.,Uppsala University | Zheng J.,Natural Resources Canada
Science of the Total Environment | Year: 2015

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. In the Canadian Arctic, new data have been collected for snow and ice that provide more information on the net accumulation and storage of Hg in the cryosphere. Concentrations of total Hg (THg) in terrestrial snow are highly variable but on average, relatively low (<5ngL-1), and methylmercury (MeHg) levels in terrestrial snow are also generally low (<0.1ngL-1). On average, THg concentrations in snow on Canadian Arctic glaciers are much lower than those reported on terrestrial lowlands or sea ice. Hg in snow may be affected by photochemical exchanges with the atmosphere mediated by marine aerosols and halogens, and by post-depositional redistribution within the snow pack. Regional accumulation rates of THg in Canadian Arctic glaciers varied little during the past century but show evidence of an increasing north-to-south gradient. Temporal trends of THg in glacier cores indicate an abrupt increase in the early 1990s, possibly due to volcanic emissions, followed by more stable, but relatively elevated levels. Little information is available on Hg concentrations and processes in Arctic soils. Terrestrial Arctic wildlife typically have low levels of THg (<5μgg-1 dry weight) in their tissues, although caribou (Rangifer tarandus) can have higher Hg because they consume large amounts of lichen. THg concentrations in the Yukon's Porcupine caribou herd vary among years but there has been no significant increase or decrease over the last two decades. © 2014 Elsevier B.V.

Larter N.C.,Natural Resources Canada | Macdonald C.R.,Northern Environmental Consulting and Analysis | Elkin B.T.,Natural Resources Canada | Wang X.,Environment Canada | And 3 more authors.
Ecotoxicology and Environmental Safety | Year: 2016

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 15N and 13C 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. Mean renal Cd concentration was highest in moose (48.3 mg/kg ww), followed by mountain caribou (Rangifer tarandus caribou) (13.9 mg/kg ww) and mountain goat (Oreamnos americanus) (5.78 mg/kg ww). No local sources of Cd were evident and the elevated levels in moose are considered to be natural in origin. Conversely, total Hg concentration was significantly higher in mountain caribou kidney (0.21 mg/kg ww) than in moose (0.011 mg/kg ww). 134Cs (t1/2=2.1 y) in mountain goat and Dall's sheep (Ovis dalli) muscle is evidence of deposition from the Fukushima reactor accident in 2011. 137Cs (t1/2=30.2 y) in all four ungulates is primarily a remnant of the nuclear weapons tests of the 1960s. The levels of both nuclides are low and the risk to the animals and people consuming them is negligible. Stable isotope δ15N and δ13C signatures in muscle showed a separation between the mountain caribou, with a lichen-dominated diet, and moose, which browse shrubs and forbs. Isotope signatures for mountain goat and Dall's sheep showed generalist feeding patterns. Differences in elemental and radionuclide levels between species were attributed to relative levels of metal accumulation in the different food items in the diets of the respective species. Kidneys from each species showed minor histological changes in the proximal tubule and glomerulus, although glomerular changes were rare and all changes were rare in mountain goat kidney. Kidney function was not expected to be affected in any species. Provisional Monthly Intake recommendations from the WHO indicate that Cd in moose organs will continue to be a public health care concern. However, traditional foods continue to be an important nutritional component of northern diets, particularly in consideration of the shift towards store-bought food. © 2016.

Schuster R.C.,University of Northern British Columbia | Gamberg M.,Gamberg Consulting | Dickson C.,Council of Yukon First Nations | Chan H.M.,University of Northern British Columbia
Environmental Research | Year: 2011

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. Average concentrations were 0.003, 0.360 and 0.120. mg/kg wet weight total mercury for muscle, kidney and liver, respectively. Consumption data of caribou muscle, kidney and liver were collected from twenty-six adults in Vuntut Gwitchin households. Women of child-bearing age (n=5) consumed a median of 71.5. g/person/day of caribou muscle and 0.0. g/person/day kidney but consumed no liver; median consumptions for all other adults (women aged 40+ and all men, n=21) were 75.8, 3.2 and 2.5. g/person/day for meat, kidney and liver, respectively. Median dietary exposures to total mercury from caribou tissues were estimated to be 0.138 γg/kg body weight for women of child-bearing age and 0.223 γg/kg body weight for other adults. Caribou tissues were found to contribute high levels of important nutrients to the diet and pose minimal health risk from mercury exposure. © 2011 Elsevier Inc.

Muller C.E.,Empa - Swiss Federal Laboratories for Materials Science and Technology | Muller C.E.,ETH Zurich | De Silva A.O.,Environment Canada | Small J.,Environment Canada | And 6 more authors.
Environmental Science and Technology | Year: 2011

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 (0.02-0.26 ng/g wet weight (ww) sum (Σ) PFCAs and 0.002-0.038 ng/g ww PFOS). Wolf liver showed highest concentrations (10-18 ng/g ww ΣPFCAs and 1.4-1.7 ng/g ww PFOS) followed by caribou liver (6-10 ng/g ww ΣPFCAs and 0.7-2.2 ng/g ww PFOS). Biomagnification factors were highly tissue and substance specific. Therefore, individual whole body concentrations were calculated and used for biomagnification and trophic magnification assessment. Trophic magnification factors (TMF) were highest for PFCAs with nine to eleven carbons (TMF = 2.2-2.9) as well as PFOS (TMF = 2.3-2.6) and all but perfluorooctanoate were significantly biomagnified. The relationship of PFCA and PFSA TMFs with the chain length in the terrestrial food chain was similar to previous studies for Arctic marine mammal food web, but the absolute values of TMFs were around two times lower for this study than in the marine environment. This study demonstrates that challenges remain for applying the TMF approach to studies of biomagnification of PFCAs and PFSAs, especially for terrestrial animals. © 2011 American Chemical Society.

Riget F.,University of Aarhus | Braune B.,Carleton University | Bignert A.,Swedish Museum of Natural History | Wilson S.,Arctic Monitoring and Assessment Programme AMAP Secretariat | And 17 more authors.
Science of the Total Environment | Year: 2011

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. No generally consistent trend was evident across tissues and species from the circumpolar Arctic during the last 30. years or so. However, there was a clear west-to-east gradient in the occurrence of recent increasing Hg trends, with larger numbers and a higher proportion of biotic datasets in the Canadian and Greenland region of the Arctic showing significant increases than in the North Atlantic Arctic. Most of the increasing datasets were for marine species, especially marine mammals. A total of 16 (19%) out of the 83 time-series could be classified as "adequate", where adequate is defined as the number of actual monitoring years in a time-series being equal to or greater than the number of years of sampling required to detect a 5% annual change in Hg concentrations, with a significance level of P < 0.05 and 80% statistical power. At the time of the previous AMAP Assessment, only 10% of the Hg time-series were deemed adequate. If an additional 5. years of data were to be added to the current set of time-series, it is predicted that 53% of time-series would become adequate. © 2011 Elsevier B.V.

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