Concentrations of polychlorinated dibenzodioxins and dibenzofurans (pg/g wet wt) in Yukon snowshoe hare and spruce grouse liver tissue. Each column is the ...
Contaminants in Yukon Country Foods
Mary Gamberg Gamberg Consulting Box 10460 Whitehorse, Yukon Y1A 7A1
June, 2000
Prepared for Yukon Contaminants Committee and Department of Indian and Northern Affairs Northern Contaminants Program Whitehorse, Yukon
Table of Contents 1. Executive Summary ............................................................................................................................................. 1 2. Introduction .......................................................................................................................................................... 4 3. Methods ................................................................................................................................................................ 4 3.1 Sampling......................................................................................................................................................... 4 3.2 Contaminant analysis..................................................................................................................................... 7 3.3 Statistical Analysis......................................................................................................................................... 8 4. Results and Discussion ........................................................................................................................................ 8 4.1 Organic contaminants .................................................................................................................................... 8 4.1.1 Large Mammals...................................................................................................................................... 8 4.1.2 Small Mammals...................................................................................................................................... 11 4.1.3 Birds ........................................................................................................................................................ 12 4.1.4 Haines Junction pipeline area ................................................................................................................ 13 4.1.5 Summary ................................................................................................................................................. 13 4.2 Inorganic elements......................................................................................................................................... 13 4.2.1 Arsenic .................................................................................................................................................... 14 4.2.2 Cadmium ................................................................................................................................................. 20 4.2.2.1 Mammals ......................................................................................................................................... 21 4.2.2.2 Birds ................................................................................................................................................. 25 4.2.2.3 Vegetation........................................................................................................................................ 26 4.2.2.4 Health Effects .................................................................................................................................. 27 4.2.3 Copper ..................................................................................................................................................... 27 4.2.4 Lead ......................................................................................................................................................... 29 4.2.5 Mercury ................................................................................................................................................... 30 4.2.6 Zinc.......................................................................................................................................................... 32 4.2.7 Summary ................................................................................................................................................. 35 5. Appendices ........................................................................................................................................................... 38
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List of Tables Table 1. Number of samples collected for the Yukon country Foods Study. ...................................................... 5 Table 2. Number of vegetation samples collected for the Yukon Country Foods Study. ................................... 6 Table 3. Organochlorine concentrations in tissues of Yukon mammals (ng/g wet wt)....................................... 8 Table 4. Concentrations of polychlorinated dibenzodioxins and dibenzofurans (pg/g wet wt) in Yukon flora and fauna. ......................................................................................................................... 10 Table 5. Organochlorine concentrations in Yukon birds and vegetation (ng/g wet wt). All vegetation samples are from the pipeline area of Haines Junction............................................................... 11 Table 6. Element concentrations in kidneys of Yukon wildlife (mg/kg dry wt).................................................. 15 Table 7. Element concentrations in livers of Yukon wildlife (mg/kg dry wt). NM= not measured........................................................................................................................................................... 16 Table 8. Element concentrations in muscle of Yukon wildlife (mg/kg dry wt). NM= not measured........................................................................................................................................................... 17 Table 9. Element concentrations in bone of Yukon wildlife (mg/kg dry wt). ..................................................... 18 Table 10. Element concentrations in miscellaneous matrices in Yukon wildlife (mg/kg dry wt). ............................................................................................................................................................. 19 Table 11. Element concentrations in Yukon vegetation (mg/kg dry wt).............................................................. 19
