State of Contamination of Northern Canada and Greenland

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Environmental Health Service

Community Health Department

Laval University Hospital Centre

June 1992

INSPO - Montréal

3 5567 ÛOOÔO 3696

1!

Institut national de santé publique du Québec 4835, avenue Christophe-Colomb, bureau 200

Montréal (Québec) H2J3G8

Tél.: (514) 597-0606

Centre de documentation

State of Contamination of Northern

Canada and Greenland

Final report

English version

By

Hélène Careau, Gr. Dpi. Éric Dewailly, m.d., Ph.D.

Anne Vézina, M. Se. Pierre Ayotte.Ph.D.

Denis Gauvin, M.Sc.

Environmental Health Service Community Health Department

Laval University Hospital Centre

JUNE 1992

Disponible en version française. This document is the translation of the original document:

Careau, H., Dewailly, É., Vézina, A., Ayotte, P., Gauvin, D. 1992. " État de la contamination du Canada nordique et du Groenland." Département de santé communautaire du Centre hospitalier de l'Université Laval. Juin 1992.

Legal Deposit - 2nd trimester 1993 Bibliothèque nationale du Québec

National Library of Canada ISBN 2-921304-42-2

TABLE OF CONTENTS

Page

LIST OF TABLES v

LIST OF FIGURES v i i i

ACKNOWLEDGMENTS x i

INTRODUCTION 1

PART I METHODS

1.1 Study area 5

1.2 Database 5

1.3 Statistical Considerations 9

1.4 Major Contaminants 10

1.5 Northern Food Species 13

1.5.1 Marine Mammals 16 1.5.2 Terrestrial Mammal 19 1.5.3 Waterfowl 19 1.5.4 Fish 20

PART II THE FOOD CHAIN

2.1 Food Chains and Trophic Levels 25

2.2 Accumulation of Contaminants 25

2.2.1 Modes of Exposure 25 2.2.2 Properties of Contaminants 26 2.2.3 Other Factors 26

2.3 Northern Aquatic Food Chains 27

2.3.1 Prey Consumed by Northern Food Species 27

2.4 Example of a Food Chain 30

PART III ANIMAL CONTAMINATION

3.1 TCDD 35

3.2 Aldrin and Dieldrin 37

3.2.1 Aldrin 37

3.2.2 Dieldrin 41 3.2.2.1 Mammals 41 3.2.2.2 Fish 46 3.2.2.3 Waterfowl 46

3.3 Chlordane 46 3.3.1 Mammals 50 3.3.2 Fish 55 3.3.3 Waterfowl 55

3.4 Lindane 55

3.5 Endrin 59 3.5.1 Mammals 59 3.5.2 Fish 59

3.6 Mercury 62

3.6.1 Mercury 62 3.6.1.1 Mammals 62 3.6.1.2 Fish 66 3.6.1.3 Waterfowl 69

3.6.2 Methylmercury 69

3.7 DDT 74 3.7.1 Mammals 74 3.7.2 Fish 77 3.7.3 Waterfowl 82

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3.8 Heptachlor/heptachlor epoxide 82

3.8.1 Heptachlor 82

3.8.2 Heptachlor epoxide 85 3.8.2.1 Mammals 85 3.8.2.2 Fish 85

3.9 HCB 8 5 3.9.1 Mammals 89 3.9.2 Fish """" 94 3.9.3 Waterfowl 94

3.10 Cadmium 97 3.10.1 Mammals 97 3.10.2 Fish 100 3.10.3 Waterfowl 100

3.11 PCB 1 0 3

3.11.1 X PCB 103 3.11.1.1 Mammals 103 3.11.1.2 Fish 105 3.11.1.3 Waterfowl 109

3.11.2 Aroclor 109

3.12 Lead m

3.13 Methoxychlor 111

PART IV HUMAN CONTAMINATION

4.1 Contaminants 117

4.1.1 Heavy Metals 117 4.1.1.1 Mercury 117 4.1.1.2 Cadmium 124 4.1.1.3 Lead 127

4.1.2 Organochlorines 127

4.2 Dietary Contaminant Intake 133

4.3 Risk from Exposure to Chlorinated Pesticides... 140

ix

CONCLUSION AND RECOMMENDATIONS

REFERENCES

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LIST OF TABLES

Table p a g e

1.1 Major contaminants ranked according to their acceptable daily doses in micrograms per kilogram of body weight 11

1.2 Daily intake of the main wildlife species by the Inuit of Broughton Island 14

1.3 List of main marine mammal, waterfowl, and fish species

consumed by native people in each region 15

1.4 List of main food species „ 17

3.1 Levels of 2,3,7,8-TCDD in mammals 36

3.2 Levels of aldrin in mammals 39

3.3 Levels of aldrin in fish 40

3.4 Levels of dieldrin in mammals 43

3.5 Levels of dieldrin in fish 47

3.6 Levels of dieldrin in waterfowl 49

3.7 Levels of total chlordane in mammals 51

3.8 Levels of total chlordane in fish 56

3.9 Levels of total chlordane in waterfowl 58

3.10 Levels of endrin in mammals 60

3.11 Levels of endrin in fish 61

3.12 Levels of total mercury in mammals 63

3.13 Levels of total mercury in fish 67

3.14 Levels of total mercury in waterfowl 70

3.15 Levels of methylmercury in mammals 71

3.16 Levels of methylmercury in waterfowl 72

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3.17 Levels of total DDT in mammals 76

3.18 Levels of total DDT in fish 80

3.19 Levels of total DDT in waterfowl 83

3.20 Levels of heptachlor in mammals 84

3.21 Levels of heptachlor in fish 86

3.22 Levels of heptachlor epoxide in mammals 87

3.23 Levels of heptachlor epoxide in fish 88

3.24 Levels of HCB in mammals 90

3.25 Levels of HCB in fish 95

3.26 Levels of HCB in waterfowl 96

3.27 Levels of cadmium in mammals 98

3.28 Levels of cadmium in fish 101

3.29 Levels of cadmium in waterfowl 102

3.30 Levels of total PCB in mammals 104

3.31 Levels of total PCB in fish 108

3.32 Levels of total PCB in waterfowl 110

3.33 Levels of Aroclor 1260 in mammals 112

3.34 Levels of lead in mammals 113

4.1 Levels of methylmercury in the hair and blood of arctic native populations 119

4.2 Levels of mercury in the hair of Crees from the Hudson region for 1987 122

4.3 Levels of mercury in the hair and blood of Inuit from the Ungava region for 1983 123

4.4 Levels of mercury in the blood of Inuit from Greenland 125

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4.5 Levels of cadmium in the hair, blood and urine of Inuit from Northern Canada and Greenland 126

4.6 Levels of lead in the blood of Inuit from Greenland and the

Canadian Arctic 128

4.7 Levels of PCB in Inuit from Northern Canada and Greenland 129

4.8 Levels of organochlorinated pesticides in Inuit from Northern Quebec and Greenland 131

4.9 Levels of dibenzofurans and dioxins in the milk fat of 40 Inuit women from the Hudson and Ungava regions 132

4.10 Estimates of daily intake of 4 organochlorines in the Inuit community of Broughton Island 141

4.11 Daily intake (Dl) and Acceptable Daily Intake (ADI) of 4 organochlorines 142

ix

LIST OF FIGURES

Figure Page

1.1 Delimitations of the ten regions 6

1.2 Example of a database record 8

2.1 Biomagnification of dieldrin in the arctic aquatic food chain 31

3.1 Geographical variations in the mean levels of 2,3,7,8-TCDD

in the fatty tissues of the ringed seal and of the polar bear 38

3.2 Mean levels of dieldrin in the fatty tissues of mammals 42

3.3 Mean levels of dieldrin in the liver and lipids of the polar bear 44

3.4 Geographical variations in the mean levels of dieldrin in the

fatty tissues of the ringed seal, beluga and polar bear 45

3.5 Mean levels of dieldrin in the muscle of fish species 48

3.6 Mean levels of total chlordane in the fatty tissues of mammals 52

3.7 Mean levels of total chlordane in the liver and in the lipids of the polar bear 53 3.8 Geographical variations in the mean levels of total chlordane

in the fatty tissues of the polar bear, beluga and ringed seal 54

3.9 Mean levels of total chlordane in the muscle of fish species 57

3.10 Mean levels of total mercury in the tissues of mammals from Greenland 64

3.11 Geographical variations in the mean levels of total mercury in the liver of the polar bear and beluga 65

3.12 Comparison of the mean levels of total mercury in the muscle of fish from dammed and natural areas 68

3.13 Mean levels of methylmercury in the tissues of mammals

from Greenland 73

3.14 Mean levels of total DDT in the fatty tissues of mammals 75

3.15 Mean levels of total DDT in the tissues of the polar bear 78

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3.16 Geographical variations in the mean levels of total DDT in the

fatty tissues of the beluga and polar bear 79

3.17 Mean levels of total DDT in the muscle of fish 81

3.18 Mean levels of HCB in the fatty tissues of the mammals 91 3.19 Geographical variations in the mean levels of HCB in the fatty

tissues of the beluga and polar bear 92

3.20 Mean levels of HCB in the liver of mammals 93

3.21 Geographical variations in the mean levels of cadmium in the liver of the beluga and polar bear 99

3.22 Geographical variations in the mean levels of total PCBs in the

fatty tissues of the polar bear, beluga and ringed seal 106

3.23 Mean levels of total PCBs in the fatty tissues of mammals 107

3.24 Mean levels of lead in the tissues of beluga 114

4.1 Localization of native villages 113 4.2 Temporal evolution of methylmercury in the hair of Inuit from

Clyde River, Baffin region 121

4.3 Quantity of food as a function of the levels of 2,3,7,8-TCDD measured in the tissues of the various species that can be consumed in a day without exceeding an ADI of 70 pg/day 134

4.4 Quantity of food as a function of the levels of dieldrin measured in the tissues of the various species that can be consumed in a day without exceeding an ADI of 3.5 p.g/day 135

4.5 Quantity of food as a function of the levels of total chlordane measured in the tissues of the various species that can be consumed in a day without exceeding an ADI of 4.2 |ig/day 136

4.6 Quantity of food as a function of the levels of mercury measured in the tissues of the various species that can be consumed in a day without exceeding an ADI of 21 ng/day 137

4.7 Quantity of food as a function of the levels of total DDT measured in the tissues of the various species that can be consumed in a day without exceeding an ADI of 35 ng/day 138

ix

4.8 Quantity of food as a function of the levels of total PCB measured in the tissues of the various species that can be consumed in a day without exceeding an ADI of 70 |ig/day 139

x

ACKNOWLEDGEMENTS

We would like to express our thanks: to Hydro-Quebec for its financial assistance and for access to their data banks, especially Marcel Laperle and Martin Pérusse; to the Department of Indian Affairs and Northern Development who also financially participated through the Arctic Environmental Strategy (AES) -- Contaminants Program; to Health and Welfare Canada; and to the Government of Northwest Territories-Health who revised and helped to finance this translation. We also wish to thank the Groupe Environnement Shooner inc. who participated in setting up the database and in providing background maps. We are grateful to the people working in the field of environmental contamination who let us use their data, especially the researchers at the Freshwater Institute in Winnipeg and at the Canadian Wildlife Service in Hull. We also wish to express our thanks to our cartographer Laurence Morissette for her patience and good work and to Anne Vézina who translated this report.

\ viii ix

INTRODUCTION

It is only in the last decades that mankind has been forced to acknowledge the contamination problems caused by the overutilization and the largely uncontrolled discharge of thousands of chemicals in the environment. Over time, these products have made their way into the various food chains of the earth's ecosystems.

Contamination of the food chains has not spared northern regions. It is now recognized that the Arctic fauna also has a tendency to accumulate potentially toxic substances in their tissues. The main contaminants detected to date are organochlorines and heavy metals. In addition to presenting dangers to the animal populations, the bioaccumulation of these products may also cause health problems to the people in northern communities who rely heavily on fish and game as a food source.

The objectives of this report are to review the contaminant levels in the species which are part of the aquatic food chains of northern Canada and of Greenland, and to identify which type of data are missing. All together, fourteen contaminants have been selected according to their toxicity, while fourteen animal species and five animal tissues have been chosen for their importance in the diet of native people. Using the information stored in the database set up for this project, we estimate the dietary intake of organochlorines for the Inuit of Broughton Island, a community whose food habits are known. This example illustrates the usefulness of the database in analyzing, on a preliminary basis, the health risks to which the northern populations who harvest a good proportion of their food, are exposed.

Finally, after having identified the gaps in our knowledge regarding the extent of the contamination of the North, we formulate recommendations which may serve as guidelines for future research.

214

PART I

METHODS

1 .1 Study Area

The Community Health Department of the Laval University Hospital Centre was originally given the mandate of reviewing the contamination of the aquatic food chain in Northern Quebec, but it was decided early on to extend the area covered to Northern Canada, including the Northwest and Yukon Territories and Greenland. A larger study area, would allow us to look at geographical variations in the levels of contaminants present in the various animal populations and native communities inhabiting these territories.

