The Institute of Social and Economic Research
University of Alaska Anchorage

In collaboration with the

Alaska Native Science Commission

June, 1999

The principal goal of the Traditional Knowledge and Radionuclides project is to build capacity among Alaska Natives to identify and address their concerns about radionuclides, other types of contamination, as well changes in the environment and people’s health. The most important components of capacity to take effective action are ownership and trust. We mean by ownership that Alaska Natives are able to take responsibility for their own lives. We mean by trust that Alaska Natives are able to trust the world in which they live - the natural environment, the efficacy of their own actions, and the actions of others.

The purpose of this report is to summarize research-based knowledge on environmental changes experienced by Alaska Natives. We plan to have researchers review this summary at the Arctic Science Conference in September 1999. We then plan to bring a revised version of this summary to Alaska Natives in a series of regional meetings starting in the fall of 1999. We will ask Native participants to comment on the research-based summary in the context of their related traditional knowledge. We will then develop a comparative summary of the research-based and traditional knowledge-based perspectives. We will convene a meeting of researchers and Natives in the fall of 2000. The purpose of this meeting will be to develop a common agenda and to better understand the differences between the research and traditional knowledge-based perspectives.

The project uses a community-based model rather than a research-based model. The research-based model begins with a recognition of potential sources of contaminants and specific pathways by which these contaminants move through the food chain, air, and water. Funding for our study came from concerns about radionuclide contamination of Native foods.

The community-based model begins with local observations of environmental and human health changes. This year we’ve been holding regional meetings with Alaska Natives to understand their concerns. Note that while funding for the project came as the result of concerns about radionuclides, with the approval of our funding agency - the Environmental Protection Agency (EPA) - we are starting with the broad question about concerns about environmental changes of any kind, from any source.

Alaska Natives have told us about things that they directly observe that are of concern. These environmental changes include signs of increased disease and abnormalities in wildlife. They also see increased numbers of people with cancers. In our regional meetings, Alaska Natives have said that they want to understand the causes of these observed changes and to take action to restore the health of the natural environment.

We therefore want to bring research-based knowledge to Alaska Natives who can use it in the context of Native traditional knowledge. We are social science researchers and are not qualified to develop a summary of natural science research from scratch. We can, however, compile a summary based on existing summaries of relevant research.

• Preface
• Executive Summary
• Introduction
• The Arctic
• Physical Pathways
• Polar Ecology
• Peoples of the North
• Persistent Organic Pollutants
• Heavy Metals
• Radioactivity
• Acidification and Arctic Haze
• Petroleum Hydrocarbons
• Climate Change
• Pollution and Human Health

This document contains hot-links directly to the AMAP web site to access these chapters (see blue underlined text).

Although the U.S. was one of the countries planning AMAP, the U.S. did not contribute much research knowledge to the AMAP report. The U.S. has also not conducted a coordinated research effort on contaminants like other AMAP countries. We decided that the best way to overcome this knowledge gap in the AMAP report was to convene a group of U.S. researchers to share their knowledge. We looked for summary materials pertaining to the Arctic that could help structure their discussion.

At the time (April 1997), the AMAP report was not yet available. Researchers from the Canadian Northern Contaminants Program allowed us to use a chapter from an early summary of their major conclusions as a basis for building a summary on the status of knowledge in Alaska. Canada’s Department of Indian Affairs and Northern Development (DIAND) published this summary as, "Highlights of the Canadian Arctic Contaminants Assessment Report: A Community Reference Manual" (DIAND 1997a). DIAND published a larger companion technical report in 1997 titled, "Canadian Arctic Contaminants Assessment Report" (DIAND 1997b).

We convened 15 researchers to assess the applicability to Alaska of the major conclusions of the Canadian Northern Contaminants Program. The Canadian program’s conclusions are based on over 20 million dollars of research over six years. The program is an invaluable source of information relevant to Alaska. We published findings of our workshop as, "Results of a Workshop on Uptake and Effects of Contaminants in Native Foods" (ISER 1999).

The Canadian and AMAP reports differ somewhat in scope from each other and from what probably would have been addressed from a U.S. perspective. Thus our approach of starting with the Canadian conclusions does not provide a comprehensive summary addressing all U.S. concerns. We have therefore expanded our workshop summary in this summary of research-based knowledge.

We based our choice of what to add to the workshop summary on the concerns we are hearing from Alaska Native participants in our regional meetings. Their concerns stem from their own observations of decreased wildlife populations, animals and fish with abnormalities, and diseases among Native peoples. For example, Eric Iyapana from Little Diomede Island said,

Northwest Arctic Regional Meeting, 1998

Both AMAP and the Canadian Northern Contaminants Program focused on persistent organic pollutants, heavy metals, and radionuclides. The broader geographic focus of AMAP led researchers to also consider radionuclide and heavy metal contaminants from northwestern Russia. AMAP also paid some attention to climate change, petroleum hydrocarbons, and Arctic haze. Climate change is currently a main focus of AMAP.

A summary of research knowledge based on a U.S. (Alaska) perspective would probably devote more attention to concerns about radionuclide contamination from Russia. There are also concerns in Alaska about the effects of climate change on the ocean waters around Alaska and on drying of lakes and wetlands. Our workshop summary based on the Canadian research findings does not address these concerns.

The AMAP report has relevant information on Russian contaminants and on climate change. We add AMAP findings on these points to our workshop summary. We also add the main findings of several other reports:

We first direct the reader to each section of the AMAP summary, "Arctic Pollution Issues: A State of the Arctic Environment Report". To preserve the integrity of the findings presented in the original AMAP report, we do not attempt to develop our own summary of AMAP findings. We have reproduced the Summary section of each AMAP chapter in bullet form in this report to allow the reader to more readily compare the AMAP summary points with the summary points from our workshop and additional source material.

We follow the AMAP findings with relevant findings from our Results of a Workshop on Uptake and Effects of Contaminants in Native Foods. Where appropriate, we then add findings from the additional reports on radionuclide contamination and climate change.

As stated above, we do not want to inadvertently change the meaning of AMAP researchers by summarizing their summary. We think it is best for you to read the six page AMAP summary as a whole.