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List of Figures Figure 1. Liver and kidney arsenic concentrations in mammals collected from Watson Lake. Note: As levels in red squirrel liver and beaver kidneys were below detection limits of 1.58 and 2.21 mg/kg respectively. ................................................................................................... 20 Figure 2. Kidney cadmium concentrations in Yukon large mammals.................................................................. 21 Figure 3. Liver cadmium in Porcupine caribou...................................................................................................... 22 Figure 4. Liver cadmium concentrations in caribou and moose from Dawson City, Yukon. .............................................................................................................................................................. 22 Figure 5. Cadmium concentrations in wildlife liver and kidney from two Yukon locations............................................................................................................................................................ 23 Figure 6. Kidney cadmium concentrations in moose from Ontario and the Yukon. ........................................... 24 Figure 7. Cadmium concentrations in wildlife liver and kidney. All values are mg/kg wet wt except for mink kidney and liver which are mg/kg dry wt. ..................................................................... 24 Figure 8. Cadmium concentrations in ruffed grouse kidneys from five Yukon communities. .................................................................................................................................................... 25 Figure 9. Cadmium concentrations in twigs from two sites in the Yukon. .......................................................... 26 Figure 10. Liver copper concentrations in mammals and birds from two Yukon communities. .................................................................................................................................................... 28 Figure 11. Copper concentrations in tissues from mink and beaver..................................................................... 28 Figure 12. Mercury concentrations in mink kidney and caribou liver from four sites in Canada. Mink kidney values are expressed as wet weight; caribou liver values are expressed as dry weight................................................................................................................................... 32 Figure 13. Mercury concentrations in kidney and liver of Yukon wildlife.......................................................... 33 Figure 14. Kidney zinc concentrations in mammals collected from Watson Lake, Yukon. ............................... 34
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List of Appendices A-1. Organochlorine concentrations (ng/g wet wt) in liver tissue of Yukon wildlife. Each column is the result of one pooled sample of N individuals. ............................................................................................... 40 A-2. Organochlorine concentrations (ng/g wet wt) in liver tissue from snowshoe hare and spruce grouse collected from the pipeline and control areas in Haines Junction, Yukon in 1995. Each column is the result of one pooled sample of N individuals. ............................................................................................... 43 A-3. Concentrations of polychlorinated dibenzodioxins and dibenzofurans (pg/g wet wt) in Yukon snowshoe hare and spruce grouse liver tissue. Each column is the result of one pooled sample of N individuals. ....................................................................................................................................................... 44 A-4. Organochlorine concentrations (ng/g wet wt) in fat tissue of Yukon mammals. Each column is the result of one pooled sample of N individuals. ............................................................................................... 45 A-5. Concentrations of polychlorinated dibenzodioxins and dibenzofurans (pg/g wet wt) in fat tissue from Yukon mammals. Each column is the result of one pooled sample of N individuals................................ 47 A-6. Organochlorine concentrations (ng/g wet wt) in muscle tissue of Yukon waterfowl collected in Whitehorse in 1988. Each column is the result of one pooled sample of N individuals............................ 50 A-7. Organochlorine concentrations (ng/g wet wt) in vegetation collected from the pipeline area of Haines Junction, Yukon in 1995. Each column is the result of one pooled sample of N individuals. .................. 51 A-8. Concentrations of polychlorinated dibenzodioxins and dibenzofurans (pg/g wet wt) in vegetation collected from the pipeline area of Haines Junction, Yukon in 1995. Each column is the result of one pooled sample of N individual samples). ....................................................................................................... 