The study area was then divided into ten regions in order to facilitate the compilation and analysis of the data (Figure 1.1). Delimitation of some regions reflects existing boundaries, while others have been changed. For example, the Yukon Territory and the Northwest Territories' administrative regions of Inuvik and Ft. Smith are the models for the regions bearing their name. The northern limit of the Northwest Territories' administrative region of Kitikmeot has been slightly modified to avoid cutting islands in two, while the Baffin administrative region was divided in two geographically distinct regions, Baffin and Ellesmere. Finally, the limits of the Keewatin administrative region, as well as the Hudson and Ungava regions, were drawn to include the various hydrographical basins. The region of Greenland covers the island of Greenland and its territorial waters.

The maps shown in this report are based on the Energy Mines and Resources maps (1:7,500,000).

1 . 2 Database

We conducted an exhaustive literature search and gathered all the available data on the levels of contaminants in the people and animal species which are part of the northern aquatic food chains. Unpublished data was also obtained from researchers and some organizations. The data were stored in a database running on the 4th DIMENSION software. Some data may have been missing at the time of

216

writing this report.

The 4th DIMENSION software was chosen because it is user-friendly, flexible, compatible with other software, and because it offers the possibility of incorporating statistical formulas. It is also easy to enter data and to search through the database.

The data can also be readily transferred to a Geographical Information System (GIS), such as MAPINFO™. A formula to convert the lat-long values into the coordinates of a Lambert Conformai Conic Projection is included in the database for transfer into a GIS.

The type of data recorded is presented in Figure 1.2. The variables included were selected on the basis of the information available in the scientific literature and of the needs that arose during compilation. In each record we give the name of the species, the region, the sample site, the authors, the year of publication, the latitude and longitude. The other variables pertain to the samples themselves. They include type of tissue, percentage of water and lipids, age and sex of the individuals, number of samples, name of the contaminant, mean concentration, units, type of mean (arithmetic or geometric), standard deviation, minimum and maximum values, method of analysis, sampling date and space for comments.

All the samples collected after 1970 are included in the database. For the present report, however, we cover only the data gathered after 1980 since the number of studies on contaminants sharply increased around that time. In addition, the methods of analysis used in the seventies are not as reliable and precise as the more recent ones. The annex can be consulted for more detail on the data used in generating the results presented in this report.

A quality control index was not included given the difficulty of comparing the data. In Canada, however, most of the work in the field of marine contamination is done at a few specialized laboratories, ensuring a certain consistency in the results. Furthermore, interlaboratory comparison programs are now widespread.

There are over 10,000 records in the database, covering more than 80 species. The Latin, French and English name of each species are listed in a file

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The contaminant levels are expressed as wet weight, lipid weight or dry weight basis. In the few cases where the concentrations in blubber are expressed as lipid weight we treat them, in this report, as wet weight, since lipids make up between 75% to 95% of the weight of the tissue.

Most of the concentrations of organochlorines and metals are calculated on a wet weight and dry weight basis respectively, although most metal levels in fish are expressed on a wet weight basis. Conversion factors to calculate a wet weight from a dry weight, have been described for the beluga and narwhal. Dry weights are multiplied by 0.277 and 0.2668 for the muscle and liver of the beluga (Wagemann et al., 1991), and 0.281 and 0.257 for the muscle and liver of the narwhal respectively (Wagemann et al., 1983).

1.3 Statistical Considerations

The levels of the various contaminants are, in the vast majority of cases, expressed as arithmetic means and as such those values cannot be averaged without weighing for "n". In this report "nM represents the number of analyses, a value which may but does not necessarily represent the number of individuals. It can refer to the number of individuals tested (i.e. one individual per analysis) or to a pool of individuals (i.e. many individuals per analysis). In the database, it is specified when the analysis was done on a pool of individuals. When no data is available a is inserted in the tables. One must not conclude, however, that contaminants are not present in the organisms. The geographic absence of a species from one of the regions in question, is noted with the mention "absent"

To calculate the mean of the means which are presented in this report, the appropriate statistical formula was incorporated in the database. A standard

viii ix

deviation for the mean of the means is also generated. When only the detection limit is available, the mean is calculated using that value even though it tends to slightly overestimate the results.

While most authors express their results as arithmetic means, some of them utilize geometric means. The latter, however, cannot be averaged. When such cases arose, we used the same formula as for the mean of arithmetic means in order to generate an estimate of the mean of geometric means. These estimates are identified as such. It should be kept in mind, however, that these estimates have no statistical value and that no standard deviation can be derived. When the untransformed data follow a normal distribution, the two types of means are close to each other. When the distribution is skewed to the left, the geometric mean is lower than the arithmetic mean, and when it is skewed to the right the reverse is true. Unless otherwise stated, the data are expressed as arithmetic means.

1.4 Major contaminants

For our analysis, we chose the fourteen most important contaminants among those included in the database (Table 1.1). We selected the substances most toxic to humans and which were the most susceptible to exceed the reference dose (RfD) or the Acceptable Daily Intake (ADI).

The RfD is emitted by different governmental agencies such as Health and Welfare Canada (HWC), the U.S. Environmental Protection Agency (USEPA) or the Agency for Toxic Substances and Disease Registry (ATSDR). These various agencies follow similar methods to determine the ADI.

A Lowest Observed Adverse Effect Level (LOAEL), the lowest dose producing an effect, or a No Observed Adverse Effect Level (NOAEL), the highest dose producing no effect, are estimated after a review of the toxicological literature.

\

TABLE 1.1 Major contaminants ranked according to their acceptable daily intake doses in micrograms per kilogram of body weight.

TCDD 0.000001 (ATSDR, 89)

Aldrin Dieldrin Chlordane Lindane Endrin Mercury Methyl mercury DDT Heptachlor HCB Cadmium PCB (Aroclor 1260) PCB (Aroclor 1248) Lead Methoxychlor

0.03 0.05 0.06 0.3 0.3 0.3 0.3 0.5 0.5 0.8 1.0 1.0 1.0 3.5 5.0

(EPA, 88) (EPA, 90) (EPA, 89) (EPA, 88) (EPA, 88) (ATSDR, 89) (EPA, 89) (EPA, 87) (EPA, 87) (EPA, 89) (EPA, 89) (EPA, 84) (HWC, 89) (EPA, 87) (EPA, 90)

ATSDR: Agency for Toxic Substances and Disease Registry EPA: Environmental Protection Agency HWC: Health and Welfare Canada

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The LOAEL and the NOAEL are then divided by one or several safety factors of 10 to account for the uncertainties attached to these values (USEPA, 1991; IRIS database).

A factor of 10 is used when the NOAEL is derived from studies on the chronic or sub-chronic effects of the product on humans.

Another factor of 10 is used when data on humans are not available but good toxicological studies have identified a NOAEL for one or many animal species.

An additional factor of 10 is used when only data on sub-chronic exposure on laboratory animals are available.

Another safety factor of 10 is used when a RfD is determined from a LOAEL, rather than a NOAEL.

The NOAEL or LOAEL is divided by the appropriate safety factor in order to determine the reference dose. The factor may vary from 10 to 10,000 according to the number of security factors which apply.

ADI = NOAEL or LOAEL = mg/kg/day SF

For the carcinogenic substances, we refer to virtually safe doses, which are doses associated with the additional risk of causing one cancer among 1,000,000 people exposed for 70 years. These doses are extrapolated using a multistage extrapolation model from tumor incidences observed in laboratory animals.

\

1.5 Northern Food Species

Northern native populations still rely, to various degrees, on the harvesting of wildlife as a source of food. They are therefore at a greater risk than the general population of accumulating contaminants through their diet. Wildlife species, especially the marine ones, are rich in lipids and tend to accumulate contaminants. Human exposure varies with the quantity and type of wildlife eaten. Studies on the consumption of traditional foods are rare. One study was done in Broughton Island, a community with one of the highest per capita intake of native foods on Baffin Island (Table 1.2).

Compared to the harvest surveys done previously in the same community, the Broughton Island study indicates that harvest data are a good indication of the diet but tend to overestimate consumption (Kinloch et al., 1990). They are not accurate because all the harvested food is not eaten and the values used to convert the number of animals into edible biomass do not account for the differences in weight according to age, sex, region and time of harvest. Nevertheless, harvest surveys are often the only source of information and we used them to rank the main food species according to their relative importance in the diet (Table 1.3).

Information for the Baffin, Ellesmere, Keewatin and Kitikmeot regions comes from the harvest studies summarized in Wong (1985). For Northern Quebec, we used the data collected by the James Bay and Northern Quebec Native Harvesting Research Committee (CRRA, 1982; 1988). The latter established the harvest levels which are guaranteed in the James Bay Convention and reserved to the Crees and inuit.

Information for the other regions comes from more or less detailed studies of harvest data: Dimitrov and Weinstein (1984) for the Yukon; Corkum and McCart (1981) for Inuvik; Kapel and Petersen (1982) for Greenland; and Alton Mackey and Orr (1987) for Labrador. The data on Labrador native communities are presented separately from those from Ungava.

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Table 1.2 Daily intake of the main wildlife species by the Inuit of Broughton Island (Taken from Kuhnlein, 1989).

Species Tissue Daily intake (g/pers)

Ringed seal muscle 260

blubber 23

liver 4

Bearded seal muscle 10

Narwhal muktuk 74

muscle 22

blubber 8

Beluga muktuk 2

Walrus muscle 24

blubber 6

Arctic char muscle 65

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When available, the harvest data were converted into edible weight using the conversion factors given by the authors. These values were then divided by the total population in each community, even though the harvested food is not equally distributed among its residents. Since the results vary a lot from one community to the other, we present the minimium and maximum values calculated for each region and for the 14 species chosen as the most representative of the northern native diet (Table 1.4).

1 .5 .1 Marine mammals

Ringed seal

The ringed seal, Phoca hispida, is by far the most common seal in the Arctic. It is the main marine mammal hunted by the Inuit. In Northern Quebec, the Inuit consume between 10 to 158 g/pers/day, whereas this species is less important for the Crees who eat between 0.5 to 20 g/pers/day. In Labrador, the consumption varies between 25 to 41 g/pers/day and in the Arctic it oscillates between 50 to 510 g/pers/day in Baffin, 15 to 75 g/pers/day in Keewatin and 90 to 295 g/pers/day in Ellesmere. The blubber is used in the preparation of "misirak", a dip for meats which is very popular with the Inuit.

Bearded seal

The bearded seal, Erignathus barbatus, is a solitary animal found mostly in shallow waters. Although less numerous than the ringed seal, the bearded seal is sought for its size which is, on average, one meter longer than the former. In Northern Quebec, it is hunted only in the Ungava region and even if it represents one thirteenth of the quantity of ringed seals harvested, the contribution in terms of food is high, between 32 to 180 g/pers/day. In Labrador, the mean consumption is 5 g/pers/day. In the Arctic, the quantity eaten varies between 5 to 110 g/pers/day in Baffin, 4 to 45 g/pers/day in Keewatin and 30 to 45 g/pers/day in the Ellesmere region.

\

TABLE 1.4 List of main food species

Ringed seal (Phoca hispida ) Bearded seal ( Erignathus barbatus ) Harp seal (Pagophilus groenlandicus ) Walrus (Odobenus rosmarus) Beluga (Delphinapterus leucas ) Narwhal (Monodon monoceros ) Polar bear (Ursus maritimus ) Canada goose (Branta canadensis ) Common eider (Somateria mollissima ) Arctic char (Salvelinus alpinus ) Lake trout (Salvelinus namaycush ) Lake whitefish (Coregonus clupeaformis ) Rock cod ( Gadusogac ) Burbot (Lotalota)

viii ix

Harp seal

Harp seals, Pagophilus groenlandicus, give birth to their pups in March on the sea ice off the coast of Newfoundland and in the Gulf of St. Lawrence. In summer, they migrate north to the Eastern Arctic. They are rarely seen in the Hudson and Ungava Bays. In Labrador, between 2 to 9 g/pers/day are eaten. In the Arctic, the Inuit consume between 4 to 595 g/pers/day in Baffin, 3 to 7 g/pers/day in Keewatin and 235 g/pers/day in Grise Fjord in the Ellesmere region.

Beluga

The skin of the beluga, Delphinapterus leucas, is a delicacy called "muktuk" or "maktak". The blubber attached to the skin represents ten precent of the weight of muktuk. In the Ungava region, quotas limit the catch to between 10 to 30 belugas per hunter, depending on the community (DFO, 1990). At most, it represents 195 g/pers/day. In the Arctic, consumption varies between 2 to 145 g/pers/day in Baffin, 60 to 360 g/pers/day in Keewatin and 55 to 115 g/pers/day in Ellesmere. However, hunters often remove nothing more than the skin and meat fillets (Smith, 1980). In view of this, the quantities eaten are probably overestimated. The blubber is also used in the preparation of "misirak".

Narwhal

The narwhal, Monodon monoceros, is only found in certain regions of the Eastern Arctic. The Inuit of Baffin eat between 2 to 265 g/pers/day. In Grise Fjord, Ellesmere, and in Repulse Bay, Keewatin, 30 to 115 g/pers/day are eaten respectively.

Walrus

Hudson Bay is the southern limit of the walrus, Odobenus rosmarus. The Inuit eat between 1 to 25 g/pers/day of the animal's edible weight. In the Arctic, it amounts to between 3 to 70 g/pers/day in Baffin, 23 to 53 g/pers/day in the Keewatin communities of Chesterfield Inlet and Coral Harbor, and 70 g/pers/day in Grise Fjord in the region of Ellesmere.