Based on a comparison of the AMAP summary and the Alaska workshop on Uptake and Effects of Contaminants in Native Foods in Alaska we conclude that all AMAP findings apply equally well to Alaska. We also note that one of the AMAP findings is:

• In winter, industrial areas of Eurasia are within the Arctic air mass, which provides for efficient air transport of particle-bound contaminants (e.g. radionuclides, sulfates) across the pole. Semi-volatile contaminants (e.g. persistent organic pollutants, mercury) are carried to the Arctic by cycles of evaporation, transport, and condensation in a multi-hop process. The cold climate traps them more effectively here than anywhere else on the globe.
• Snow, rime ice, rain, and dry deposition cleanse the air and contaminate the surfaces on which they land. The contaminants often end up in meltwater that feeds both rivers and the ocean surface layer.
• Rivers process contaminants along their routes by sedimentation and resuspension of particles. Lakes, estuaries and deltas serve as sediment traps and sinks for contaminants.
• Ice forming in the shelf seas can pick up contaminants from the coastal shelves, and can travel far in the Beaufort Gyre and Transpolar Drift. The ice may release its load of contaminants in the biologically productive shelf seas and in the North Atlantic, where they can be taken up into the food chain.
• Another important pathway is via the ocean currents. They act slowly compared with the atmosphere, but take water with water-soluble and particle-adsorbed contaminants from distant industrialized coasts into the Arctic within a few years, and out again through the East Greenland Current and the Canadian Archipelago. The sea is the final resting place for most contaminants.
• Modeling is a useful tool for understanding contaminant transport. Its importance will grow as the basic processes become better understood and the models improve.

• Low temperatures and extreme seasonal variations in light are some physical characteristics that limit the productivity of Arctic ecosystems and can make them more vulnerable to contaminants in the environment. In terrestrial ecosystems, lack of nutrients, waterlogged conditions on the tundra, and the lack of water in Arctic desert areas also limit productivity.
• The ability to gather and store energy is a prime concern for survival during the dark and cold winter. Therefore, fat plays a more important role in animal metabolism in the Arctic than in temperate regions. The importance of fat increases biomagnification [accumulation through predators eating prey] of fat-soluble contaminants. Bioaccumulation [uptake from air, water, soil and ingestion] of contaminants is also accentuated in many Arctic animals by long lives.
• Seasonal fluctuations are the norm in the Arctic, and many species migrate north to take advantage of the productive summer season. This includes large numbers of migratory birds that concentrate in wetland areas in the terrestrial environment and along the marginal ice zone in the marine environment.
• Terrestrial food webs in the Arctic are generally short, though long-lived lichens gather contaminants very efficiently and transfer these to grazing animals, such as caribou and reindeer. Freshwater food webs are also short, and predatory fish occur mostly in Low Arctic to subarctic ecosystems. Arctic marine food webs can be very complex but with only a few key species connecting the different levels.

To the above AMAP summary points, we add the following from the Alaska workshop on Uptake and Effects of Contaminants in Native Foods in Alaska:

• Alaska Natives have observed changes in the health of some animals and fish. They worry that these changes may be due to contaminants. We need to ask Native experts to share these observations in order to see patterns of change (11).

• Contaminants reach the Arctic through exposure of migrating species to non-local sources of contaminants (15).

• Local sites and the natural environment may be sources of contaminants (17).
• We need more data to understand the processes which move contaminants through the food chain. It is possible that accelerated processes during the spring may move contaminants through the food chain more quickly (18).

• The lives of indigenous and other Arctic peoples are closely linked to local resources that provide nourishing foods and spiritual connections to the environment.
• Food habits, living conditions, employment or subsistence activities, and access to health care are some of the characteristics in which Arctic populations differ from those farther south in the Arctic countries. Together, these factors complicate any assessment of the real and potential impact of contaminants to Arctic people. Specifically, experiences and results from lower latitudes cannot be directly transferred.
• Moreover, great differences between countries, between cultural groups, and between individuals within a community point to the importance of understanding local contexts when making assessments connected with contaminants and well-being.
• Communication is critical in the continued work in this area. Not only do Arctic residents have the right to good information about their environment and themselves, they also have knowledge that may assist our overall understanding of environmental damage.

To the above AMAP summary points, we add the following from the Alaska workshop on Uptake and Effects of Contaminants in Native Foods in Alaska:

• The diets of Alaska Natives are more likely to include predators which may concentrate contaminants (1). Alaska Native diets are also more likely to be higher in fats. These fats may contain higher concentrations of organochlorines.

• A substantial proportion, on the order of a third or more, of the meat and fish eaten by rural Alaska Natives comes from local harvests of fish and game. We do not have consumption data for most Alaska Native communities (10).
• The concept of "health" among Native people is holistic. Health is socially and culturally defined. It has spiritual dimensions. Alaska Natives have a strong traditional value of respect for the environment. They see degradation of the environment as a threat to health (227).
• Sharing of Native foods is a common practice in Alaska. Harvesting, sharing, processing, and consuming Native foods is an opportunity to practice and teach humility and spirituality (233).
• Imported sources of meat and fish are expensive and lower in protein, thiamin, riboflavin, niacin, and vitamin B12 than Native foods (257).
• If Alaska Natives were to stop eating Native foods, they would experience nutrition and protein deficiencies. Native foods are as important to Native social well-being as they are to physical health (231,255, 259).

• All persistent organic pollutants in AMAP’s monitoring program have been found in the Arctic. The levels are generally lower than in temperate areas, but for several substances they are still in concentration ranges in which effects on some animals are expected. These include reproductive effects in birds from DDT and in some marine mammals from PCBs and dioxin-like compounds. Current concentrations in several Arctic species are also close to or above thresholds known to be associated with immunosuppressive and neurotoxic effects. The most vulnerable animals are those high in the food web, such as polar bear and birds of prey.
• Biomagnification is one major factor contributing to the high levels and biological effects of persistent organic pollutants in Arctic animals. Another biological pathway is via migratory birds that overwinter in polluted environments.
• The major source of persistent organic pollutants in the Arctic is long-range transport via air currents, as demonstrated by monitoring of air concentrations. There may also be significant sources of some contaminants, such as PCBs, DDT, and hexachlorocyclohexane, within the AMAP region, but these are not well documented. Data from river water and sediments indicate that a substantial input from Russian rivers into the Arctic marine environment, but these data must still be verified.
• Available data point to some geographic trends. In general, the levels of PCBs and DDT seem to be higher around Svalbard, in the southern Barents Sea, and in eastern Greenland than in, for example, the Canadian High Arctic. Levels of hexachlorocyclohexane appear to be higher in the Canadian Arctic than in Eurasia. Very limited data from Russia and Alaska are available for this assessment. The lack of circumpolar data limits our understanding of sources, transport pathways, and mechanisms for focusing contaminants. The role of sea ice in transporting contaminants and then releasing them during melting warrants further investigation.
• A few studies of time trends point to a decreasing load of PCBs and DDT in subarctic regions from the 1970s to the 1980s, after use of these substances was restricted or banned. However, it is not clear whether this decline has continued from the 1980s to the 1990s, or if similar declines have occurred in the High Arctic. The decline seems to be slower for PCBs, which may indicate continued low-level leakage to the environment from unknown or poorly studied sources.