52 A-9. Element concentrations in Yukon large mammal kidneys (mg/kg dry wt). ................................................ 53 A-10. Element concentrations in Yukon small mammal kidneys (mg/kg dry wt). ............................................. 56 A-11. Element concentrations in Yukon bird kidneys (mg/kg dry wt). ............................................................... 61 A-12. Element concentrations in Yukon large mammal liver (mg/kg dry wt)..................................................... 65 A-13. Element concentrations in Yukon small mammal liver (mg/kg dry wt).................................................... 69 A-14. Element concentrations in Yukon bird liver (mg/kg dry wt)...................................................................... 74 A-15. Element concentrations in Yukon large mammal muscle (mg/kg dry wt). ............................................... 78 A-16. Element concentrations in Yukon small mammal muscle (mg/kg dry wt)................................................ 80 A-17. Element concentrations in Yukon bird muscle (mg/kg dry wt).................................................................. 84 A-18. Element concentrations in Yukon large mammal bone (mg/kg wet wt except calcium which is expressed as % wet wt).................................................................................................................................... 85 A-19. Element concentrations in Yukon small mammal bone (mg/kg wet wt except calcium which is reported as % wet wt). ..................................................................................................................................... 86
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List of Appendices (cont’d) A-20. Element concentrations in miscellaneous matrices from Yukon wildlife (mg/kg dry wt). .................................................................................................................................................................... 88 A-21. Element concentrations in Yukon vegetation (mg/kg dry wt).................................................................... 91 A-22. Element concentrations in twigs from Simpson and Lootz Lakes in the Yukon (mg/kg dry wt). ................................................................................................................................................ 95 A-23. Health Advisory for Yukon wildlife from Health and Social Services, Yukon Territorial Government.................................................................................................................................... 96
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Executive Summary Environmental contamination of food sources is an issue of major concern across Canada, and is being closely monitored in many areas, particularly in the north where country foods constitute a large portion of the diets of First Nations people. High levels of cadmium found in the livers and kidneys of arctic caribou have caused concern among Yukon First Nations and others using caribou as a food source, and raised the issue of contaminants in other food sources. This project was designed to work with individual First Nations to address specific concerns about contaminants in country foods in the Yukon. This study encompassed the Yukon communities of Watson Lake, Ross River and Teslin, Dawson and Haines Junction and enlisted the cooperation of local First Nations and outfitters. Community coordinators were designated in each First Nation, and requested to provide samples of country foods normally harvested for consumption. Outfitters, and subsequently, all Yukon hunters, were asked to provide tissue samples from moose and caribou. Other samples included in this study were obtained from a Yukon Territorial Government waterfowl study, a Canadian Wildlife Service waterfowl study, Yukon trappers and carcasses found by various Yukon biologists. Vegetation, kidney, liver, muscle and bone and other miscellaneous matrices were analyzed for 26 elements. Fat and liver tissues were analyzed for a variety of organic contaminants. Although it was the intent in this project, to explore differences in contaminant levels among species and geographical areas in the Yukon, as well as relationships between age of the animal and element concentrations, statistical analysis of the data was difficult because animals and plants were sampled opportunistically and not according to a balanced experimental design. In addition, age was only able to be determined to year in three species. No statistics were able to be performed on organic data because most samples were analyzed as pools (due to financial restrictions), so sample sizes were inadequate for valid comparisons. Therefore, only selected statistical comparisons of inorganic data were performed.
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The effect of age on metal concentration was tested using liver and kidney data (separately) from moose, caribou (Porcupine herd only) and beaver - the only three species to be aged to year. A linear regression was used when the data was normal and was not heteroscedastic, otherwise a Spearman’s Rank Correlation was used. The effects of species and location on element concentrations were tested using liver and kidney data (separately). A t-test or one-way ANOVA was used if the data were normal, or a Mann-Whitney Rank Sum Test or Kruskal-Wallis One Way ANOVA was used if they were not. Where appropriate, a general linear model was used to include the effect of age in the model. Most organic contaminant concentrations were low in Yukon fauna and flora when compared to similar species from other parts of Canada. Most of these low-level contaminants were probably carried to the Yukon via large air masses (long-range transport), and are typical of arctic ecosystems. Carnivores, in general, tended to have higher concentrations