\

1.5.2 Terrestrial Mammal

Polar bear

The most southern populations of polar bears, Ursus maritimus, are found on the coasts of the Hudson and James Bays. In Quebec, the Inuit are guaranteed 56 individuals per community, which represents between 1 to 16 g/pers/day of food. In the Arctic, the consumption varies between 3 to 45 g/pers/day in Baffin, 65 to 74 g/pers/day in Ellesmere, and 1 to 35 g/pers/day in Keewatin.

1.5.3 Waterfowl

Canada goose

In Northern Quebec, the Canada goose, Branta canadensis, is mostly found in

the coastal areas of the Hudson and James Bays. During the spring and fall migrations, the Cree hunters bring back between 4 to 105 g/pers/day of food, while for the Inuit the quantities vary between 10 to 75 g/pers/day. In Labrador, consumption is about 6 g/pers/day. In the Arctic, it is under 1 g/pers/day in the Baffin and Keewatin regions.

Eider

In Northern Quebec, the common eider, Somateria mollissima, is hunted during the fall season when the birds gather close to the coast of Hudson Bay. But since the harvest surveys in this area do not distinguish between the different species of birds, data on consumption are unavailable. In Labrador, consumption of common eider and king eider,Somateria spectabilis, is between 10 to 18 g/pers/day. In the Arctic, the quantities of food oscillate between 6 to 20 g/pers/day in Baffin, is under 9 g/pers/day in Ellesmere and 5 g/pers/day in Keewatin.

viii ix

1.5.4 Fish

Arctic char

Arctic char, Salvelinus alpinus, is another important element of the native diet. In Northern Quebec, it is most abundant in the Ungava and Hudson Bays but is rarely seen in the James Bay area. This species represents more than half of the number of fish caught by the Inuit an equivalence of between 8 to 545 g/pers/day. The smaller catch of the Crees of Whapmagoostui, Chisasibi and Wemindji amounts to less than 8 g/pers/day. In Labrador, between 17 to 27 g/pers/day are eaten, while in Baffin, Ellesmere, Keewatin and Kitikmeot the quantities vary between 20 to 210 g/pers/day, 25 to 115 g/pers/day, 1 to 50 g/pers/day and 68 to 450 g/pers/day respectively.

Lake trout

In Northern Quebec, the lake trout, Salvelinus namaycush, has 2 distinct size ranges. The trout caught in the northern part by the Inuit are bigger than the specimen harvested by the Crees further south. Consequently, while the Crees and the Inuit catch about the same number of trout, the quantity of food represents less than 30 g/pers/day and 178 g/pers/day respectively. In the Keewatin region consumption ranges from 3 to 25 g/pers/day compared to 10 to 45 g/pers/day in the Kitikmeot region.

Lake whitefish

Lake whitefish, Coregonus clupeaformis, is the most popular species of whitefish. The Inuit of Northern Quebec eat between 10 to 65 g/pers/day, while the Crees consume less than 27 g/pers/day. In the Kitikmeot region consumption varies between 5 to 18 g/pers/day. In the Mackenzie Delta it represents a quarter of the domestic fisheries catch.

20

Rock cod

Rock cod, Gadus ogac, is found in the coastal waters from Alaska to Greenland and also enters the Hudson Bay waters. It also inhabits the waters off the Labrador Coast. In the latter region, the quantity eaten ranges from 10 to 15 g/pers/day Elsewhere, the catch is not very important.

Burbot

In the Mackenzie river valley of the Inuvik region, the burbot, Lota lota, is part of the native diet. The liver is considered a delicacy.

21

M M M R I

PART II

THE FOOD CHAIN

fcL

The ecological concept of the food chain accounts for the transfer and bioaccumulation of contaminants in living organisms. In its simplest form, it can be illustrated as herbivores feeding on plants and carnivores feeding on herbivores or on other carnivores. However, the trophic level occupied by an organism is not the only factor determining the concentration of contaminants. Other processes also come into play.

2 .1 Food Chains and Trophic Levels

A food chain is composed of different trophic levels. The number of trophic levels depends on the relationships between the various species. Each organism is part of a food chain because it is a consumer and in due time it will also be consumed. At the bottom of a food chain are the organisms who produce energy using nutrients and/or solar energy such as plants and phytoplankton. Above them are the consumers of those primary producers who, in turn, will be eaten by other predators. A top predator is a carnivorous species who has few or no predators.

This concept is generally employed in describing and analyzing the flow of biomass and metabolic energy throughout an ecosystem. For example, the quantity of energy metabolized at each level decreases when transferred to a superior trophic level. At the opposite, contaminants are concentrated as they go up the food chain, a process called biomagnification.

2 -2 Accumulation of Contaminants

2 .2 .1 Modes of Exposure

Although important, exposure through the food chain is not the only pathway through which toxic products enter organisms. The environment in which organisms live can also be a source of contaminants. The extent of exposure depends on the nature of the environment (water, air...), on the physiology of the organism (skin,

25

cellular systems), on the size of the animal surface exposed and on the chemical properties of the contaminants.

2 .2 .2 Properties of Contaminants

The affinity of contaminants for certain tissues is a function of their chemical nature. Even though certain similarities exist between compounds of the same family regarding their repartition in organisms, each compound reacts in a specific manner which is more or less well-known. In this study, two families of contaminants are examined: organochlorines and metals.

Synthesized by man, organochlorines are compounds which possess a high bioaccumulation potential. They are weakly soluble in water (hydrophobic) and chemically stable. Being lipophilic, they penetrate cellular membranes and concentrate in fatty tissues.

Metals occur naturally in the environment but their chemical structure, as well as their quantity and distribution, may be modified by industrial processes such as mining. The absorption of a metal by animal tissues depends mainly on the nature of the compound to which it binds. Some metals have an affinity for intracellular proteins and form metalloproteins which can then become integrated into metabolic systems. They also have a tendency to concentrate in certain tissues and organs.

Competition between contaminants can also affect their concentration in the various tissues. For example, similar contaminants can compete for receptors inside the tissues. The effect may be antagonistic (i.e. the effect response is inferior to the one expected when summing the effects of the individuals compounds) or synergic (i.e the effect response is superior to the one expected when summing the effects of the individual compounds). These processes have been little studied but must be kept in mind when interpreting data on contamination.

2.2 .3 Other Factors

The physiology of an organism varies with time, activity and the stage of its life cycle. Consequently, a number of factors will facilitate the accumulation or elimination

26

of contaminants. For example, during the reproduction period, physiological changes and modifications in the behavior can influence the uptake of contaminants. The seasons, the migration periods, the types of available prey and its area of activity are all important variables. Species, size, age, sex, metabolism and population density are other variables which can also influence the bioaccumulation potential of contaminants.

2.3 Northern Aquatic Food Chains

Northern aquatic food chains, which have man as top predator, are the main focus of this report. Since each species feeds on a variety of prey, depending on their availability, the diversity of diets is high. In order to better visualize a given food chain and to identify possible sources of contamination, we compiled a list of the alimentary habits of the fourteen species chosen as the most representative of the diet of native people.

2.3 .1 Prey Consumed by Northern Food Species

Polar bear

The diet of this important predator varies with the seasons. In winter, the polar bear feasts on ringed seals, bearded seals, harbour seals, young walrus and fish. It is partial to seal fat. Its summer diet includes stranded whales, lemmings, seabirds eggs, algae, marine invertebrates, berries and plants. The polar bear is one of the top predator of the Arctic.

Beluga

In the Arctic, the beluga feeds mainly on arctic cod and Greenland halibut. The Hudson Bay and St. Lawrence Estuary belugas also eat lance and capelin. Belugas also forage on arctic grayling, salmon, herring, cod, shrimp, marine worms and squid.

27

Narwhal

When feeding offshore, the menu of the narwhal includes squid and octopus. Closer to the coast, it also eats shrimp, arctic cod and Greenland halibut.

Ringed seal

This species mainly feeds on small planktonic crustaceans such as amphipods, mysids and decapods. It will not mind small arctic cod and sculpins.

Bearded seal

The diet of the bearded seal comprises invertebrates (shrimp, shellfish, bivalves and gastropods) and fish (sculpin, arctic cod, lance). They sometimes feed on crabs and marine worms. They are mainly benthic feeders.

Harp seal

Fish, such as capelin, herring, cod, halibut, flounder, rockfish and smelt make up

a good part of the diet of the Harp seal, as well as crustaceans, euphausiids, krill, decapods and shrimp. In addition, individuals living in the Arctic also feed on arctic cod.

Walrus

Its diet includes bivalves, whelks, sea cucumbers and marine worms. It sometimes gulps down small arctic cod and parts of seals; narwhals and belugas have also been found in its stomach.

Arctic char

Arctic char is an anadromous fish and has a carnivorous diet. Accordingly, its diet varies with its environment. In a marine environment it mainly eats invertebrates (amphipods and copepods) and fish (sculpins, Arctic char, lance and the fries of its

28

own species). In freshwater, it feeds on molluscs, aquatic insects, brook trout, rainbow smelts and sticklebacks.

Lake trout

Lake trout is predominantly piscivorous. But in addition to fish (ciscos, round whitefish, sticklebacks) they sometimes feed on benthic organisms, plankton and terrestrial insects.

Lake whitefish

This fish is mainly a benthic feeder. It eats molluscs, insect larvae, lake shrimp, snails and clams.

Rock cod

Capelin, arctic cod, small rock cod and Greenland halibut are the preferred preyof the rock cod . Its diet also includes invertebrates such as amphipods, shrimp, crabs, molluscs and worms.

Burbot The burbot is a voracious carnivore. Its diet is principally composed of fish such

as cisco, sculpin, whitefish, sticklebacks and trout-perch.

Canada goose

These migrating birds are exclusive herbivores. They eat grasses, seeds and small fruits. The Canada geese can be found along the seashore or close to fresh water during nidification.

Common eider

The common eider is found only in marine environments. It has a diet mainly centered on mussels although during breeding season its diet may include

21

amphipods, snails and herring eggs. Even though the common eider is considered a migrating species, certain populations winter in Hudson Bay and in Greenland.

2.4 Example of a Food Chain

Figure 2.1 illustrates in a simplistic wayt the complexity of a food chain in the aquatic environment of the Arctic. In the example, we chose the contaminant dieldrin to demonstrate the interactions between the various trophic levels of the food chain. The data come from many sources and sometimes the mean may have been calculated using data from different studies. When possible, a preference is given to the Baffin region.

At the bottom of the chain is snow which will eventually end up in the water. Concentrations in the snow and water are 0.75 and 3 ng/L, respectively. Only algae and zooplankton are included in the lower trophic levels of the figure but it should be kept in mind that any organism living in the same environment will be exposed to the contaminants.

The algae and zooplankton will be consumed by predators, invertebrates and fish, who in turn will be eaten by birds, marine mammals or humans. The higher the trophic level the greater the accumulation of dieldrin, especially in the beluga and the polar bear which have levels above 400 ng/g in their lipids. The only available data for man, who stands at the top of the food chain, are the concentrations measured in breast milk fat. The average level of 43 ng/g is lower than the one expected from a top predator, but many factors, such as the frequency of breast feeding and the consumption of traditional food, may influence the concentrations in women. Yet, it is obvious that the food chain plays an important role in the bioaccumulation of contaminants.

30

Figure 2.1 Biomagnification of dieldrin in the arctic aquatic food chain (wet weight) (1) McNeely & Gummer, 1984; (2) Gregor & Gummer, 1989; (3) Hargrave, 1988. (Other data are extracted from this report.)

3 1

PART III

ANIMAL CONTAMINATION

Numerous studies have looked at the contamination of the arctic fauna. In this section we review the research done on the different animal species and contaminants that we identified as being of concern to the native populations. This approach allows us to point out areas where data are lacking.

We proceed from the most to the least toxic contaminant, reviewing, for each of the 14 products, the information available on the 14 animal species that we chose as most representative of the native diet. We limit our analysis to three tissues: the blubber, because most organochlorines are lipophilic and because northern residents have a lipid-rich diet, the muscle, because it is eaten in large quantities, and the liver because contaminants tend to accumulate in this commonly eaten viscus.

3 .1 T C D D

TCDD or 2,3,7,8-tetrachlorodibenzo-p-dioxin is an organochlorine of the polychlorinated dioxin group. Known as dioxin, it is an extremely toxic chemical. It is a by-product in the manufacturing of several commercial compounds, among them chloro-phenoxy herbicides. It is also produced during the combustion of organic matter.

TCDD has been sampled in only three of the species under consideration: the ringed seal, the beluga and the polar bear. The lowest levels in the blubber were measured in the beluga from the Baffin, Keewatin and Inuvik regions (Table 3.1). In fact, the levels were under the detection limit of 2 ng/kg for pools of 8, 19 and 5 individuals, respectively. All the data come from a single study (Norstrom et al., 1990).

Analyses were conducted on ringed seal from the same regions, as well as from the Kitikmeot region. Mean levels in the blubber range from 2.5 to 27.1 ng/kg, the highest concentrations were observed in the Kitikmeot and Baffin regions.

In the polar bear, the mean levels in the blubber vary from 2 to 18 ng/kg. Analyses were also done on liver, yielding results of 2 and 12.5 ng/kg for the Inuvik and Kitikmeot regions, respectively.