To the above AMAP summary points, we add the following from the Alaska workshop on Uptake and Effects of Contaminants in Native Foods in Alaska:

• Marine mammals including polar bear, ringed seals, beluga, and walrus probably have elevated levels of PCBs and toxaphene. There are some Alaska data to support this statement, but more is needed. We cannot assume that the trend of decreasing levels of PCBs from eastern to western Canada extends into Alaska, particularly in the Bering Sea. The higher eastern levels of PCBs may be due to a coupling of a regional cooling trend in eastern Canada with atmospheric PCBs from lower latitudes of North America (104).
• DDT and chlordane related contaminants may be important in polar bears and seals (104). DDT concentrations may be lower in the Bering Sea.

• We need data to confirm the Canadian finding that toxaphene predominates in the lower food web of marine organisms and does not become concentrated in polar bears to the same extent as PCBs or some chlordane components (105).
• Canadian results show a large variation in organochlorines in walrus. The presence of many different types of organochlorines in some walrus indicates that the source is not local (and hence of a specific type or types). The variation may be due to differences in diet. Walrus that eat seals may have higher levels. We need Alaska data to test this idea (111).
• It is likely that observed concentrations of PCBs in Baltic ringed seals and in St. Lawrence estuary (Eastern Canada) beluga are 10 to 20 times higher than concentrations in Alaska ringed seal and beluga (118).
• Geographic coverage of levels of persistent organochlorines in marine mammals is not good in Alaska (130). In contrast to the Canadians, we have not studied contaminant levels in most stocks or populations of beluga, ringed seals, walrus, and polar bears. (128)
• We have a poor understanding of how organochlorines move within the marine food web (131).

• We do not have data to know whether the trend of decreasing PCB levels in caribou from eastern to western Canada extends to Alaska (85).
• It is likely, but we need data to confirm, that PCDDs, PCDFs (polycholorinated dibenzodioxins and -furans) and nPCBs (non-ortho PCBs) are extremely low in all caribou herds (86).
• We can’t say, as the Canadians can, that TCDD toxic equivalent concentration (TEQ) levels observed in caribou are comparable to levels observed in domestic animals in Canada (87).
• Geographic coverage of contaminant measures in caribou in Alaska is incomplete (89)
• In northern Canada, fish of primary concern due to their contribution to Native diets include: burbot, lake trout, arctic char, northern pike, and whitefish. We cannot assume that this species are of primary concern in Alaska; rather, all species consumed are of potential concern. Included also should be anadromous fish including salmon. We also cannot assume that PCBs, toxaphene, and mercury are the primary contaminants of concern in freshwater fish (26-29).
• Toxaphene is the major organochlorine contaminant in all freshwater fish in northern Canada. We do not know if this is the case in Alaska (1). It may be true that high toxaphene levels are related to differences in food web structure (i.e. fish eating other fish that are also predators) (31)
• Toxaphene concentrates in fish livers. Burbot with high levels of toxaphene in their livers may have concentrations in their flesh that are comparable to other fish (39).
• There is likely to be a wide variation of PCBs in freshwater fish by location and weight of the fish. In northern Canada, lakes with the highest concentrations of PCBs (e.g. Lake Labarge) have local sources of PCBs and DDT. We need data to know if this pattern is also true in Alaska (33,36).
• Canadian researchers have concluded that they can limit future measurements to non-ortho PCBs unless waste PCB oils or pentachlorophenol use is suspected. They have observed that CB126 accounts for most of the toxic equivalent concentrations in Arctic fish. We cannot assume that these findings apply in Alaska (44,45).
• Geographic coverage of contaminants in freshwater fish in Alaska is poor (60).

• We don’t know how organochlorine levels vary in birds. We cannot say whether the Canadian observation of lower organochlorine levels in the western Arctic extends to Alaska (93).
• Geographic coverage of contaminants in birds in Alaska is poor (96).
• It is likely that mink production is extremely sensitive to PCB contaminants (98).
• We do not have the data to verify the Canadian observation that most organochlorine pesticides and PCB congeners are found at very low levels and that these levels decrease with increasing latitude. At these levels, the Canadians do not suspect any effect on reproduction (100).

• We don’t have data to confirm the Canadian observation of lower levels of organochlorines in Glaucous gulls in the western Arctic (134). Factors affecting organochlorine levels in the Bering Sea may be different, for example.
• Geographic coverage of levels of persistent organochlorines in seabird populations in Alaska is poor (137).

• There is very limited information on levels of organochlorines and aromatic hydrocarbons in marine fish stocks in Alaska waters (140).

• Military sites along Alaska’s coast are likely to be local sources of PCBs and DDT contamination of the nearshore environment. While there is some Alaska data to support this conclusion, more data is needed (150).

• We need to confirm observed trends of declining concentrations of organochlorines in marine mammals and sea birds from the 1970s to the 1980s and a leveling off of concentrations during the mid-1980s to the mid-1990s (153).
• It is likely that the observed decline in SDDT in peregrine falcons is greater than that in arctic sea birds, but we need data to confirm this Canadian finding (155).
• There is limited data on changes in organochlorines such as toxaphene, chlordane, and chlorobenzenes in marine biota. What Canadian data there is for the 1980s and 1990s suggests that there has been no significant decline in concentrations of these contaminants in marine mammals or sea birds. We do not have comparable temporal data for Alaska (157).
• At present, the temporal trend data are too limited to be able to predict future trends because they are based on two or at most three sampling times. By comparison, temporal trend data for contaminants in Lake Ontario lake trout and in various species from the Baltic and from lake Storinveld in northern Sweden are available yearly for a 15-20 year period (168).
• There is clearly a need for well-designed temporal trend studies (170).

• The Canadian Northern Contaminants Program concluded that, with the possible exception of peregrine falcons, contaminant levels or biochemical indicators of effects have not been linked to effects on arctic animals at the individual or population level. The lack of research of this type in Alaska makes it impossible to conclude whether or not there have been effects of contaminants on arctic animals. Local observations of possible effects of contaminants on the environment are needed (173).
• As is usually the case with arctic animals, the lack of experimental dosage/response data continues to limit the ability to interpret concentrations observed in animals (176).
• Canadian researchers have not observed the presence of effects related to toxaphene exposure on fish and ringed seals. We need data to confirm this finding in Alaska (175).
• It may or may not be true in Alaska, as is reported in Canada, that the polar bear is the species with the most significant risk of exposure to PCBs and organochlorine pesticides (182).
• It is likely that Arctic animals with relatively low levels of contaminants may be vulnerable to the biological effects of these contaminants if they have to draw on lipid deposits during fasting or starvation (184).
• It is likely that organochlorine contaminant levels in arctic beluga are 10 to 20 fold lower than in St. Lawrence Estuary (Eastern Canada) beluga. In the case of St. Lawrence beluga, there is preliminary evidence of a link to immune system dysfunction due to high PCB exposure (185).
• We lack the data to confirm the Canadian observation that concentrations of TCDD TEQs in arctic ringed seal and beluga blubber are 3 to 5 times lower than those associated with impaired immune function in harbor seals (187).
• It may be true, but we also lack data to confirm that concentrations of PCBs in blubber lipids of ringed seals are 10 to 20 fold lower than concentrations associated with poor reproductive success in captive harbor seals (188).
• It is likely true that marine mammal females and their offspring may be most vulnerable during mobilization of fats containing contaminants because this mobilization occurs at a crucial point in the growth and development of the young. Overall, the MFO enzyme data in Canada for polar bear and beluga suggest that even the relatively low levels of contaminants present in the arctic animals may have biological effects, especially during years of poor feeding (190).
• Carnivores such as polar bear may be at risk due to consumption of ringed seal tissues, but we need data to support or refute this Canadian finding (193).