of many organic contaminants than herbivorous animals. Although it is difficult to draw conclusions with such low sample sizes, this may be a case of biomagnification. In the few cases where higher concentrations of some compounds were found, it was a result of a very small number of animals, suggesting point sources of contamination (possibly dumps). There was no evidence that wildlife and vegetation from around the Haines Junction pipeline area were more contaminated than other areas near the town of Haines Junction, or other parts of the Yukon. Yukon wildlife does not appear to be at risk from organic contaminants. Although the Yukon territory is a mineral-rich area, few of those minerals pose a risk to its wildlife. Copper and zinc are trace elements required by all animals in small amounts, and there is no evidence that they are present at elevated levels in Yukon wildlife. Arsenic and lead are toxic elements that are not required for life, but are present at low levels in most wildlife species. Although several individual animals from the Yukon had high levels of lead in various tissues, this is suggestive of contamination by lead shot or bullets, or exposure to a point source of lead (either birds consuming lead shot as grit, or a point source such as a dump). There is no evidence of broad-scale contamination of the Yukon environment by arsenic or lead, or of significant point sources of these contaminants affecting Yukon wildlife. Mercury, also a toxic element, was higher in caribou than in other Yukon wildlife studied. The source of this mercury is likely from long-range transport of atmospheric mercury being absorbed by lichens, a major food source for caribou. Other species also had measurable levels of mercury, at concentrations comparable to or lower than the same species from other parts of Canada. The ratio of renal to hepatic mercury seen in resident Yukon wildlife suggests that most of the mercury is in the less toxic inorganic form, as opposed to the more bioavailable and more toxic methylmercury. Cadmium is a toxic element that, like the others discussed, occurs naturally in the Yukon, sometimes in high concentrations. Certain plants, such as willows, absorb naturally occurring cadmium from the ground and pass it on to any herbivore that browses the plant. This results in some Yukon wildlife (moose, beaver, grouse and ptarmigan) having higher concentrations of cadmium than similar species from other parts of Canada. In addition to this local source of cadmium, long-range atmospheric transport deposits cadmium broad-scale over the arctic where it is absorbed by lichens and then is passed on to caribou feeding on the lichens. This results in most Yukon caribou having cadmium concentrations similar to other arctic caribou. Those caribou living in cadmium-rich areas of the Yukon and browsing on high-cadmium willows may have even higher levels. Once ingested, cadmium is stored in the kidney and liver of the animal, but not in the muscle tissue. Health Canada has advised limiting consumption of liver and kidney of some Yukon wildlife (moose and caribou in particular), but has put no limit on the consumption of muscle from any species. Cadmium was positively correlated with age in the only species able to be aged to year (beaver, moose and caribou). This accumulation of cadmium over time has been well-documented in the literature, and suggests that older animals would be expected to have higher cadmium concentrations than younger animals of the same species. Geographical location did not significantly affect the concentration of any of the elements examined. While species did not have a significant effect on lead or mercury concentrations, it did have an effect on arsenic, cadmium, copper and zinc levels. In the case of cadmium, this can be attributed to dietary differences, herbivores that consume cadmium-accumulating plants (such as beaver and moose consuming willows), having higher cadmium concentrations than those herbivores that prefer
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plants that do not tend to accumulate so much cadmium (such as caribou consuming lichens). The case is not so clear-cut for the other elements, but may reflect differences in dietary habits or in physiology. However, since concentrations for each of the elements fall within ranges considered ‘normal’ for domestic animals, the significance of the differences seen among species is largely academic. The elements measured in this project appear to be present in Yukon flora and fauna at baseline levels and there is no evidence of element concentrations that would be considered elevated. Even cadmium, which is present at high levels in some Yukon wildlife, likely comes from natural sources and should be considered ‘baseline’ for this area. Yukon wildlife does not appear to be at risk from inorganic contaminants.
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Introduction Environmental contamination of food sources is an issue of major concern across Canada, and is being closely monitored in many areas, particularly in the north where country foods constitute a large portion of the diets of First Nations people. High levels of cadmium found in the livers and kidneys of arctic caribou (Gamberg and Scheuhammer 1994, Gamberg 1993, Crete et al. 1989, Froslie et al. 1986) have caused concern among Yukon First Nations and others using caribou as a food source, and raised the issue of contaminants in other food sources. In 1993 three caribou herds were studied to determine the extent of the high cadmium levels in caribou and to try to ascertain its source (Gamberg and Mychasiw 1994). In 1994 a project was initiated to determine levels of contamination in country foods in the Yukon. This project was designed to work with individual First Nations to address specific concerns about contaminants in country foods in the Yukon.