35

TCDD concentrations in the blubber of polar bears seem to follow a geographical trend (Figure 3.1). The levels increase from east to west. The same trend is not observed in the ringed seal, but it should be kept in mind that the result from Inuvik is taken from a single animal.

3 . 2 Aldrin and Dieldrin

Aldrin and dieldrin are organochlorinated insecticides with neurotoxic properties. These two insecticides have not been manufactured in the United States since 1975 and in Canada since 1990. In the latter case however, their use has been permitted for five years after the ban to allow stock depletion (Agriculture Canada, 1991). Aldrin is used in the control of beetles and termites while dieldrin is used in agriculture to treat seeds and soil, and to control disease vectors such as the mosquito and the tsetse fly. The two insecticides are very close chemically: dieldrin is the more stable epoxy form of aldrin and it is under this form that aldrin accumulates in tissues.

The degradation of aldrin into dieldrin occurs both in the environment and within animals.

3 .2 .1 Aldrin

Aldrin has been measured in three species of mammals and one of fish. The

data on mammals cover only the Baffin region (Table 3.2). In the ringed seal, the mean levels in the blubber, liver and muscle are under 0.12, 0.07 and 0.02 ng/g respectively. In the bearded seal, the mean concentrations are under 0.03 and 0.003 ng/g in the blubber and muscle. As for the walrus, the only available value is under 0.06 ng/g of aldrin in the blubber.

Analyses were conducted on the arctic char in the regions of Baffin, Keewatin, Inuvik and Kitikmeot (Table 3.3). In the muscles, the mean levels vary between <0.004 to 1.2 ng/g. Data on other tissues are available for the Baffin region, and the mean concentrations in the blubber and liver are under 0.01 ng/g.

The low concentrations observed in these few cases could be due to the

37

39

40

unstable nature of this chemical and may reflect only short term exposure Dieldrin

which is very stable, represents the principal residue found in animals exposed to aldrin.

3.2 .2 Dieldrin

3 .2 .2 .1 Mammals

This organochlorine has been widely studied. Of all the mammals studied in

this report, only the harp seal has not been sampled. Figure 3.2 illustrates the mean levels of dieldrin in the blubber of the various species for most of the regions. The least contaminated species are the ringed seal and the bearded seal, with mean concentrations under 160 ng/g (Table 3.4). The mean levels in the liver and muscle are also, at less than 3.5 ng/g, below the values obtained from the other sampled species. The fact that these seals mostly consume invertebrates may explain these differences.

The walrus also feeds on invertebrates, however, the mean levels measured in )ts muscle (7.4 ng/g) and blubber (280 ng/g) are comparable to the ones observed in the beluga, polar bear and narwhal. It should be kept in mind that data on dieldrin contamination for the walrus are sparse and limited to the Baffin region, and that its diet may not be restricted to invertebrates, as remains of marine mammals have been found in its stomach.

The beluga, the polar bear and, to a lesser extent, the narwhal have been studied more intensively. Mean concentrations in the fatty tissues range from 199 to 1007 ng/g for the beluga, from 190 to 910 ng/g for the polar bear and from 370 to 417 ng/g for the narwhal. The highest mean level in the muscle, 22 ng/g, has been found in the narwhal of the Kitikmeot region while the highest mean concentrations in the liver, 230 to 833 ng/g, have been found in the polar bear. In two regions, Inuvik and Baffin' the mean levels in the liver of the polar bear were higher than the mean levels in the blubber of the same species (Figure 3.3).

There does not seem to be any geographical trend in dieldrin contamination in the beluga, ringed seal or polar bear (Figure 3.4). It should be noted, however, that the

21

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Figure 3.2 Mean levels of dieldrin in the fatty tissues of mammals (ng/g, wet weight).

42 43

Ellesmere Baffin Kitikmeot Inuvik Keewatin

Figure 3.3 Mean levels of dieldrin in the liver and lipids of the polar bear (ng/g, wet weight).

44

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45

concentrations of dieldrin in the lipids of the polar bear are particularly high in the Keewatin region. As will be the case for other organochlorines, certain species are often more contaminated in the Keewatin region than in the other regions.

3.2 .2 .2 Fish

Data on fish are sparse (Table 3.5). The most sampled species is the arctic char. The mean dieldrin levels in the muscle vary between 1.0 to 2.4 ng/g, except in the Ellesmere region where the mean levels attain 13 ng/g. This result stands out in Figure 3.5 where the data are summarized. The lack of data makes any comparison difficult.

In the lipids and liver of the arctic char, the only available data are 12 and 13 ng/g respectively.

3.2 .2 .3 Waterfowl

The only waterfowl species sampled is the common eider in the Kitikmeot and Baffin regions (Table 3.6). In the muscle, the mean levels for these regions are 20 ng/g and 4.5 ng/g respectively, As for the liver and the lipids, the only information comes from samples from Baffin. The mean concentration in the liver is 4.7 ng/g, while the mean level in the lipids is 24 ng/g, only slightly greater than the one in the muscle. The difference between the two tissues is unusually small. In general, the levels are several orders of magnitude greater in the fatty tissues than in the muscle.

3 .3 Chlordane

Chlordane is an organochlorinated insecticide and, like aldrin and dieldrin, is a neurotoxicant. According to Agriculture Canada, its registration was cancelled in December 1990, but its sale is permitted until December 1995. The concentrations are expressed as a summation (X) of a number of closely related compounds: oxychlordane, cis-chlordane and trans-chlordane. Certain authors also include other compounds like heptachlor epoxyde.

46 21

Figure 3.5 Mean levels of dieldrin in the muscle of fish species (ng/g, wet weight)

48

3.3.1 Mammals

Chlordane has been widely studied in the arctic fauna, especially the beluga, polar bear and ringed seal (Table 3.7). Figure 3.6 illustrates the levels in the fatty tissues of the various mammal species by region.

The most contaminated species are the polar bear and the beluga, with mean levels ranging from 2280 to 6990 ng/g in the lipids of the bear and from 1060 to 2586 ng/g in the blubber of the beluga. The sparse data on the walrus (1385 ng/g) and narwhal (685 and 1715 ng/g) blubber also point to high levels.

As was the case with dieldrin, the mean levels of chlordane in the liver of the polar bear are in the same order of magnitude as the ones in the lipids, and noticeably higher than the mean liver concentrations in the other species. Once again, the mean levels in the liver exceed the ones in the lipids for the regions of Baffin and Inuvik (Figure 3.7).

In the muscle, the mean levels range from a low of 9.3 ng/g in the beluga to a high of 63 ng/g in the narwhal. The data on the polar bear and walrus fall between these values.

The bearded seal and the ringed seal feed mostly on invertebrates and, as expected, are less contaminated than other mammals. The mean levels in the blubber of the ringed seal vary between 292 to 1398 ng/g compared to 59 to 316 ng/g in the bearded seal.

In Figure 3.8, the mean concentrations of chlordane in the fatty tissues of the ringed seal, beluga and polar bear are graphed for each region. As it happened with dieldrin, the highest levels in the polar bear and ringed seal were obtained in the Keewatin region. No spatial trend could be identified.

50 51

Figure 3.6 Mean levels of total chlordane in the fatty tissues of mammals (ng/g, wet weight)

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3.3.2 Fish

Relatively little information is available on chlordane contamination in fish (Table 3.8). The mean levels in the muscle range from 0.83 ng/g in the burbot to 91 ng/g in the arctic char. Both species are carnivorous and are thus at the same level in the food chain. The large differences in the degrees of contamination could be due to the sparsity of data and to geographical variations.

Figure 3.9 illustrates the differences in the chlordane levels in the muscle of four fish species. The concentrations measured in the Arctic char of the Ellesmere region stand out. The data come from Amituk Lake, a sampling site which, in many instances, comes out as being more contaminated than other sites.

3.3.3 Waterfowl

The common eider is the only species for which data are available, albeit very few animals have been sampled (Table 3.9). The mean levels measured in the muscles are similar for the two sites in Kitikmeot and Baffin, 12.0 and 10.2 ng/g respectively. As expected, because of the lipophilic nature of organochlorines, the mean concentrations in the lipids are higher at 100 ng/g. The level in the fat could also be affected by the physiological state of the bird whose fat reserves were low in June, after migration and reproduction.

3 .4 Lindane

Lindane, an organochlorinated insecticide, is also known as the gamma isomer

of hexachlorocyclohexane (g-HCH) or as the gamma isomer of benzene hexachloride (g-BHC). This insecticide is used in treating domestic animals for fleas and in protecting seeds and plants against insect pests. It is also used in the treatment of scabies.

Data on lindane contamination is next to nonexistent. The only information available relates to the concentration in the muscle of arctic char from the Kitikmeot

21

Figure 3.9 Mean levels of total chlordane in the muscle of fish species (ng/g, wet weight)

57

region (Canada, DFO, 1990). The mean level for a sample of 10 individuals is below 1 ng/g. The transfer of lindane through the trophic chain of the Arctic remains unknown.

3.5 Endrin

Endrin is an organochlorinated insecticide used in agriculture. Since December 1990, Canada has joined other countries which have banned endrin. Its sale, however, is allowed for five years following that date until stock depletion.

Endrin has been studied in some species of mammals and fish, but not in the waterfowl.

3.5 .1 Mammals

Some information is available from the Baffin region but is limited to three species: the ringed seal, the bearded seal and the walrus (Table 3.10). The most contaminated blubber, at 6.4 ng/g, belongs to the walrus, but this value represents only one individual. The mean levels in the ringed and bearded seal are <1.9 ng/g and 0.93 ng/g respectively. The only data on the contamination of the liver is from the ringed seal and is less than 0.20 ng/g.

3.5 .2 Fish

Arctic char is the only sampled species of fish (Table 3.11). The samples were taken in the Keewatin, Inuvik and Kitikmeot regions and were analyzed by the inspection branch of the Department of Fisheries and Oceans Canada (Canada, DFO, 1990). The mean levels of 1 ng/g measured in the samples represent the DFO's detection limit. In another study analyzing samples from the Baffin region, the mean levels in the liver were 2.5 ng/g in the liver, 2.1 ng/g in the lipids and 0.3 ng/g in the muscle.

It is impossible to discern any trends from such a sparse data set.

59

60 61

3.6 Mercury

Mercury is a metal naturally present in the environment, and it can also originate from industrial sources. Two forms exist, an organic form, such as methylmercury, and an inorganic form. The latter can be converted into methylmercury by bacterial action. It is mainly the organic form which bioaccumulates through the food chain in living organisms. In the following section, mercury refers to total mercury: the summation of inorganic and organic form. The contamination by methylmercury will be discussed in a later section.

3.6.1 Mercury

3.6.1.1 Mammals

One study, done by Dietz et at. (1990) in Greenland, covers all the mammals we are interested in, except for the walrus (Table 3.12). The liver and the muscle were analyzed and the results are presented in Figure 3.10. The higher levels found in the liver illustrate the importance of that organ in accumulating mercury. In Greenland, the most contaminated species was the ringed seal with 21.4 ng/g of mercury in the liver, followed by the bearded seal with 13.4 ng/g and the polar bear with 11.5 ng/g.

These results, however, are expressed on a wet weight basis, while the data from the other regions are expressed on a dry weight basis. Conversion factors are available for the beluga and the narwhal, and since they are fairly similar (the wet weight being approximately four times the dry weight), for comparison sake we used a factor of four to convert the results for the polar bear of Greenland into dry weights. The converted mean values for the liver and muscle are 9.75 and 2.31 ng/g, respectively, in the beluga and 46.0 and 0.36 ng/g in the polar bear. We can then compare all the regions with respect to the levels in the liver (Figure 3.11).

The data for the polar bear indicate an increase in contamination from east to west as well as south to north. For the beluga, the trend seems to be reverse with a decrease in contamination from south to north, if we exclude the Inuvik region.

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3.6.1 .2 Fish

Most of the research done on mercury contamination in fish was performed on samples from the Hudson and Ungava regions. These studies were part of an environmental monitoring program for the hydroelectric projects built or to be built in those regions. In Table 3.13, it is specified when the data come from areas modified by hydroelectric projects (dammed areas) as opposed to natural areas, where there has never been hydroelectric installations. CLG denotes the Complexe La Grande , while CF stands for Churchill Falls.

The main species sampled in the dammed and natural areas of the Hudson and Ungava regions are the lake trout, the lake whitefish and the burbot. Analyses were done on the muscle and are expressed on a wet weight basis. The highest levels are found in the lake trout which has a piscivorous diet. These levels are superior to those measured in the lake whitefish, a bottom feeder.

Concentrations are superior in the fish found in the waters affected by the dams as mercury became more bioavailable from the flooding of new soil surfaces. In these regions, the levels of mercury in the sediments are naturally high but, if left undisturbed, the mercury will be released very slowly in the water through erosion. The flooding of large areas of land, however, accelerates this process (Pérusse,1991).

According to certain studies (as Brouard et al., 1990) mercury levels in the fish from reservoirs increase for a period of five to ten years after flooding, before decreasing (resoption phenomenon). A return to natural mercury levels in fish can take between 20 to 30 years, depending on the species, age and exploitation conditions of the reservoir. For example, the Smallwood reservoir (CF) was created in 1972, seven years before the first reservoirs of the Complexe La Grande in 1979, and the mercury levels are lower in the former than in the latter.