• As a result of the Canadian Northern Contaminants Program, the list of priority substances monitored in northern Canada over the past five years is relatively long (including PCB congeners, isomers of HCH, numerous components of technical chlordane and DDT and 25 metals in many samples). We do not have a comparable data set for Alaska. Even in Canada, there are still a number of chemical contaminant groups for which information is quite limited or nonexistent. These groups include PCDD/Fs and non-ortho PCBs, chlorinated napthalenes, chlorinated diphenyl ethers or their brominated analogs (all of which are cytochrome P4501A1 enzyme inducers) (196).
• As in Canada, there are no data in Alaska on toxaphene in terrestrial animals and in waterfowl and seabirds, despite that fact the likelihood that toxaphene may be a major organochlorine contaminant in arctic air, seawater, fishes and marine mammals (198).
• Current methods of quantifying toxaphene may overestimate levels in some species such as marine mammals (199).
• Current use pesticides, a diverse group of less persistent organics, have not been monitored, although recent work indicates that they are likely present in arctic air and snow and terrestrial plants (201).

• In Alaska, there are large spatial and temporal gaps in contaminant data. In contrast, geographic coverage on most contaminants in northern Canada is good (208).
• The complete lack of data over time in Alaska is a major problem. Even where there are measures of contaminants over time, however, changes in methods make it difficult to compare recent and older data (208).
• While studies show that the PCB contamination of terrestrial plants, soils and nearshore sediments and biota in Canada due to pollution from military radar facilities is localized when considered on a broad regional scale, there is a need to confirm these findings in Alaska. There is also a need to determine whether marine mammals frequenting the waters within the general area of these sites as well as terrestrial animals, such as caribou and arctic fox feeding with the impacted zones, have elevated PCB and lead contamination (212).
• It is likely true that individual and community variations in methods of preparing muktuk affect the fat content of this food. These variations should be taken into account in assessments of exposure to organochlorines (214).
• There are few studies of biological effects indicators with arctic animals. There is particularly a need to study biological effects on immunosuppression in mammals at high trophic levels (216).
• More work is needed to confirm observed correlations of non-ortho and mono-ortho PCB concentrations with CYP1A1 activity in polar bear and beluga livers. There is also a need to combine MFO measurements with other biochemical indicators of effects of PCBs such as retinol levels (218).
• Given that some of the persistent organochlorines such as o,p’-DDE, p,p’-DDE and –DDT have estrogen activity, information is needed on steroid and thyroid hormone levels in polar bears and beluga (219).

• The most severe effects of metals on Arctic ecosystems are from local pollution. The nickel-copper smelters on the Kola Peninsula and in the Norilsk region of Russia have severely polluted nearby terrestrial and freshwater environments. In the areas closest to the smelters, the deposition of nickel and copper has, in combination with acidifying emissions, severely damaged the soil and ground vegetation, resulting in an industrial desert. Moreover, the freshwater ecosystem is completely destroyed in at least five water bodies.
• Most of the smelter emissions are deposited very close to their source. However, they are still the major source of circumpolar contamination. Emissions from the Kola Peninsula are the major source of metals in northern Fennoscandian air, and emissions from the Urals and Norilsk are the most important for air concentrations of metals over Alaska and northern Canada.
• Mines are sources of local contamination, but only a few mines have been assessed.
• Metals are taken up by Arctic biota and levels often reflect local geology or local anthropogenic activities. In the circumpolar assessment, the most troubling findings concern mercury and cadmium, as they occur in concentrations that may have health implications for individual animals as well as human consumers.
• Mercury seems to be increasing in both lake and ocean sediments. An increase over the past two to three decades is also evident in livers and kidneys from some marine mammals. This may indicate an increased global flux of mercury, which is deposited in the Arctic because of the cold climate. In some parts of the Arctic, notably Greenland and western Canada, any increase in the mercury load is in addition to high natural levels from the local geology. Several uncertainties about the observed time trends must be resolved before firm conclusions are drawn. For example, the gradients in sediments might be caused by natural processes. For biota, lack of information about the natural variation of mercury levels complicates the interpretation of results.
• Mercury levels in several species of marine mammals seem to be highest in the northwestern part of Canada.
• Mercury biomagnifies in freshwater and in marine ecosystems. However, in all marine animal populations, even the most exposed ones, selenium is abundant enough to detoxify the mercury.
• From a research point of view, further studies of the increase in mercury are a high priority. It is important to verify time trends and also to investigate the sources or processes behind the increase, as well as any biological effects.
• In some areas, cadmium levels are very high both in terrestrial and marine birds and mammals, possibly due to local geology. For example, in reindeer/caribou, the highest cadmium levels have been recorded in the Yukon territory in Canada, which is known to have cadmium-rich geology. Cadmium levels seem to be highest in marine animals from northeastern Canada and Northwest Greenland. For certain age groups and populations of marine birds and mammals, the levels might be high enough to cause kidney damage.
• Lead generally does not pose a threat to Arctic ecosystems because it does not bioaccumulate. Moreover, lead levels have been decreasing for the past two decades.