Methods Sampling A pilot study was carried out in 1994/95 to assess the feasibility of a larger contaminants program. The pilot study encompassed the Yukon communities of Watson Lake, Ross River and Teslin, and enlisted the cooperation of local First Nations and outfitters. Community coordinators were designated in each First Nation, and requested to provide samples of mammals normally harvested for consumption. In most cases, the entire animal was provided, the required tissues removed in the laboratory, and the remainder of the carcass returned to the hunter or trapper, or donated to one of the First Nations. When samples of large mammals were provided, each tissue (kidney, liver, bone and muscle) was stored separately in a clean plastic bag, and where appropriate, a tooth was taken for aging purposes. Outfitters were given sampling kits and asked to store kidney, liver, bone and muscle samples in Whirl-pak bags, and fat samples in hexane and acetone-rinsed tinfoil, and then in Whirl-paks. Surgical gloves and solvent-rinsed scalpels were provided for this purpose. All samples were frozen at -20°C until processed. Community coordinators and outfitters were paid a fee for each sample provided. As further funding became available, the communities of Dawson and Haines Junction were added to the pilot project, but at a relatively late date. No samples were submitted from Haines Junction, and only four from Dawson. In 1994/95 the contaminants program was expanded to encompass the entire territory, and include all mammals, birds, fish and plants that were harvested for consumption or medicinal uses. A sampling list was devised with each First Nation to ensure that the research would be locally relevant, and community coordinators were designated in each community as before. Each First Nation was encouraged to specify areas of special concern for more intensive sampling, although Champagne Aishihik (Haines Junction area) was the only one to do so. Their concern was pesticide use around an old pipeline in their traditional area, so vegetation samples and small mammals were collected from the area and tagged for organic contaminant analyses. Several fish were submitted from other First Nations for analysis, and were contributed to the existing fish contaminants program being conducted by DIAND to ensure comparability of data (contact: Mark Palmer, DIAND, Whitehorse). Fish will, therefore, not be considered in this report. Samples were collected from mammals as previously described, and because birds were submitted as whole carcasses, they were treated in the same way as small mammals. Vegetation samples were collected into clean plastic bags and frozen for storage. Sampling for this portion of the project began in December 1994 and continued for a full calendar year until the end of November 1995 so that samples could be taken during the traditional time of harvest. Additional vegetation (browse) samples were taken in the winter of 1995 to determine the element composition of moose and caribou winter forage. Samples obtained are listed in Tables 1 and 2.
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Table 1. Number of samples collected for the Yukon Country Foods Study.