Levels in fish from areas affected by the Complexe La Grande, be they in the Hudson or Ungava regions, are fairly similar. In Figure 3.12, mean levels in the three most studied species, the lake trout, lake whitefish and burbot, are presented for both the dammed affected and natural areas. In all cases, the concentrations are lower in the undisturbed areas. In dammed areas, the mean levels range from 1290 to 1390

60 66

60

ng/g in lake trout, 189 to 500 ng/g in lake whitefish and 487 to 1196 ng/g in burbot. The mean level observed in lake whitefish of Churchill Falls (189 ng/g) is comparable to the mean concentration measured in natural areas (187 ng/g) indicating a possible return to the original conditions.

Data on burbot point to a lower level of mercury within the dammed areas, but the sample size is too small to draw any conclusions. Variations in levels according to the age of the fish may explain this discrepancy in the data. Such a relationship has been demonstrated for many species (Brouard etal., 1990).

Other high levels have also been observed in other regions, notably in the lake trout of the Fort Smith region (480 ng/g) and the burbot of the Inuvik region (268 ng/g).

3.6 .1 .3 Waterfowl

The only information available relates to the common eider of Greenland (Table 3.14). The levels measured are 150 ng/g in the muscle and 820 ng/g in the liver. It would be interesting to know the levels in the molluscs of the region since they constitute their main diet.

3.6 .2 Methylmercury

Generally, only the value for total mercury is given, but in one study both the levels of total and organic mercury are presented (Dietz et al., 1990). As the analyses were done on animal tissues, we assume that the organic mercury is methylmercury.

Data are presented in Tables 3.15 and 3.16 and cover seven species of mammals and waterfowl from Greenland. In all instances except one, the narwhal, the levels in the liver are higher than in the muscle (Figure 3.13). When total mercury levels are compared to methylmercury levels, we observe that in the muscle methylmercury accounts for the majority of total mercury (Tables 3.12 and 3.15). The levels of methylmercury in the liver of mammals represent, however, only a small fraction of total mercury. Consequently, most of the mercury found in the liver is in inorganic form.

69

74 71

60 72

Harp seal

Bearded seal

Ringed seal

"i i 1 1 1 r 100 200 300 400 500 600 700 800

Mean levels of methylmercury, ng/g

Figure 3.13 Mean levels of methylmercury in the tissues of mammals from Greenland (wet weight).

3.7 DDT

DDT, or dichlorodiphenyltrichloroethane, is an organochiorinated insecticide which was utilized to control parasites and other insect pests. It has also been used as a prophylaxis against cholera by direct application to the skin. Its low cost of production and its wide uses made DDT a very popular insecticide from the 1940's to the beginning of the 1970's. At that time, a movement to restrict the use of the insecticide because of its effects on the reproduction of predatory birds was launched in North America. In Canada, restrictions were imposed at the beginning of the 70s but certain products containing DDT were allowed until 1985. Its use and sale were stopped completely in December 1990. DDT, however, is still employed in parts of the world, despite pressures to ban it.

Like all organochlorines, DDT is lipophilic. It is commercially available in three formulas which differ from one another by the position of chlorine on the benzene ring (o,o'; o,p; p,p'-DDT). Two metabolites of DDT, DDE and DDD are also toxic and bioaccumulate in tissues. DDE is the most commonly found metabolite since it has a long half-life. In most studies, the data are presented as a summation of DDT and its metabolites, 2 DDT or total DDT, an approach we also adopted in this report.

3.7.1 Mammals

Data on DDT contamination is available for all the mammal species, except the harp seal, as illustrated in Figure 3.14. The mean level in the blubber of the beluga is higher in Greenland, 5470 ng/g, than in the Canadian Arctic, where it ranges from 1990 to 3920 ng/g (Table 3.17). In the narwhal from the Kitikmeot and Baffin regions the mean levels reported are 2130 and 5060 ng/g respectively, but the result from Kitikmeot represents only one individual. These two fairly similar species in terms of their trophic level, are noticeably more contaminated than the other mammals including the polar bear. '

In the polar bear, the mean concentrations vary between 140 to 310 ng/g in the hP,ds, w,th the exception of the polar bears from the Keewatin region which are heavi.y contammated at 1070 ng/g. The mean level in the liver is also elevated at 783 n^g !

74

% ®

Figure 3.14 Mean levels of total DDT in the fatty tissues of mammals (wet weight)

75

100

Data from this region stand out in Figure 3.15 where they are compared with those from the other regions. It should also be noted that in the samples from the Inuvik region, the mean levels of total DDT in the liver are higher than in the lipids.

As was the case for the other organochlorines, mean levels in the lipids of polar bears are highest in the Keewatin region (Figure 3.16). As for the beluga, the mean concentrations seem to increase from south to north in the eastern regions of Hudson, Baffin and Greenland. They also show an increasing trend from west to east, as one goes from Inuvik, to Kitikmeot, Baffin and Greenland.

Paradoxically, the blubber of the ringed seal is two to three times more contaminated than the lipids of the polar bear, its main predator. The mean levels range from 430 to 660 ng/g, with one outlier, 2180 ng/g, which was measured on a specimen from the Keewatin region.

Levels are much lower in the muscle and liver but in one instance, that of the ringed seal from Baffin, the mean concentration is higher in the muscle than in the liver.

The bearded seal and walrus have been little studied. Mean levels in the blubber of the bearded seal vary between 80 to 570 ng/g while the only available result for the walrus indicates a mean concentration of 960 ng/g.

3.7.2 Fish

Relatively few studies have looked at DDT contamination in fish (Table 3.18). The most studied species is the arctic char. In most instances, the mean level in the muscle oscillates around 3.0 ng/g, except in the Ellesmere region where it reaches 69 ng/g. As was the case with dieldrin and chlordane, the samples which come from Amituk Lake near Resolute Bay have markedly higher concentrations.

In Figure 3.17, data on the arctic char are compared to the little information available on other species. One other result stands out, it is the mean level in the muscle of the lake trout from the Keewatin region (33 ng/g).

77

Keewatin Inuvik Kitikmeot Baffin Ellesmere

Figure 3.15 Mean levels of total DDT in the tissues of the polar bear (wet weight).

102 79

100

Mean levels levels of total DDT weight)

in the muscle of fish (wet

81

Data on liver contamination are even more scarce. In burbot the mean level is 43 ng/g, while one analysis on the arctic char indicates a level of 30 ng/g.

3.7 .3 Waterfowl

Data on birds are even more sparse (Table 3.19). One study on the common eider by Thomas (1990) indicates a level of 23 ng/g in the muscle of only one individual from the Baffin region, while a slightly larger sample from the Kitikmeot region reveals a mean level of 3.1 ng/g.

The mean level in the lipids, 60 ng/g, is in keeping with the high lipophilic nature of the contaminant.

3-8 Heptachlor / Heptachlor epoxide

Heptachlor is an organochlorinated insecticide that was once widely used to control termites. According to Agriculture Canada, registration of heptachlor was cancelled in December 1985 and its sale, as well as its use, stopped five years later, in December 1990.

Heptachlor can be oxidated into heptachlor epoxide. This metabolite is more persistent in the environment than heptachlor, its half-life being in the order of 14

years, as opposed to 2 years. In addition, the epoxide form is not easily photolyzed oxydized or hydrolyzed (ATSDR, 1989) and because it is lipophilic, the epoxide form accumulates in fatty tissues.

3.8 .1 Heptachlor

Only three species of marine mammals from the Baffin region have been sampled so far (Tableau 3.20). The mean levels in the blubber of the ringed seal bearded seal and walrus are, respectively, less than 0.18, 0.05 and 0.1 ng/g The last two values were obtained from one individual which rules out any interpretation of the data.

82 83

100 84

As for fish, arctic char is the only species for which we have information (Table 3.21). All the levels are low, close to the detection limit. This is not surprising given the unstable nature of heptachlor.

3.8 .2 Heptachlor epoxide

As was the case for heptachlor, little information is available for its epoxide form. It should be noted, however, that the mean levels of heptachlor epoxide are several orders of magnitude higher than the mean levels of heptachlor.

3.8.2.1 Mammals

The mean level in the blubber of ringed seal from the Baffin region is 52 ng/g, while it is 32 ng/g in the bearded seal and 27 ng/g in the walrus (Table 3.22). The only data on liver contamination indicate a mean concentration of 2.06 ng/g in the ringed seal. In the muscle, the mean levels vary around 1.0 ng/g.

3.8 .2 .2 Fish

Once again, the arctic char is the main focus of the research (Table 3.23). The most contaminated tissue is the liver with a level of 5.2 ng/g, but this value is the result of only one analysis. Mean levels in the lipids are fairly similar, 4.3 ng/g, but the sample size is still small (n=2). More information is available for the muscle, and the results, which fluctuate around 1.0 ng/g, are consistent across the four regions sampled.

As for the rock cod, the mean levels of heptachlor epoxide in the whole animal are less than 0.05 ng/g in the samples from the Kitikmeot and Baffin regions.

3.9 HCB

HCB or hexachlorobenzene is a fungicide used, among other things, to treat seeds. It is also an organochlorinated pesticide and like all the other chemicals of this

100 86

JH iMÈ

group, is lipophilic. In Canada, HCB is no longer manufactured since December 1990, but the remaining stocks can be bought until the end of 1995.

3.9 .1 Mammals

A fair number of studies have looked at HCB contamination, and the most studied species are the beluga, the polar bear and the ringed seal (Table 3.24).

The highest levels are found in the beluga which has been sampled in six regions. Mean concentrations in the blubber vary between 218 to 570 ng/g. In Figure 3.18, the levels measured in the beluga are compared to the ones measured in the polar bear and the ringed seal. It should be noted that the levels in the Kitikmeot region are based on one analysis each for the beluga and the polar bear.

Keewatin is once again the region where the highest level of HCB was measured in the fatty tissues of the polar bear. As shown in Figure 3.19, the levels in that mammal seem to decrease from south to north. The sample sizes are small but, as specified in the annex, in many instances the analyses were done on a pool of six to ten individuals.

The concentrations in the fatty tissues of two species of similar trophic level, the ringed seal and bearded seal, are lower than in the beluga and polar bear. Means range from 12 to 13.4 ng/g in the bearded seal and from 14.3 to 21.4 ng/g in the ringed seal.

The only result available for the walrus indicates a surprisingly low level of contamination; blubber concentration is 0.14 ng/g (Table 3.24).

As for the muscle, the highest mean level is observed in the beluga from the Hudson region. In the Baffin and Kitikmeot regions, the levels are under 1 ng/g, but the data are based on only one analysis in each case.

information on the HCB contamination in the liver is mostly available for the polar bear (Figure 3.20). In the ringed and bearded seals, levels are noticeably lower than in the polar bear and the beluga, for which there is only one result

89

90

100

m

93

available. As was the case with the other tissues, these two top predators are more contaminated than seals.

3 .9 .2 Fish

HCB contamination in fish is not well documented. The only species for which there is data for all three tissues in the same region, is the arctic char (Table 3.25). mean levels in the muscle, lipids and liver are 2.6, 11.5 and 9 ng/g respectively. The value of 11.5 ng/g in the lipids is the mean of two samples, one from Arctic Bay (22 ng/g) and the other from Clyde River (1 ng/g). It is impossible to conclude from such a limited data set whether the difference is age related or site related.

Results from the other regions of Kitikmeot, Inuvik and Keewatin vary between 1 to 1.6 ng/g in muscle, the value of 1 ng/g being the detection limit of the Department of Fisheries and Oceans.

Analyses done on the whole rock cod indicate mean levels of 0.31 and 0.82 ng/g for the Kitikmeot and Baffin regions respectively.

There are also results on the burbot but the levels measured in the liver are expressed as geometric means. The values of 34 ng/g from Fort Smith and of 38 ng/g from the Inuvik region are estimates of geometric means. These data are hardly comparable with arithmetic means but they are still fairly high. Those samples come from water systems affected by human activities: the Great Slave Lake and the Mackenzie River.

3 .9 .3 Waterfowl

To date, no analysis has been done on Canada geese, only common eiders have been sampled for HCB contamination (Table 3.26).

Mean level in the lipids of eiders from the Kitikmeot region is 32 ng/g. The mean concentrations in the muscle and liver are much lower at 0.6 and 0.4 ng/g respectively. Another sample from the Baffin region indicates a level of 10 ng/g in the muscle, however only one specimen has been analyzed. It should be noted that the sample

100 94

100 96

was taken in Arctic Bay and that it was a young individual (Annex, Table 107).

All the samples were taken in June, at a time when the percentage of fat is low due to the energy expended during migration and reproduction. The physiological state of the birds could thus affect the concentration of the contaminant in the tissues.

3.10 Cadmium

Cadmium is a metal naturally found in the environment. It is also generated through industrial activities such as zinc, lead or copper smelting, electrolysis, the manufacture of pigments for paints and plastics and the production of batteries. According to the Agency for Toxic Substances and Diseases Registry, the combustion of fossil fuels and incineration of municipal wastes are the main sources of cadmium (ATSDR, 1989).