To the above AMAP summary points, we add the following from the Alaska workshop on Uptake and Effects of Contaminants in Native Foods in Alaska:

• Polar bears, ringed seals, and beluga are likely to have elevated levels of mercury, but we need data to understand how the sedimentary geology differs in different areas off Alaska’s coast as compared with the Canadian Beaufort Sea (120).
• It appears that beluga eliminate mercury from their systems through molting. Canadians found that 20 percent of the total mercury and methylmercury in the skin was lost through molting (126).
• While cadmium concentrations in beluga increase from the western to eastern Canadian Arctic, we cannot assume that the trend extends across the Alaska Beaufort, Chukchi Seas, or into the Bering Sea and Gulf of Alaska. The mineral composition of sediments may differ from those in the western Canadian Arctic (122).
• We don’t have the data to confirm the Canadian finding that cadmium levels in marine mammal livers and kidneys are similar to concentrations in the livers and kidneys of caribou and moose (124). It is probably true that Cadmium concentrations are as high or higher than those of the same or similar species living in temperate waters, but again we need data (123).
• Geographic coverage of levels of heavy metals in marine mammals is not good in Alaska (130). In contrast to the Canadians, we have not studied contaminant levels in most stocks or populations of beluga, ringed seals, walrus, and polar bears. (128)
• We have a poor understanding of how metals move within the marine food web (131).

• We do not have the data necessary to conclude that an observed increase in cadmium levels in caribou kidneys from eastern to western Canada continues into Alaska. We therefore cannot say that the levels in Alaska are comparable to those in northern Quebec and Norway, which is the case in western Canada. The source of cadmium is probably natural and may be related to soil and winter forage (63,64,69).
• It is likely that cadmium levels in caribou kidneys in some Alaska herds are higher than the Canadian guideline of 30 micrograms per gram, but we don’t have the data (65).
• In northern Canada, fish of primary concern due to their contribution to Native diets include: burbot, lake trout, arctic char, northern pike, and whitefish. We cannot assume that this species are of primary concern in Alaska; rather, all species consumed are of potential concern. Included also should be anadromous fish such including salmon. We also cannot assume that PCBs, toxaphene, and mercury are the primary contaminants of concern in freshwater fish (26-29).
• We don’t know if mercury levels in freshwater fish are relatively high or low in Alaska. Higher mercury levels are probably the result of both natural environmental conditions and human activity. Increases in mercury concentrations in sediments in this century may indicate increased human sources (47-55). The correlation of selenium with mercury does not necessarily indicate that the source of mercury is natural.

• We don’t know if the Canadian conclusion that there are low levels of heavy metals in birds applies in Alaska (lead not tested) (94).

• We do not have Alaska data to confirm the Canadian finding that higher concentrations and rates of accumulation of mercury were found in ringed seals and beluga in more recent (1993-94) samples than in earlier collections (1981-83 in eastern Arctic, 1972-73 in the Western Arctic) (159). However, AMAP studies for Eastern Beaufort Sea Polar Bear support the Canadian findings.
• While it may be true that the eastern Canadian arctic finding that cadmium concentrations have showed no change over a 10 year period may apply in Alaska, we need data to confirm it (161).
• There is very limited temporal trend information on heavy metals in the terrestrial and freshwater environments of Alaska (164).

• We lack the data to confirm the Canadian conclusion that Arctic animals have relatively high body burdens of heavy metals and radionuclides compared to similar or related species in temperate regions. We also cannot conclude that Arctic animals may be adapted to relatively high exposure because of the importance of natural sources of these contaminants (178).
• We concur with Canadian researchers that the potential effects of high doses of metals such as cadmium on caribou and beluga are not clear (180).

• Canadian concern with increasing levels of mercury in beluga and ringed seal may be warranted in Alaska as well. It is not clear whether the observed increase is due to human sources, which have been shown to be increasing slowly all this century in dated sediment cores, or is due to some other environment change which is mobilizing mercury (210).
• There are likely high levels of mercury and cadmium in sea birds and marine mammals as observed in Canada. The biological implications for the animals themselves is, however, unknown. Given that the levels of cadmium, for example, are among the highest ever reported in marine mammal tissues, further efforts are needed to examine possible physiological effects (221).

• The Arctic terrestrial system is more vulnerable to radioactive contamination than temperate areas. The exposure of people in the Arctic and subarctic is, for the general population, about five times higher than what would be expected in a temperate area. However, for part of the population the exposure could be more than 100 times higher than expected for similar fallout in temperate areas. The major sources of anthropogenic radionuclides in the Arctic are global fallout from nuclear bomb tests, releases from European nuclear fuel reprocessing plants, and fallout from the Chernobyl accident.
• In addition, discharges from Russian reprocessing plants, underground and underwater nuclear detonations, stores of spent fuel, and dumped waste have contaminated local areas. These latter sources are currently only of minor importance in relation to health risks associated with radioactivity in the Arctic.
• The levels of radionuclides in the Arctic attained their peak values in the 1960s, primarily as a consequence of atmospheric nuclear weapons tests.
• Arctic people receive their major radiation dose from previous weapons explosions, the fallout from which is ingested through terrestrial and freshwater pathways. However, in some areas of Fennoscandia and western Russia, Chernobyl fallout contributes a comparable dose to that of weapons fallout.
• People with a diet high in terrestrial and freshwater foodstuffs receive the highest radiation exposures, from both natural and anthropogenic radionuclides. These foodstuffs include caribou/reindeer, freshwater fish, goat cheese, berries, mushrooms, and lamb. People who eat mostly marine foodstuffs have the lowest doses.
• Polonium from caribou/reindeer dominates the natural radiation dose, whereas cesium-137 from an array of terrestrial food sources is the most important anthropogenic radionuclide.
• The highest average exposures to individuals in indigenous Arctic populations are in Canada and the lowest in Greenland. Consumers of large amounts of caribou/reindeer can have radiation exposures 50 times higher than the average members of their national population.

To the above AMAP summary points, we add the following from the Alaska workshop on Uptake and Effects of Contaminants in Native Foods in Alaska:

• There is some confirmation of naturally occurring potassium 40, polonium 210 and lead 210 in caribou in Alaska. Levels of lead 210 may vary within herds as they do in Canada, but we don’t have data to confirm this (78-82).

• We lack the data to confirm the Canadian conclusion that Arctic animals have relatively high body burdens of radionuclides compared to similar or related species in temperate regions. We also cannot conclude that Arctic animals may be adapted to relatively high exposure because of the importance of natural sources of these contaminants (178).

To the above AMAP and Alaska workshop summary points, we add the following from: Radionuclides in the Arctic Seas from the Soviet Union: Potential Health and Ecological Risks (ANWAP 1997):

• Except for very localized instances in the Kara Sea near dumped reactors and nuclear testing sites, the already existing fallout levels and the Sellafield reprocessing source term now dominate the Arctic.
• Currently, there is no indication that FSU [Former Soviet Union] dumping activities caused elevated concentrations of radionuclides in Alaskan waters. To date, the predicted concentrations of radionuclides in Alaskan waters from FSU dumping are so low in all cases that it is highly unlikely that any significant ecological impacts will occur in any areas outside the immediate Russian disposal sites.
• The potential human health risks associated with ingesting Alaskan seafoods containing radionuclides derived from releases evaluated are extremely low. Those wastes pose no threat to human health; Alaska Native communities, therefore, need not alter any of their dietary habits associated with subsistence foods obtained from Alaskan waters.