Common Name Species First Nations YTG Outfitters Large Mammals 1993-95 1991-95 1993/94 Black bear Ursus americanus 1 0 0 Caribou Rangifer tarandus 6 70 4 Dall sheep Ovis dalli 0 0 5 Elk Cervus elaphus 0 1 0 Moose Alces alces 5 9 6 Mountain goat Oreamnos americanus 0 0 4 Mule Deer Odocoileus hemionus 0 1 0 Small Mammals Trappers (1993) Arctic Ground Squirrel Citellus parryi 20 0 0 Beaver Castor canadensis 15 0 0 Hoary marmot Marmota caligata 0 3 0 Lynx Lynx canadensis 1 1 0 Mink Mustela vison 0 0 3 Muskrat Ondatra zibethicus 13 0 0 Pine marten Martes americana 0 0 7 Porcupine Erethizon dorsatum 6 0 0 Red fox Vulpes vulpes 0 0 1 Red Squirrel Tamiasciurus hudsonicus 27 0 0 Short-tailed weasel Mustela erminea 0 0 8 Snowshoe hare Lepus americanus 28 0 0 * Birds YTG (1988) CWS (1994)+ American wigeon Anas americana 0 4 0 Green-winged teal Anas crecca 0 17 0 Grouse, Blue Dendraguapus obscurus 2 0 1 Grouse, Ruffed Bonasa umbellus 4 0 3 Grouse, Spruce Dendragapus canadensis 15 0 24 Mallard Anas platyrhynchos 2 10 0 Northern pintail Anas acuta 0 3 0 Ptarmigan Lagopus sp. 0 0 6 Ptarmigan, Rock Lagopus mutus 0 0 4 Ptarmigan, White-tailed Lagopus leucurus 0 0 2 Ptarmigan, Willow Lagopus lagopus 1 0 8 Scaup Aythya sp. 1 0 0 * Yukon Territorial Government waterfowl project (Renewable Resources, YTG, Whitehorse, Yukon) + Canadian Wildlife Service waterfowl project (National Wildlife Research Centre, Hull, Quebec)
Hunters 1994-95 1 22 0 0 47 0 0
Total 2 102 5 1 67 4 1 20 15 3 2 3 13 7 6 1 27 8 28 4 17 3 7 39 12 3 6 4 2 9 1
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Table 2. Number of vegetation samples collected for the Yukon Country Foods Study.
Common name Aspen Balsam Poplar Bearberry Birch Black Currant Blueberry Cranberry, Highbush Cranberry, Lowbush Crowberry Dandelion Dogwood Fireweed Gooseberry Juniper Larch Lodgepole Pine Mushroom Mushroom Poplar Raspberry Rhubarb Rose Sage Saskatoon Silverberry Soapberry Spruce Strawberry Wild Onion Willow Yarrow
Species Populus tremuloides Populus balsamifera Arctostaphylos uva-ursi Betula papyrifera Ribes hundonianium Vaccinium uliginosum Viburnum edule Vaccinium vitis-ideae Empetrum nigrum Taraxacum officinale Cornus stolonifera Epilobium angustifolium Ribes oxyacanthoides Juniperus communis Larix laricina Pinus contorta Boletus sp. Agaricus sp. Populus sp. Rubus ideaus Polygonum alaskanum Rosa acicularis Artemisia frigida Amelanchier alnifolia Elaeagnus commutata Sheperdia canadensis Picea mariana Fragaria virginiana Allium schoinopraum Salix sp. Achillea millefolium
N 6 2 1 5 2 5 9 5 8 2 2 5 1 2 1 1 1 1 1 3 3 9 3 2 1 5 2 1 3 12 3
Although several outfitters collected samples for the project in 1993, the total number of samples from large mammals was very small. As a result, the collection strategy for these animals was changed in the fall of 1994 to a request to all Yukon hunters to submit samples from moose and caribou. The request for kidney, liver, muscle and a tooth was advertised through the territorial hunter synopsis, posters, radio and newspaper, and a travel mug was given to each hunter who submitted a sample. The response was quite good. Each hunter who had submitted a sample was subsequently sent a letter telling them the age of their moose or caribou, and giving them general information about the project and the results. Hunter collections were not planned for the fall of 1995 because of financial restrictions, but because the request was inadvertently left in the territorial hunter synopsis, any samples submitted were accepted. Samples from 15 animals were submitted that year as compared with 63 the previous year. Letters were again sent to each hunter with ages and information. Other samples included in this study were obtained from a Yukon Territorial Government waterfowl study in 1988, a Canadian Wildlife Service waterfowl study in 1994, Yukon trappers and carcasses found by various Yukon biologists (N=4).