3 .10 .1 Mammals

Data on cadmium contamination in mammals are presented under a variety of forms, making comparisons difficult. In addition to the traditional arithmetic mean, geometric means and medians are also given. The results are either expressed on a dry weight or wet weight basis.

For the beluga and the narwhal, the values are available on a wet weight basis, but were converted into a dry weight basis using the conversion factors given in Wagemann et ai (1991; 1983). The following results for the mammals are presented on a dry weight basis.

The liver and muscle of the beluga were sampled in six regions (Table 3.27). Mean levels range from 8.5 to 25.0 |j.g/g (dry weight) in the liver, with the highest value in the Keewatin region. In the muscle, the mean concentrations range between 0.07 and 0.65 jag/g. As shown in Figure 3.21, the highest levels are found in the eastern part of the Arctic, around Baffin Island and Hudson Bay.

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The concentrations in the liver of the polar bear are lower than in the beluga with means between 1.22 to 3.85 ng/g (dry weight) depending on the region. Although the range is small, the polar bear also seems slightly more contaminated in the eastern part of the Arctic (Figure 3.21).

The most contaminated mammal seems to be the narwhal, but the one result from Baffin (171.2 ng/g, dry weight) comes from one individual while the data from Greenland represent medians not means. The median levels in the latter are 74.3 and 1.4 |ig/g (dry weight) in the liver and muscle respectively.

As for the ringed seal, the only available arithmetic means are for the liver (23.3 ng/g, dry weight) and muscle (0.31 ng/g, dry weight) from the Baffin region. They are similar to the levels observed in the beluga from the same region. The other data from the Kitikmeot and Greenland regions are geometric means and range from 7.3 to 18.2 ng/g (dry weight) in the liver and from 0.13 to 1.02 ng/g (dry weight) in the muscle. Only one value is available for the blubber in the Kitikmeot region and is low at 0.03 ng/g (wet weight).

3 .10 .2 Fish

Only a few scattered data have been found on cadmium contamination in fish (Table 3.28). The levels are under the detection limit of 50 ng/g (wet weight) in the muscle of lake whitefish and in the muscle and liver of rock cod.

As for the burbot, the minimum and maximum levels measured in the liver are <100 and 400 ng/g in the Fort Smith region, and <100 and 300 ng/g (wet weight) in the Inuvik region.

3.10 .3 Waterfowl

The only dataset comes from Greenland (Table 3.29). The mean level in the liver of 2600 ng/g (wet weight) and of 160 ng/g (wet weight) in the muscle are fairly high and the standard deviation is large which indicates a lot of variability in the results.

100 101

102

3.11 PCB

PCBs, polychlorinated biphenyls, are important lipophilic contaminants due to their high stability and persistence in the environment. These organochlorines have between 12 and 68% of chlorine and, in general, the greater the proportion of chlorine, the more persistant the chemical. They were used in electrical transformers because of their insulating properties. Being non-flammable, they were also utilized in the manufacturing of various products. Since the end of the seventies, it has been gradually banned in a number of countries, including Canada.

The results are presented as a summation (X) of the various PCB congeners or as standard PCB mixture such as Aroclor 1260 and Aroclor 1248. The data for Aroclor 1260 are presented separately.

3.11 .1 I PCB

3.11.1 .1 Mammals

PCB contamination in mammals is well documented (Table 3.30). The most contaminated species of mammal is the polar bear, a top predator. Mean levels of total PCB in its lipids vary between 3400 to 8070 ng/g, the maximum value being from the Keewatin region. The number of samples from the Keewatin, Inuvik and Kitikmeot regions seems small, n=2 or 3, but each analysis represents a pool of 6 to 10 individuals (Annex, Table 63).

The only data on liver contamination come from the Inuvik and Kitikmeot regions. The mean levels are 750 and 646 ng/g respectively. In the muscle, the only information comes from samples taken in the Baffin region and the mean concentration is 97 ng/g.

A wide range of data is available for the beluga. The contamination in the blubber is highest in Greenland, with a mean level of 4961 ng/g. With the exception of one sample from the Kitikmeot region at 4708 ng/g, the mean levels in the other

103

102

regions range from 2000 to 2900 ng/g. The means are 304 ng/g in the liver and 43 and 70 ng/g in the muscle.

In Figure 3.22, the mean levels in the polar bear are compared to the ones in the beluga and the ringed seal. The highest levels in the polar bear and the ringed seal, one of its prey, were measured in the Keewatin region. There seems to be a slight tendency for the polar bear to be less contaminated in the eastern region of Baffin as opposed to the Kitikmeot and Inuvik regions. No spatial trend can be discerned for the beluga and the ringed seal.

Less data are available for the narwhal, but it appears to be more contaminated than the beluga. In the blubber, the level from one individual from Kitikmeot is 3337 ng/g while a larger sample from the Baffin region indicates a mean level of 4392 ng/g. The only result for the muscle is 240 ng/g.

Another limited set of data indicates a mean level of 2291 ng/g in the blubber of walrus from the Baffin region. In the muscle, the mean concentration is 62 ng/g.

The levels in the two species of seals are lower. Mean levels in the blubber of the ringed seal range from 479 to 1561 ng/g. In other tissues, the mean concentrations vary between 5.5 to 14.0 ng/g in the liver, and 2.0 to 32.8 ng/g in the muscle.

As for the bearded seal, total PCB levels are available for only three regions. In the Hudson region, the mean level in the blubber is relatively low at 73 ng/g, while the mean concentrations in the Baffin and Kitikmeot regions reach 610 and 1230 ng/g, respectively. In the liver, the levels are 30 and 42 ng/g, while in the muscle the mean concentrations range from 3.7 to 12.2 ng/g in the Kitikmeot and Baffin regions.

Data are illustrated in Figure 3.23.

3.11.1 .2 Fish

Data on the arctic char are available for five regions (Table 3.31). The mean concentrations vary between 3.4 to 135 ng/g in three regions, while the value of 1 ng/g

105

102

oi 9000 \ 8000 $ 7000

% 6000 o 5000 •S 4000 £ 3000 | 2000

f e.0SV

N N ^

s > 0 >

> s ^ % % % % % ^

Figure 3.23 Mean levels of total PCB in the fatty tissues of mammals (wet weight).

107

102

reported for the Keewatin and Inuvik regions represents the detection limit of the Department of Fisheries and Oceans inspection branch. Once again, the high level observed in the Ellesmere region belongs to samples taken at Amituk Lake. In the Baffin region, the levels are 30 ng/g in the lipids and 24 ng/g in the liver.

For the lake trout, the mean levels in the muscle are 11.3 and 49 ng/g for the Inuvik and Keewatin respectively, while analyses done on whole animals from Ungava indicate a mean concentration of 42 ng/g.

Lake whitefish from the Fort Smith region have a mean level of 14.6 ng/g in their muscle. Whole rock cod is less contaminated at 3.2 and 3.3 ng/g, but samples taken from the muscles, and expressed on a lipid weight basis, indicate mean concentrations of 221 and 356 ng/g. The analyses for this species were done on a pool of specimens.

In the burbot, the mean levels are 21 ng/g in the muscle and 82 ng/g in the liver. According to Muir, Rosenberg and Ford (1989), the percentage of lipids in the burbot is 20 to 50% higher in the liver than in the muscle. Given the affinity of PCB to lipids, it is not surprising to find higher levels in the liver than in the muscle. Other results regarding the PCB contamination in the liver are available but they are expressed as geometric means. They indicate mean levels of 333 and 557 ng/g in the Inuvik and Fort Smith regions respectively.

3.11.1 .3 Waterfowl

Only the common eider in the Kitikmeot and Baffin regions has been examined for PCB contamination (Table 3.32). The level in the muscle of a single eider from the Baffin region is relatively high at 476 ng/g. The mean concentration in the muscle of birds from the Kitikmeot region is much lower at 10.5 ng/g. The mean levels in the lipids are 90 ng/g while the only value for the liver is 7.3 ng/g.

3 .11 .2 Aroclor 1260

In a study by Norstrom et al. (1985), PCB data are expressed as equivalent concentrations of the commercial mixture Aroclor 1260. Mean levels in the liver of the

109

100 110

polar bear range from 1220 to 2070 ng/g, with the highest value coming from the Keewatin region (Table 3.33).

3 .12 Lead

Lead is a heavy metal toxic to living organisms. It is naturally found in the environment, but is also generated by industrial activities and the incineration of wastes containing this element.

Information regarding lead contamination comes from two sources (Table 3.34). In the beluga, mean levels range from 34 to 800 ng/g (dry weight) in the liver. Once again, the belugas from the Keewatin region are the most contaminated. In the muscle, mean concentrations vary between 23 to 30 ng/g (dry weight), with one exception: the mean from the Hudson region is 187 ng/g (dry weight). As seen in Figure 3.24, levels in the Hudson and Keewatin regions dominate the results.

In the ringed seals from the Baffin region, mean levels in the muscle and the liver are 40 and 80 ng/g, respectively. Contrary to expectations, this species is more contaminated than the beluga from the same region, even though the latter is higher up in the food chain.

3.13 Methoxychlor

Methoxyclor is an organochlorinated insecticide. It was first used as a replacement for DDT, as it is less toxic than the banned insecticide. It can be found in a number of insecticide formulations to control mosquitoes and black flies. It is also used on garden plants.

The only data come from the inspection branch of the Department of Fisheries and Oceans. The only sampled species is the arctic char from the Keewatin, Inuvik and Kitikmeot regions. All the levels, for samples of 12, 6 and 25 pools of 5 individuals, respectively, are below the detection limit of 1 ng/g.

100 113

900

Ê? 700

Hudson Keewatin Inuvik Baffin Eliesmere

Figure 3.24 Mean levels of lead in the tissues of beluga (dry weight).

114

PART IV

HUMAN CONTAMINATION

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fe...

Humans are an integral part of the arctic food chain, and the more traditional the life-style, the greater the risk of being exposed to contaminants present in northern food species. In this section, we review the extent of our knowledge of human contamination. The location of the various native settlements mentioned in this section, is illustrated in Figure 4.1.

4.1 Contaminants

4.1.1 Heavy metals

4 .1 .1 .1 Mercury

In Canada, people who consume an important quantity of fish and marine mammals are at risk of accumulating mercury. When diet is the main source of contamination, organic mercury, as methylmercury, accounts for most of the total mercury. Some researchers measure only total mercury while others also measure inorganic mercury to then estimate the quantity of methylmercury. In general, the levels of total and organic mercury are considered to be fairly similar.

In 1977, the Medical Service of Health and Welfare Canada set up a monitoring program of the native communities (Wheatley, 1984, 1979). Individual results for the years 1977 to 1989 were obtained from Health and Welfare Canada. They were grouped into age classes for inclusion in the database.

In this report, we present the data for the most studied years, 1977, 1982 and 1984 (Table 4.1 ). The highest levels, over 10 ng/g of methylmercury, were found in the Inuit of the Baffin region. This result is slightly greater than the value of 6 ng/g considered acceptable by the World Health Organisation (WHO) (Wheatley, 1979) and is considerably higher than the mean level measured in a sample of 50 residents from Quebec City, where the mean concentration was under 0.6 ng/g in 78% of the people studied (Dewailly etal., 1991b).

117

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Table 4.1 Levels of methylmercury In the hair (jj.g/g) and blood (ng/L) of arctic native populations. Data from SBEC, 1991.

REGION TISSUE YEAR SEX N MEAN S.D. MAX

kair i W J F w~ 10.3 T T " 29.0 kair i W J

M 44" 14.5 7.7 47.6

kair i W J

F-M 146 11.2 6.6 37.0

kair

1982 F m 10.2 5.4 """55.6

kair

1982

M " 4 7 ' 14.4 5.4 '•"54.5

kair

1982

F-M ""136 11.6 5.5 54.5

blood 1477 F "17 45.1 14.5 4 4 3 " blood 1477

" M 18 32.1 22.3 89.5

blood 1477

F-M 45 44.7 14.3 89.5

blood

1664 F 31 22.2 ' 14.4 49.4

blood

1664

M 4 23.3 13.2 40.9

blood

1664

F-M 55 55.4 14.4 44.4

blia&mare hair 1477 F 7 ' " " W • 3.3 1 16.1 blia&mare hair 1477

M 11 10.7 3.3 15,é

blia&mare hair 1477

F-M 14 9 3.4 15.ê

blia&mare hair

1984 F 11 ' 7.2 5.1 18.5

blia&mare hair

1984

M 16 4.6 >.1 51.5

blia&mare hair

1984

F-M 43 8.1 6.1 21.5

Fort Smith hair 1977 F 83 3.7 3.0 15.3 Fort Smith hair 1977

M 47 4.7 4.4 51.4

Fort Smith hair 1977

F-M '" 156 4.1 3.7 51.5

Huoson hair 1977 F 57' 14.3 - é.3 ""36.5 Huoson hair 1977

M 1 5.3 • 4.6" 5.4

Huoson hair 1977

F-M ' 28 12.1 6.3 30.2

Inuvik hair H677 F 13é — ES"' é.1 34.7 Inuvik hair H677

M 74 4.4 4.6 57.4

Inuvik hair H677

F-M 214 4.9 5.5 36.7

Inuvik hair

1444 F 175 4.4 3.6 43.5

Inuvik hair

1444

M 114 4.7 3.5 55.6

Inuvik hair

1444

F-M 294 4.1 3.7 53:5"