• Acidification of Arctic ecosystems is at present a local problem around the nickel-copper smelters on the Kola Peninsula and at Norilsk in Russia. The input of sulfur dioxide into the environment in these areas is extremely high. The air concentrations and the deposition rates are comparable to heavily polluted areas in central Europe. On the Kola Peninsula, the soil in some areas is severely acidified. More information is needd about the Norilsk region.
• The forest ecosystem close to smelters is completely destroyed, and the forest-death area is increasing every year. However, only restricted impacts extend into areas of Finland and Norway that neighbor the Kola Peninsula.
• High deposition of sulfur affects water quality on the Kola Peninsula, and in eastern Finnmark in Norway. In particular, it contributes to pulses of very acidic water in some rivers and streams during spring snowmelt. These acid pulses may be more critical to plants and animals in these waters than annual average pH. In some streams and small lakes , acid-sensitive invertebrates have disappeared. Brown trout is the most vulnerable fish species. Information from the area around Norilsk is not available. Models suggest that continued sulfur dioxide emissions can pose an even greater threat in the future. In particular, some lakes in northern Fennoscandia are vulnerable even to fairly low rates of sulfur deposition.
• Except for the regions affected directly by the smelters (within 200 kilometers), there is no evidence for large-scale soil or water acidification in the Arctic today.
• The sources of acidifying contaminants to the Arctic as a whole are well known. Sulfur dioxide from combustion of fossil fuels and smelting of sulfuric ores is most important. The major source regions are industrial areas further south in Eurasia and North America. Sulfur dioxide reaches the whole Arctic area because unique meteorological conditions allow long-range transport during the polar winter.
• In the atmosphere, sulfur dioxide converts to sulfate aerosols, which can make the sky look hazy, even on clear days. In late winter and early spring, high concentrations of sulfate aerosols reduce visibility throughout the High Arctic. The aerosols have the potential to carry other contaminants. They might also have an impact on regional and global climate, but this aspect of the haze is poorly understood at present. Most of the sulfates that form Arctic haze original from sources in Russia.

• The major anthropogenic source of hydrocarbon contamination in the Arctic is oil and gas development, but several other sources contribute to the load in the environment. These are releases from marine shipping, burning of fossil fuels, long-range transport, and natural oil seeps.
• Accidental oil spills and chronic releases from poorly maintained pipelines and from ships pose the greatest threat from petroleum hydrocarbons. Some severe local and regional problems associated with oil and gas exploration, development, and transportation have already occurred.
• The Arctic environment is more vulnerable to spills than warmer environments because oil breaks down more slowly under cold, dark conditions and because Arctic plants and animals need a longer time to recover from damage. In addition, remedial measures are difficult due to the extreme conditions of cold, ice cover, and winter darkness.
• The environmental threats to the Arctic associated with oil and gas development, production, and transport are primarily local and/or regional and not circumpolar in scale. An important exception is if a large oil spill were to occur coincidentally with large congregations of certain migratory bird and mammal species in Arctic areas. In such cases, a large proportion of a population may suffer.
• Petroleum hydrocarbons are also present in areas not directly affected by spills or prolonged chronic releases. However, in background circumpolar environments, concentrations are relatively low and not of ecological significance. The most highly contaminated areas in the Arctic are certain rivers and estuaries in Russia close to human settlements and industrial or military areas, and in terrestrial/freshwater environments where accidental and operational spills have occurred, such as the area affected by the Usinsk pipeline rupture.
• Polycyclic aromatic hydrocarbons (PAHs) are widespread in the Arctic environment. They come from a variety of sources, including oil, combustion, and biological activity. Measured levels in the environment are generally below the levels thought to cause observable effects in biota, although certain PAHs do reach levels of concern in marine sediments in limited areas.

• Climate change is likely to be more pronounced in the Arctic than in other areas of the world. Feedback mechanisms that can enhance the warming caused by greenhouse gases also make the Arctic important for understanding global climate change.
• Observations from snow cover, and permafrost cores suggest that some warming is already taking place in the Arctic, while temperature records show arming in some areas but cooling in others. Glacial melting, along with warmer water temperatures, has raised sea level globally and this sea-level rise is expected to continue.
• The polar environment is sensitive to changes in temperature and precipitation. This is especially true for marine areas governed by sea ice and terrestrial environments governed by permafrost. Effects on animals include changes in migration routes and changes in species composition. Arctic peoples are directly dependent on climate for access to game animals, fishing, and hunting grounds, and suitable places for settlement.
• Ozone depletion has been more severe in the polar regions than elsewhere in the world. However, Arctic ozone depletion is poorly understood at present, making it difficult to estimate the risk of future ozone holes.
• Ozone depletion leads to increases in ultraviolet radiation that is damaging to living cells. This increase is accentuated in the Arctic because of the reflective snow cover. The most important long-term effect on Arctic ecosystems may be changes in species composition. Effects on humans are discussed in the chapter Pollution and Human Health.
• In regard to climate change, stratospheric ozone depletion, and ultraviolet radiation, there is a clear need for more basic research and monitoring to better understand processes and effects in the Arctic.

To the above AMAP summary points, we add the following from: Report on the FOCI International Workshop on Recent Conditions in the Bering Sea (Macklin 1998):

• (forthcoming)