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Contaminant analysis All carcasses and samples were stored at -20oC until processed. Thereafter, samples destined for inorganic analysis were stored at -20oC and those for organic analysis were stored at -80 oC. Whole carcasses were dissected in the laboratory under clean conditions. Depending on the species, age was determined from pelage characteristics, epiphyseal closure or a tooth. Teeth were aged by Matson’s Laboratory (Montana) using the cementum annuli technique. Subcutaneous or kidney fat was extracted and stored in chemically cleaned glass jars with teflon-lined lids for organic analysis. If not enough fat was present for analysis, liver was used. These samples were taken from all 1993/94 mammals, but in subsequent years, only if there was a particular concern. Bone samples (the humerus from small mammals; a piece of the metatarsal from large mammals) were taken from 1993/94 mammals only, stored in plastic bags, and analyzed for inorganic contaminants. Muscle, liver and kidney were taken from all animals whenever possible, stored in plastic bags and analyzed for inorganic contaminants. Muscle was normally taken from the gastrocnemius muscle, except in the case of the samples obtained from the Yukon Territorial Government and Canadian Wildlife Service waterfowl projects. All muscle samples from these projects were from the pectoralis. Depending on the size of the organ, all or a portion of the liver was extracted, and one or both entire kidneys were used. Samples from large mammals submitted from First Nations, outfitters and hunters were all treated the same way. All fat was removed from each kidney, and the membranous kidney capsule was removed. If the kidney was submitted with the capsule already removed, it was rinsed with distilled water to remove external contamination. A thin outer layer was removed from each side of the pieces of liver and muscle samples for the same reason. Fat tissue, only requested from outfitters, was analyzed as submitted. All animal tissue and vegetation samples were homogenized before being analyzed to ensure homogeneity. All organic analyses were conducted by Axys Analytical Services Ltd., Sidney, BC. Depending on the collection, species and the specific concern, samples were analyzed for some or all of the following: a suite of organochlorines (hexachlorobenzene, α-, β-, γ- HCH, heptachlor, heptachlor epoxide, oxychlordane, cisand trans- chlordane, cis- and trans-nonachlor, o,p’-and p,p’-DDE, DDD and DDT, mirex, aldrin, αendosulphan, dieldrin, endrin and methoxychlor), PCBs as Arochlors (all by high resolution gas chromatography with low resolution mass spectrometric detection [HRGC/LRMS]), toxaphene (by electron capture negative ion gas chromatography with mass spectrometric detection [GC/MS]) and polychlorinated dibenzodioxins/dibenzofurans (by high resolution gas chromatography with high resolution mass spectrometric detection [HRGC/HRMS]). The most polar pesticides were analyzed by gas chromatography with an electron capture detector (GC/ECD). All results of organic analyses are presented on a wet weight basis. Collections from the pilot project in 1993/94 were analyzed for a suite of 22 inorganic contaminants (aluminum, antimony, arsenic, barium, beryllium, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, mercury, molybdenum, nickel, selenium, strontium, thallium, vanadium and zinc) by ASL, Vancouver, BC, using the inductively coupled plasma technique (ICP). Subsequent collections were analyzed for a series of 26 inorganic contaminants (the previous 22 as well as boron, silver, tin and uranium) by Elemental Research Inc., Vancouver, BC, using ICP with mass spectroscopy (ICP-MS). All results of inorganic analyses are presented on a dry weight basis except as noted. Standard quality controls and quality assurances were practiced by all laboratories and approved by the Arctic Environmental Strategy quality control supervisor. In addition, certified blind samples developed for this project by the National Research Council were submitted for analysis with each batch of samples to ensure quality of the data. Additional blind samples provided by Environment Canada (Vancouver) were analyzed with samples from the 1994-96 collections. The quality of these data were examined and approved by the quality control supervisor from Environment Canada.