Inuvik

blood 1444 '" F 244 7.4 6.1 34.4

Inuvik

blood 1444 '"

M 161 6.S 8.0 &2.1

Inuvik

blood 1444 '"

F-M 344 4.6 7.6 54.1

Keewatin hair 1477 F 74 4.4 3.4 17.5 Keewatin hair 1477

M 67 7.9 5.7 iè.2

Keewatin hair 1477

F-M 145 ,""7:,6m 4.4 44.5

KitiKmeot hair 1477 F ""54 " 5.ê 4.3 15.4 KitiKmeot hair 1477

M 47 6.1 4.é "47.7

KitiKmeot hair 1477

F-M 143 6.8 4.4 47.7

Yukon hair 19ft .... p 130 2.0 i i X» Yukon hair 19ft

M 146 1.7 1.4 "15.3

Yukon hair 19ft

F-M 236 1.4 1 '"Î:S" 12.3

Yukon

blood 1977 F 73 6.6 3.4 18.5

Yukon

blood 1977

M 75 6.4 3.7 51.7

Yukon

blood 1977

F-M 145 é.7 3.5 51.7

Region

Baffin

Ellesmere

Fort Smith

Hudson

Inuvik

Keewatin

Kitikmeot

Yukon

Localization SamDlinç y ^ r

Arctic Bay 1977 Broughton Island 1977 Cape Dorset 1977 Frobisher Bay 1977 Hall Beach 1977 Igloolik 1982 Lake Harbour 1977 Pangnirtung 1977 Pond Inlet 1977 & 1982

Grise Fjord 1977 Resolute Bay 1984

Detah 1977 Fort Liard 1977 Fort Providence 1977 Fort Resolution 1977 Fort Simpson 1977 Fort Smith 1977 Hay River 1977 Trout Lake 1977 Wrigley 1977 Yellowknife 1977

Sanikiluaq 1977

Arctic Red River 1977 Fort Franklin 1982 Fort Good Hope 1977 & 1982 Fort McPherson 1977 Fort Norman 1977 Inuvik 1977 Paulatuk 1977 Tuktoyaktuk 1977 & 1982

Baker Lake 1977 Chesterfield Inlet 1977 Coral Harbour 1977 Eskimo Point 1977 Rankin Inlet 1977 Repulse Bay 1977 Whale Cove 1977

Cambridge Bay 1977 Coppermine 1977 Gjoa Haven 1977 Pelly Bay 1977 Spence Bay 1977

Carcross 1977 Carmacks 1977 Dawson City 1977 Destruction Bay 1977 Eisa 1977 Haines Junction 1977 Mayo 1977 Old Crow 1977 Pelly Crossing 1977 Ross River 1977 Teslin 1977 Watson Lake 1977 Whitehorse 1977

119

No studies have been done on the origin of the mercury in the Baffin region, but it could be related to the presence of the metal in ringed seals and belugas, an important source of food for the Inuit of Baffin.

As is often the case, men are more contaminated than women, with some exceptions in the Inuvik and Yukon regions. This is a pattern frequently seen among native populations where, in general, men not only eat more but have a more traditional diet (Kuhnlein, 1989); on the other hand, women breast-feed their children for long periods, which tends to decrease their contaminant load.

A dataset covering 1977 to 1989 is available for the community of Clyde River, Baffin Island (Figure 4.2). The mean levels of methylmercury decreased over the years, but since the goal of the program was to test individuals at risk, the data are not a statistically valid sample of the population. Nevertheless, it is possible that the same trend applies to the whole village. Factors which could account for this decrease are a lower consumption of marine products, a decline in mercury levels in those products or both.

Cree and Inuit communities of Northern Quebec have also been participated in this program, but since 1982, the monitoring has been done at a local level. The James Bay Cree Health and Social Services have been monitoring mercury exposure among Crees, whereas the program for the Inuit of Hudson and Ungava Bay has been interrupted in 1985.

For 1987, the last year for which we have data, mercury levels in the hair of Crees from the Hudson region increase with age and reach a maximum of 124 ng/g in men (Table 4.2). Compared to the results from 1984, the people in charge of the monitoring program noticed a decrease in the percentage of the population with concentrations over 30 ng/g (Dumont et al., 1988). This was attributed to a change in diet. In that case, it would mean a lower consumption of fish from the dammed areas.

The inuit from the Ungava region seem less contaminated by mercury than the Crees from the Hudson region. The mean levels in the hair are low, under 6 |ig/g, except in the newborns where the mean levels in the blood can be as high as 214 (ig/L (Table 4.3). Comparisons between the two groups, however, are made difficult

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100

Table 4.3 Levels of mercury in the hair* (ng/g) and blood (ng/l) of Inuit from the Ungava region for 1983. (Data from Lapierre, 1990)

COMMUNITY TISSUE AGE SEX N MEAN MAX Aupaluk hair 1-44 p.

2 4.7 7.0 blood NB F 1 68.0 68.0

1-44 F 1 22.0 22.0 kangiqsualuj juaq hair 1-44 F 10 3.7 14.1

blood NB F-M 7 16.6 50.0

1-44 F 13 10.1 22.2 Kangiqsujuaq hair 1-44 F 13 3.2 8.1

blood NB F-M 2 15.2 27.6

1-44 F 11 7.8 19 Kangirsuk hair 1-44 F 8 4.5 9.4

blood NB F-M 4 24.0 40.0

1-44 F 6 17.7 27.0 Kuujjuaq hair 1-44 F-M 37 2.4 9.9

blood NB F-M 32 11.3 52.5

1-44 f -M 33 3.7 10.5 Quaqtaq hair 1-44 F 9 3.7 9.0

blood NB F 3 88.7 214

1-44 F 7 23.5 40.0 Tasiujaq hair 1-44 P 5 3.1 4.0

blood NÈ F-M 3 6.3 8.0

1-44 F 5 6.0 7.8

*The mean is calculated on samples taken from 1, 3 or 6 cm from the scalp. " N B : newborns

1 2 3

because of the differences in the grouping of the age classes and in the years of sampling.

The monitoring program was cancelled in 1985, as the levels of mercury were considered low. In a more recent study, done in 1988 but restricted to the village of Kuujjuaq, the mean levels in the blood were below the 20 ^g/L level judged acceptable by WHO. They were 14.1 and 6.8 ng/L in adults and children respectively.

In Greenland, Hansen showed that mercury levels were related to the consumption of marine mammals according to the different districts (Table 4.4). The lowest levels are found in the south-western district of Nuuk, the most industrialized part of the country. In the northwestern districts of Uummanaq, and the eastern districts of Angmagssalik and Ittoqqortormiit, subsistence fishing and hunting is still practiced, but it is in the northern districts of Avanersuaq and Siorapaluk that the Inuit life-style is the most traditional. In fact, it is in the latter district that the highest level of 170 M-g/L was found. In these areas, the mercury level exceeded 200 ng/L in 16% of the cases. According to WHO, neurological problems may start to appear at that concentration (Hansen, 1988).

In another study from Greenland, authors showed that mercury crosses the placental barrier and that the blood of a newborn may contain up to 80% more mercury than the blood of its mother (Hansen etal., 1984) (Table 4.4).

4 .1 .1 .2 Cadmium

Smoking is often the most determinant factor influencing cadmium levels in humans. For example, in a study in Quebec's Lower North Shore, the mean cadmium level in non-smokers was 0.8 jxg/L compared to 5.7 p.g/L in smokers (Dewailly etal.,

1991b). In another study, from Greenland, Hansen and Pedersen (1986) found a relationship between a diet rich in marine mammals and cadmium levels in the blood.

In the Baffin region, the Health and Welfare survey did not include information on the smoking habits of people, so we do not know the extent of the influence of this factor on the mean level of 7.7 jig/L (Table 4.5). The mean blood level in Ungava is also, at 5.3 |ig/L, higher than the ones observed in the populations from Greenland.

100

Table 4.4 Levels of mercury in the blood (ng/l) of Inuit from Greenland.

COMMUNITY SEX N MEAN S.D. COMMENT

Angmassalik1 F 41 28.0 13.6 Angmassalik1

F 21 47.8 23.9 mixed diet

Angmassalik1

F 35 51.9 25.6 traditional diet

Avanersuaq1 F 7 41.4 20.2 occidental diet Avanersuaq1

F 5 49.6 22.6 mixed diet

Avanersuaq1

F 8 73.3 33.5 traditional diet

Nuuk1 F 309 13.6 9.9 occidental diet Nuuk1

F 48 17.9 13.1 mixed diet

Nuuk1

F 10 27.4 14.9 traditional diet

Uummanaq1 F 31 29.7 16.5 occidental diet Uummanaq1

F 36 44.7 23.2 mixed diet

Uummanaq1

F 15 48.9 23.8 traditional diet

Avanersuaq2 F 23 74.3 34.3 less than 6 meals of marine mammals per week

Avanersuaq2

M 14 89.9 51.4 less than 6 meals of marine mammals per week

Avanersuaq2

F b 155.2 45 more than 6 meals of marine mammals per week

Avanersuaq2

M 6 153.8 64.6 more than 6 meals of marine mammals per week

Siorapaluk2 P 8 84.5 30 less than 6 meals of marine mammals per week

Siorapaluk2

M 8 135.0 36.7 less than 6 meals of marine mammals per week

Siorapaluk2

F 6 170.1 49.3 more than 6 meals of marine mammals per week

Siorapaluk2

M 16 164.6 63.7 more than 6 meals of marine mammals per week

Upernavik3 F 14 37.8 18.5 parturient women Upernavik3

13 65.1 28.1 cord blood

Ummanaq3 F 32 24.3 13.7 parturient women Ummanaq3

32 42.5 23.6 cord blood

Ittoqqortormiit3 F 17 10.4 5.4 parturient women Ittoqqortormiit3

17 19.2 13.9 cord blood

Angmagssalik3 F 31 38.7 22.7 parturient women Angmagssalik3

27 59.4 38.5 cord blood

1 From Hansen, 1988b; sampled between 1982 and 1986 2 From Hansen & Sloth Pedersen, 1986; sampled in 1983 3 From Hansen et al., 1984; sampled in 1981-1982

1 2 5

Table 4.5 Levels of cadmium in the hair (ng/g), blood (jxg/l) and urine (ng/l) of Inuit from Northern Canada and Greenland.

REGION COMMUNITY T I S S U E S E X N MEAN

Baffin1 Nanisivik blood F-M 19 7.7

Greenland2 Ittoggormiit hair M 26 0.1

Julianehab blood M 25 2.6

hair M 25 0.5

Nuuk blood M 50 2.8

hair M 50 0.4

Upernavik blood M 14 2.8

hair M 14 0.6

Uummanaq blood M 22 2.3

hair M 22 0.5

Angmagssalik3 blood F-M 28 1.11

Ungava4 Kuujjuaq hair F-M 62 0.20

blood F-M 68 5.3

urine F-M 68 3.6

1 Sampled in 1981; from SBEC, 1991 2 Sampled in 1979; from Hansen, 1981b 3 Sampled in 1981 ; from Hansen et al. 1985 4 Sampled in 1988; from Benedetti & Turcotte, 1989

100

In the former, the concentrations of cadmium could, in part, be related to the consumption of viscera of game species such as caribou (Archibald and Kosatsky, 1991 ; Benedetti and Turcotte, 1989).

4 .1 .1 .3 Lead

In Greenland, Hansen (1988) could not f ind any relationship between lead concentrations and diet. Exposure to lead is not, therefore, a problem particular to northern populations. Mean levels in that part of the world, are under the 350 p.g/L level considered acceptable in Europe (Table 4.6). In Nanisivik, Baffin region, the mean levels are similar to the mean concentration of 140 ng/L measured in Americans living in urban areas, and whose age varied between 6 months and 74 years (National Center for Health Statistics, 1984).

4 .1 .2 Organochlor ines

The presence of organochlorines in the arctic aquatic food chain is now well documented. However it is the quantities of wild food consumed by the people residing in northern regions, rather than the relatively low concentrat ions of contaminants in these food species, when compared to the levels measured further south, which are responsible for the exposure to organochlorines.

This exposure accounts for the accumulation of organochlorines in the tissues and biological liquids. Measuring the levels in blood lipids is the most reliable estimate of long term exposure, since those compounds are very persistent in the organism and tend to build up in the lipids.

Relative to heavy metals, little information is available on the levels of organochorines in northern populations.

In 1985, PCB (Aroclor 1260) levels were measured in the blood of 207 residents of Broughton Island (Table 4.7). Blood levels ranged from 3.9 ng/L (ppb) in girls

127

Table 4.6 Levels of lead in the blood (ng/l) of Inuit from Greenland and the Canadian Arctic.

REGION COMMUNITY SEX N MEAN S.D. COMMENT

Greenland1 Angmassalik 21 77.0 26 cord blood

F 24 82.0 22 parturient women

Ittoqqortormiit 17 78.0 21 cord blood

F 16 107.0 22 parturient women

Upernavik 13 65.0 29.0 cord blood

F 13 83.0 21.0 parturient women

Uummanaq 30 60.0 20.0 cord blood

F 30 75.0 28.0 parturient women

Baffin2 Nanisivik F 11 160.1 155.8

M 128 200.2 118.9

1 Sampled in 1981-1982; from Hansen etal., 1984. 2 Sampled in 1980; from SBEC, 1991.

100 128

Table 4.7 Levels of PCB in Inuit from Northern Canada and Greenland.