• Several groups of people in the Arctic are highly exposed to environmental contaminants. Persistent contaminants are carried to the Arctic via long-range transport and accumulate in animals that are used as traditional foods.
• Traditional foods have known nutritional value and there is as yet little conclusive scientific evidence directly linking effects in adults to the levels of exposure that have been observed in the Arctic. Therefore it is not always clear what public health measures should be taken to reduce the exposure of populations who rely on traditional foods.
• The growing brain is particularly sensitive to contaminants, and the influence on fetal development is of special health concern. Methyl mercury and several persistent organic pollutants cross the placental barrier, and in some groups of people PCB and mercury levels in mother’s blood approach and exceed those thought to cause developmental effects in children. Preliminary results indicate that the average umbilical cord blood levels of several persistent organic pollutants and methyl mercury are two- to ten-fold higher in newborns from the AMAP region than in newborns from regions farther south.
• For a number of persistent organic pollutants, health concerns also include child development, reproductive impacts, and effects on the immune system. Several of these effects may be mediated through the hormone-disrupting properties of some contaminants.
• For certain geographic areas, current dietary exposure to persistent organic pollutants, to methyl mercury, and to cadmium are high enough to indicate a need for public health measures. For example, elevated levels of toxaphene, PCBs, and chlordane coupled with current intake scenarios suggest that some indigenous groups are exposed to levels that exceed tolerable daily intakes.
• Human exposure to radionuclides has declined since the cessation of above-ground nuclear weapons testing. However, Arctic peoples are exposed to higher levels of radionuclides than people in the temperate zone. Moreover, radiation from natural sources has resulted in certain indigenous groups having higher radiation risks than the general public.
• The goal of public health actions should be to reduce exposure to contaminants without threatening the social, cultural, spiritual, and physical well-being that is connected to collecting, sharing, and consuming traditional foods. The current traditional diet of Arctic indigenous people provides a substantial proportion of energy and protein requirements as well as most vitamins, essential elements, and minerals. The high consumption of fish and marine mammals may contribute to the lower incidence of heart disease among indigenous peoples in Alaska, Greenland, and Arctic Canada.
• Weighing these known benefits against the suspected, but not yet fully understood, effects of contaminants, the conclusion at present is that consumption of traditional foods should continue. However, consideration should be given to developing dietary advice to promote the use of less-contaminated traditional food items which will also maintain nutritional benefits. Such guidelines should be developed at the local level within the context of local cultures.
• Although there is both scientific and public concern that breast feeding will transfer contaminants from the mother to her child, present knowledge clearly indicates that the known benefits of breast feeding outweigh the currently-known risks from contaminants. To date, there have been no proposals to limit the duration of breast feeding.
• The long-term reduction of exposure to persistent organic pollutants can only be accomplished through international conventions on bans and restrictions in production and use of these substances. The relative importance of natural and anthropogenic sources of heavy metals in the Arctic needs to be determined, and appropriate controls implemented.

To the above AMAP summary points, we add the following from the Alaska workshop on Uptake and Effects of Contaminants in Native Foods in Alaska:

• Native foods are widely consumed within communities. Marine mammals, large ungulates, and fish account for a large proportion of Native foods consumed. Consequently, potential exposure of Alaska Natives to contaminants in Native foods is widespread in Alaska (240)
• Increases in consumption of imported foods by Alaska Natives has been associated with decreased physical activity, obesity, dental caries, anemia, lowered resistance to infection, heart disease, and diabetes (238).
• Dietary survey data in Alaska is limited to 12 communities. While there are data on harvests for many Alaska Native communities, these data do not contain information on variations in consumption patterns among individuals (e.g. consumption of organs, frequency of consumption, method of preparation) (241).
• Consumption of Native foods varies by season and by year. Dietary surveys which measure consumption for 2 or 3 24 hour periods may not reliably estimate consumption of Native foods (244).
• Consumption of Native foods varies by region, income, access to urban centers, and by factors such as age and gender (246).
• Dietary lipids are a concentrated source of energy, act as carriers of fat-soluble vitamins, and are a source of essential fatty acids (polyunsaturated fatty acids that are essential to health but cannot be synthesized by the human body). Fish and marine mammals which form a significant portion of the diet of Alaska Natives contain many n-3 polyunsaturated fatty acids which are not easily found in imported foods. Omega-3 fatty acids are found at high levels in fish and marine mammal tissues and have been associated with a decreased incidence of thrombotic and ischaemic disease (253).
• If consumption of traditional food resources - particularly fish and wildlife- were discontinued, the mineral nutrition of most Arctic populations would be compromised to such an extent that nutritional deficiencies could occur (255).
• Thiamin, riboflavin and niacin intake in the North are reasonably adequate due to the major contributions of these vitamins from traditional meats. Fish and game contribute substantial amounts of vitamin B12 and pantothenic acid. Total intakes of these vitamins are likely higher than in the general US population. Some reports indicate that vitamin A, calcium, and vitamin C may be below recommended intakes (257).
• In Arctic communities, a significant portion of the protein requirements are fulfilled by traditional foods such that limiting the supply of traditionally harvested meats and fish would drastically reduce protein intake (259).
• We do not know if levels of DDT in human tissue in Alaska are, as in the Canadian Arctic, higher than that of southern Canadians and Americans (262).
• We do not know if DDE is higher in the human milk of Alaska Native groups as it is among Inuit in northern Canada (263).
• We do not know if levels of PCBs in the breast milk of at least some Alaska Native groups is higher than that of non-Natives living in southern Canada or the lower-48 states (270).
• A higher incidence of infectious diseases and ear infections among Alaska Native infants may be due to a complicated set of factors. It is unknown whether perinatal exposure to PCBs is one of these factors, nor is the extent of exposure known (271).
• Canadian Inuit show a higher exposure to dioxin-like PCBs than southern Canadians. Factoring this in increases difference in the toxic equivalent burden in the two populations. This type of comparison has not been made in Alaska (273).
• We don’t know enough to conclude that there is a relationship between PCDD/PCDF/coplanar PCB exposure and immunologic and neurodevelopmental alterations associated with breast feeding (275).
• We don’t have data to compare levels of chlordane in the milk of Alaska Native mothers and mothers in the lower 48 (279). Canadian Inuit mothers had chlordane levels 10 times higher than southern Canadian mothers.
• We don’t have data to compare HCB levels in Alaska Native mothers’ and lower 48 mothers’ milk. Canadian Inuit mothers’ milk has HCB levels five to nine times higher than levels seen in southern Canadian mothers’ milk (283).
• Although there are Alaska Native cord blood samples to measure contaminant concentrations, they have not been analyzed (287).
• Although a major source of human exposure to cadmium is smoking, some individuals who frequently eat kidneys of caribou and marine mammals (e.g. once a week year round) may ingest significant amount of cadmium (296). However, only a small percentage of cadmium (about 5 percent) is absorbed through ingestion compared with direct absorption through smoking.
• Smoking may make the kidneys less effective in handling cadmium exposures from frequent consumption of organs, particularly among the elderly and diabetics (299) More study is needed to accept this theory.
• Methylmercury is a potent neurotoxin and the most toxic form of mercury in the environment. Human exposure in the Arctic is almost exclusively through food consumption, especially fish and marine mammals (301).
• We do not have data to confirm the Canadian findings that there is a recent decline in mercury levels in the blood of Inuit and Dene newborns in the NWT (304).
• The amount of radionuclides in the Arctic environment is generally about the same as, or lower then, levels found in the temperate zone (307).
• The greatest exposures to radionuclides occurred in the 1950s and 1960s (e.g. strontium 90). The long term effects of Strontium 90 in bone perhaps interacting with exposures to organochlorines is not known. Of all radionuclides, lead-210 and polonium-210, which are natural in origin, may make the greatest contribution to current human radiation doses in the Arctic. However, the greatest exposures to radionuclides may come from improperly used or maintained radiological equipment. Both lead-210 and polonium-210 occur in nature as airborne particles and rend to settle out on vegetation (i.e. lichens) thereby entering the terrestrial food chain (lichens-caribou-humans) (308). We should also consider polonium-210 levels in fish.
• Residents in Arctic communities may be receiving up to 10 mSv of Po-210 per year through dietary sources compared with normal background doses of about 2 mSv. This has likely been occurring in the Arctic for several thousand years. The effects of exposure may be increased by smoking. (311)
• Of the anthropogenic radionuclides, the two main isotopes of radiocesium (cesium-137 and cesium-134) are considered to be of greatest concern in Arctic environment. Levels of radiocesium in Arctic residents have declined from about 450 Bq-kg in 1965 to roughly 10 Bq-kg in 1990. The effects of exposures to Strontium 90 in the 1950s and 60s, however, may be important, but we don’t know (312).
• Feather moss (Hylocomium splendens ), and lichens can be used to monitor atmospheric deposition of radionuclides and heavy metals. They can help to distinguish between atmospheric sources of these pollutants and rivers.
• Risk determination for contaminants in Native food involves a consideration of the type and amount of food consumed and the sociocultural, nutritional, economic, and spiritual benefits associated with Native foods (315)
• Risk management decisions must involve the community and must take all aspects into account to arrive at an option that will be the most protective and least detrimental to the community (316).
• Regardless of the decision taken, some health risks associated with exposure to contaminants may remain. In the Arctic, these risks and benefits often pose a large and confusing public, moral and political dilemma (318)
• Risk management is an evolving process subject to change as new information about the situation is learned and assessed. The approach must be continually modified to suit each situation and each community and the advice monitored to ensure it is providing the best possible health outcome (319).
• In Alaska Native communities, advising against Native food consumption is also to advise against hunting and fishing. To the extent that aboriginal identity and the collective sense of well-being is based on subsistence as a social system and as an activity, as well as a dietary staple, then loss of confidence in Native food undermines confidence in identity and society (321)
• If not released with proper communication and consultation, advisories related to Native food can also result in individual estimations of risk that are often based on untested assumptions and are frequently wrong, leading to harmful and undesirable social and economic results (323)
• While Alaska Natives are unlikely to abandon their harvests of Native foods, the lack of proper communication and consultation can seriously compromise the contribution of harvests to Native well-being and the integrity of the community. Hunters may stop sharing harvests, for example, if they fear that they will make other people sick. (324)
• As such, risk management decisions must be carefully considered and must be implemented in ways that minimize the extent to which nutritional and sociocultural aspects of Aboriginal societies are compromised (326)
• Regardless of the difficulties in the processes of risk assessment and risk management and the different views on their adequacy, we must be guided by one objective. Risk assessment and management decisions are undertaken to serve public health. They must be our "best estimate" and seen in the context on which they were created - an imperfect and ever-changing data base (327)