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Statistical Analysis It was the intent, in this project, to explore differences in contaminant levels among species and geographical areas in the Yukon, as well as relationships between age of the animal and element concentrations. However, statistical analysis of the data was difficult because animals and plants were sampled opportunistically and not according to a balanced experimental design. As a result, some species were not sampled in some areas, and sample sizes were extremely variable. In addition, age was only able to be determined to year in three species (moose, caribou and beaver). No statistics were able to be performed on organic data because most samples were analyzed as pools (due to financial restrictions), so sample sizes were inadequate for valid comparisons. Finally, some element concentrations measured were below the detection limit of the analytical technique. In most of these cases, ½ the detection limit was used in calculations, but when levels of a particular element were below the detection limit in all samples from one species or one location, the variability within that group was functionally zero. This would artificially increase the chances of finding significant differences among species or locations, even if none were present. Because of these difficulties, only selected comparisons of inorganic data were performed. These are described for each element discussed. The effect of age on metal concentration was tested using liver and kidney data (separately) from moose, caribou (Porcupine herd only) and beaver, the only three species to be aged to year. A linear regression was used when the data was normal and was not heteroscedastic, otherwise a Spearman’s Rank Correlation was used. Differences among species were tested when 10 or more samples were taken from more than one species from a particular area. Similarly, differences among areas were tested when 10 or more samples were taken from more than one area from a particular species. A t-test or one-way ANOVA was used if the data were normally distributed, or a Mann-Whitney Rank Sum Test or Kruskal-Wallis One Way ANOVA was used if they were not. Age was unable to be included in most of these tests as a factor because of the low number of species for which it was available. However, where appropriate, a general linear model (GLM) was used to test the effect of location, age and species. Tests were performed only if more than ½ the measurements for an element from one species or location were above the detection limit for that element. Data for kidney and liver were analyzed separately. Metals in bone, muscle and other matrices were not analyzed statistically because of insufficient sample sizes. Because of the difficulty in analyzing the data using one model to include all three effects, α was assumed at 0.017 (or 0.05/3) to maintain a 95% confidence level. In bar charts presented as figures, different letters over the bars indicate a statistically significant difference between or among the bars.
Results and Discussion Organic contaminants Summaries of organic contaminants in Yukon flora and fauna are presented in Tables 3-5 in which data are grouped by contaminant type, species and location. Raw data are presented in appendices 1-8. Large Mammals The predominant organochlorines (OCs) found in fat tissue of caribou, Dall sheep, moose and mountain goats were hexachlorobenzene (HCB) and hexachlorocyclohexanes (HCH). Levels of both of these OCs were lowest in sheep and highest in the Wolf Lake caribou (Table 3). These more volatile and less persistent compounds have been shown to be the predominant OCs in arctic air (Patton et al. 1989), and in other terrestrial herbivores in the Canadian North (Muir et al. 1997, Thomas et al. 1992, Salisbury et al. 1992). Concentrations of these compounds found in Yukon large mammals are generally lower than found in caribou from the NWT, where HCB ranged from 20 -129 ng/g (lipid corrected) in caribou fat, and total HCH ranged from 3.3 ng/g to 40 ng/g in the same tissue (Muir et al. 1997). Table 3. Organochlorine concentrations in tissues of Yukon mammals (ng/g wet wt).
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Common name Herd/Area Large Mammals Caribou Wolf Lake Nahanni Dall Sheep Ross River Watson Lake Moose Ross River Mountain Goat Watson Lake Small Mammals Arctic Ground Kluane Squirrel Ross River Selkirk Whitehorse Beaver Ross River Teslin Watson Lake Lynx Haines Junction Mink Watson Lake Muskrat Ross River Watson Lake
Pine Marten Porcupine
Red Fox Red Squirrel Snowshoe Hare
Whitehorse Watson Lake Ross River Watson Lake Watson Lake Whitehorse Haines Junction (pipeline) Ross River Watson Lake Whitehorse
N1
Tissue
HCB2 !HCHs3 !CHL4 !DDT5 Dieldrin Tox6 !PCBs7
1 2 1 2 1 4
Fat Fat Fat Fat Fat Fat
18 15 7 6.5 3.2 7.3
9.8 5 2.7 1.3 2.4 2