• Perception of risk in the Alaska, as in many communities, differs between the public experts. A lack of straightforward and credible information about toxicity and safe levels leads to unnecessary anxiety. This anxiety in turn can disrupt Native food harvest and consumption. The goal should be to provide clear information that will minimize unnecessary anxiety and alert people to real problems where they exist (330).
• Transfer of accurate and complete information via good communication plans may help limit the social and cultural effects resulting from the presence of contaminants in traditional food. If this does not occur, people will be forced to draw their own conclusions and will act accordingly based on their perceptions of the situation (333)
• In Arctic communities, communication is most effective when it is interpersonal and face-to-face. It should be a two-way flow of information where the opportunity for feedback is maximized (334)
• Communication should occur from the onset of a study and should be an ongoing process through to the reporting of findings and the development of remedial options. The best studies and the best solutions to local contaminant problems are developed with and by the community (336)

• There are many recognized advantages of nursing for both infants and for mothers, including improved nutrition, increased resistance to infection, protection against allergy, better parent-child relationships, and possibly a degree of protection of the mother against breast cancer. In the Arctic, alternatives to breast-feeding, such as infant formula, can be difficult to obtain (due to availability and affordability) and can pose difficulties with respect to the maintenance of hygiene in cases where the water supply is compromised (339)
• We do not have the data necessary to assess the Canadian conclusion that the organochlorines of primary health concern at this time for Alaska Natives consuming marine mammals as a major component of their diet are chlordane, toxaphene, and PCBs. In Canada, exposures in the eastern region are higher than in the western region (341)
• Canadians concluded that Dene/Metis, exposure to OCs is in general below a level of concern. However levels of chlordane and toxaphene exposure are elevated in some individuals and are a cause for concern if individual exposures are elevated on a regular basis. We lack the necessary data in Alaska to assess this conclusion with regard to Alaska Natives who do not consume marine mammals as a major component of their diet (342).
• The developing fetus and breast fed infant are likely to be more sensitive to the effects of OCs than adults and are the age group at greatest risk in the Arctic. Fetus/infant intakes of dioxins and furans, PCBs, toxaphene and HCB through human cord blood/milk are of primary concern even though the toxic effects that might occur are uncertain. In consideration of this uncertainty, the extensive knowledge of the benefits of breast-feeding are a strong rationale for Alaska Native women eating substantial quantities of marine mammals to continue to breast feed unless told otherwise by their health care provider. However, this advice should be decision of Alaska Native communities made in the context of a collaborative program of research and assessment (344)
• Risk management decisions must continue to be developed in cooperation with communities to reduce exposures and to sustain traditional ways (348)
• Current levels of lead in the Arctic do not pose a significant threat to health and, based on declining emissions of lead globally, are not likely to pose a threat to health. When there is a potential source of lead contamination, however, cord blood and infant blood monitoring should occur to ensure local or regional lead levels are not increasing. (350).
• Cadmium intakes by non-smokers in the Alaska are likely to be low and similar to intakes reported in southern Canada (353).
• Smokers are likely to have 20 to 30 times higher mean blood levels of cadmium than non-smokers. These intake levels exceed the current WHO TDI value several-fold and are not related to consumption of Native food (355).
• We do not have adult blood mercury measurements to assess the risk of mercury exposure (25). Canadian results show that some Native populations are in the 5 percent risk range for neonatal neurological damage. Umbilical cord blood level measurements could be used to screen for exposures (357).
• It is likely that Alaska Native consumers of Native foods are exposed to an approximately seven-fold higher radiation dose than non-consumers of traditional food. More than 95% of this increased radiation dose is due to the bioaccumulation of natural radionuclides in the food chain (363)
• This increased radiation dose gives consumers of Native foods a cancer risk that is approximately 10% higher than that compared with consumers of a southern diet. In Canada, this increased risk is in fact not seen in NWT Inuit cancer statistics where Inuit have a significantly lower rate of all cancers, with the exception of lung cancer, than the Canadian population. In Alaska, there is a higher incidence of some cancers (e.g. stomach cancer), but this may be unrelated (365).