CONTAMINANT REGION COMMUNITY T I S S U E AGE S E X N MEAN MAX

• . ...

Arocior 1260 Baffin Broughton Island"! blood (W3/I)

<15 F 25 3.9 14.0

<15 M 21 5.0 15.0

15-44 F 67 3.9 14.0

15-44 M 54 7.2 23.0

45+ F 24 11.7 51.0

45+ M 16 11.4 22.0

Hudson Umiujaq to Saliuit2 milk fat F 24 3.6 14.7 m

whole milk (Hfl/I)

F 24 111.3 514

Ungava Kuujjuaq3 serum (W/l)

9-14 16 13.6 40.0

15-83 69 41.0 123.0

Hudson & Ungava

Kuujjuarapik to Kangiqsualujjuaq4

milk fat (mg/kg)

F 109 2.89 11.9

Aroclor 1254 Greenland Western Greenland5 fat (mg/kg, dry weight)

F 6 1.8 5,6

uongeners PCB-118 Hudson &

Ungava Kuujjuarapik to Kangiqsualujjuaq4

milk fat (mg/kg)

F 36 0.06 0.25

PCB-138 F 109 0.23 1.23

PCB-153 F 109 0.39 2.32

PCB-170 F 36 0.05 0.15

PCB-180 F 109 0.19 1.25

PCB-183 F 99 0.02 0.10

PCB-187 F 36 0.06 0.15

Non-ortho coplanars 3,3,4,4'-tetrachloro-biphenyl Hudson &

Ungava Kuujjuarapik to Kangiqsualujjuaq4

milk fat (ng/kg)

F 40 24.8 94.9

3,3'4,4',5-pentachloro-biphenyl

F 40 209.3 685.0

3,3'4,4',5,5-hexachloro-biphenyl

F 40 220.9 482.0

1 Sampled in 1985; from Kinloch, 1990. 2 Sampled in 1987-1988; from Dewailly and al. 1989. 3 Sampled in 1988; from Benedetti, 1990. 4 Sampled in 1989-1990; from Dewailly, 1991. 5 Sampled in 1972; from Clausen & Berg, 1975.

under 15 to 11.7 |j.g/L in women over 45. They are considered high compared to the blood levels measured in the general adult population where the means vary between 4 and 7 ng/L. Further south, in Kuujjuaq , Benedetti (1990) reported mean blood levels of 13.6 fig/L in the 9 to 14 age group (n=16) and 41 p.g/L in the 15 to 83 age group (n=69) (Table 4.7). Levels in adults from the Kuujjuaq area are 6 to 10 times higher than the ones measured in the general population.

The fatty tissues of six Inuit women hospitalized in Greenland in 1972 had levels of 1.8 mg/kg (dry weight) of PCB (Aroclor 1254) (Table 4.7) compared to a mean of 0.5 mg/kg in American women.

Analyses were also done on breast milk. In a first study, the authors reported high levels of PCB (Aroclor 1260) and DDE in the maternal milk of 24 Inuit women from the eastern Hudson Bay (Dewailly et al., 1989) (Tables 4.7 and 4.8). The mean level of Aroclor 1260 was 3.6 mg/kg in the milk fat compared to a level 0.77 mg/kg in women from Quebec City and Baie-Comeau. A similar difference was observed for DDE.

A more complete study which was conducted two years later on 109 milk samples taken from Northern Quebec Inuit women who were breast-feeding in 1989 or 1990, yielded similar results (Table 4.7) Mean PCB (Aroclor 1260) level in the milk fat was 2.89 mg/kg, while the mean in 572 women who had given birth in 22 hospitals across the province of Quebec was 0.52 mg/kg, or 5.5 times less (Dewailly et al., 1991a). The same difference was also found for the pesticides presented in Table 4.8.

In the course of that study, toxic PCB congeners (the non-ortho coplanars) were measured in the milk of 40 Inuit women and 96 women from the province of Quebec (Table 4.7). The results for the congeners Nos 77, 126 and 169 were 24.8, 209.3 and 220.9 ng/kg (milk fat) in the Inuit, compared to lower levels of 8.1, 80.5 and 32.7 ng/kg in the control group from Southern Quebec (Dewailly, 1991).

Dioxins and furans were also analyzed in the same groups (Table 4.9). The differences are not as important, but the levels of TCDD and OCDD are still three times higher in Inuit women. The levels of TCDF are, however, two to three times lower in the Inuit women than in the control group.

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131

Table 4.9 Levels of dibenzofurans and dioxins in the milk fat (ng/kg) of 40 Inuit women from the Hudson and Ungava regions (Sampled in 1989-1990; from Dewailly, 1991.)

CONTAMINANT MEAN

Dibenzofurans 2,3,7,8-TCDF 2.2

2,3,4,7,8-PECDF 6.7

1,2,3,4,7,8-HXCDF 3

1,2,3,6,7,8-HXCDF 2.2

2,3,4,6,7,8-HXCDF 1

1,2,3,4,6,7,8-HPCDF 6.7

OCDF 3.8

Dioxins 2,3,7,8-TCDD 6.25

1,2,3,7,8-PECDD 8

1,2,3(4+6)7,8-HXCDDs 33.3

1,2,3,7,8,9-HXCDD 5.5

1,2,3,4,6,7,8-HPCDD 37.4

OCDD 292.3

100

Studies by Dewailly (1991) and Clausen & Berg (1975) have also generated data on the concentration of organochlorinated pesticides in the lipids and milk fat of Inuit women from Northern Quebec and Greenland. In addition to DDE, those pesticides are heptachlor and its epoxide form (HEx), hexachlorobenzene (HCB), chlordane, endrin, dieldrin, aldrin and lindane (Table 4.8).

4.2 Dietary Contaminant Intake

It is possible to identify the food items which account for most of the contamination by examining the information on the contaminant levels measured in the edible tissues of the various food species, and on their consumption as estimated in diet or harvest surveys.

The largest concentrations of organochlorines have been found in the fatty tissues of the beluga, walrus and narwhal, and to a lesser degree, in the fat of the ringed and bearded seals. In general, contamination in fish and marine mammal meat is low.

For mercury, however, high levels of the metal have been found in fish, particularly in the lake trout and lake whitefish, but also in beluga meat. The liver of marine mammals is also loaded with heavy metals, mainly mercury and cadmium.

The curves in Figures 4.3 to 4.8 represent the daily food ration (g/day) that an adult of 70 kg can eat in order to respect the Acceptable Daily Intake (ADI) of a given contaminant under various levels of contamination. The minimum and maximum contaminant levels in the food species are taken from the database. In Figure 4.3, for example, consuming 20 grams of ringed seal blubber containing 3.5 pg/g of TCDD means the ingestion of 70 pg of TCDD, thus respecting the ADI of 1 pg/kg of body weight per day. The consumption should be lower for more contaminated food items. For example, eating 2 grams of blubber contaminated at 39 pg/g exceeds the ADI for an individual of 70 kg.

1 3 3

2,3,7,8-TCDD

350-1

i i i -rT~T

0.5 - r T - r

1.0 _ r T- r

1.5 i r i i l l i | i

2.5 3.0 T - r

0.0 2.0 rTr

3.5 4.0

Blubber of ringed seal MAX: 39 pg/g

r r _ r 0.0 0.5

I I J I 1

1.0 T 7 " 1.5

i | i 2.0

-i—r 2.5

i i | i i 3.0

1 I 1 1

3.5 4.0

2,3,7,8-TCDD levels in food (pg/g)

Figure 4.3 Quantity of food as a function of levels of 2,3,7,8-TCDD measured in the tissues of the various species that can be consumed in a day without exceeding an ADI of 70 pg/day.

1 3 4

Dieldrin

>» as 5 3 c o> <0 o •o o o o

c co

350 -q

300-=

250-f

200- ;

150- :

100

5 0 -

i—i I I | I i I—I—|—r-O.OO 0.05 0.10

1 I 1 ' 1 • I 1

0.15 0.20 1 I 1 1

0.25

B Muscle of fish species and marine mammals

E H Blubber of bearded seal

~i—[—i—r 0.30

Blubber of ringed seal

O.OO 1 I 1

0.05 i i i i I i i i i I i i i

0.15 0.20 • i i r I l

0.10 0.15 0.20 0.25 Dieldrin levels in food (|ig/g)

0.30

0.35

Blubber of beluga MAX: 1.2 pg/g Blubber of walrus MAX: 0.5 pg/g Blubber of narwhal MAX: 0.5 pg/g

- n 0.35

Figure 4.4 Quantity of food as function of levels of dieldrin measured in the tissues of the various species that can be consumed in a day without exceeding an ADI of 3.5 pg/day.

1 3 5

Total chlordane 350-,

0.5 0.6

Muscle of marine mammals and fish species

Muscle of arctic char and rock cod

Blubber of bearded seal

0.0 0.1 T T 1—

0.3 I

0.4 I

0.5 — 1 — r ~

0.2 0.3 0.4 0.5 0.6 0.7 0.8 Total chlordane levels in food (pg/g)

Blubber of ringed seal MAX: 2 pg/g Beluga MAX: 4.2 |ig/g Narwhal MAX: 1.9 |ig/g

t f— 0.9 1.0

Figure 4.5 Quantity of food as a function of levels of total chlordane measured in the tissues of the various species that can be consumed in a day without exceeding an ADI of 4.2 pg/day.

100 136

Mercury

350

1*300-o> "c 250-&

| 200-o £ 150-o £ 1 0 0 -c CO

§ 50

0.0 I I I I

0.5 I 1 r

1.0 1.5 i—i—|—i—i—i—i—|—i—i—i—i—|

2.0 2.5 3.0

Arctic char (Arctic)

Arctic char (Ungava)

Lake trout (Arctic)

Lake whitefish (Arctic)

Lake whitefish (Ungava)

r ~ r

0.0 • ' I

0.5 - r ~ 1.0

-i—r 1.5

i i i I i 2.0

Lake trout (Ungava) Lake trout (Hudson) MAX: 4.7 \iglg

Lake whitefish (Hudson) MAX: 4.6 pg/g Muscle of beluga MAX: 6.0 pg/g

T—I—i—i—i—i—| 2.5 3.0

Mercury levels in food (pg/g)

Figure 4.6 Quantity of food as a function of levels of mercury measured in the tissues of the various species that can be consumed in a day without exceeding an ADI of 21 pg/day.

350-1

>; 300 H (0 •o s 250q c B ? 200 •g

5 150-o

100 c (S

3 50 H

r—i—i—i | i—r

0.0 0.5

B Fish species

Total DDT

i | i i i i | i i i—i—|i i i—i | i i i—i | i—r—i—i—|—i—i i i—| 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Blubber of bearded seal

0.0 " n r "

0.5

Blubber of ringed seal

1 1 I 1

1.5 T 1 "

1.0 1.5 2.0 2.5 3.0 Total DDT levels in food (pg/g)

• * * i • 2.5

- T - r r

3.5

Blubber of narwhal MAX: 7 pg/g Beluga MAX: 9.7 pg/g

• • i 4.0

Figure 4.7 Quantity of food as a function of levels of total DDT measured in the tissues of the various species that can be consumed in a day without exceeding an ADI of 35 pg/day.

1 3 8

Total PCB

>v CO

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a> S a> -o o o

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0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

1 Muscle of fish species, bearded seal and beluga

WÊÊ Muscle of ringed seal Blubber of bearded seal

Blubber of ringed seal

Blubber of walrus MAX: 6.0 pg/g Narwhal MAX: 6.0 pg/g Beluga MAX: 6.7 pg/g

I i i i i I i i i i I i 0.0 0.5 1.0

» i l i i i i l 11 i i I 11 i i l i i i ' I 11 1 1 i 1 1 11 I 1 ' 11 I 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Total PCB levels in food (pg/g)

Figure 4.8 Quantity of food as a function of levels of total PCB measured in the tissues of the various species that can be consumed in a day without exceeding an ADI of 70 pg/day.

102

For PCBs (Table 4.8), the consumption of 700 grams of fish will not exceed the ADI, but 10 grams of beluga blubber contaminated at 6.7 |ig/g means the ingestion of 67 (ig of PCB, while the acceptable dose is 70 |ig for an adult of 70 kg (the ADI being 1 |ig per kg of body weight per day).

The presence of PCBs in people living in Northern Quebec, where the narwhal is mostly absent and the walrus hardly eaten, is probably related to the consumption of beluga blubber, which is somewhat contaminated, and of ringed seal, which is less contaminated but heavily consumed.

It is possible to estimate a daily intake for a contaminant by using the levels measured in the tissues of the various food species and the quantities consumed. We illustrate this process using the diet data collected on Broughton Island in 1985 (Kuhnlein, 1989). In table 4.10, we present the results of this exercise for four contaminants: dieldrin, total chlordane, DDT and its metabolite DDE, and total PCBs. A daily intake for one individual is calculated for each tissue and the proportion of the total daily intake each food item represented is also estimated. Thus, the food items responsible for more than 70% of the daily intake of the four organochlorines are the blubber and muktuk. This is due to the relatively high levels of organochlorines present in those fatty tissues, rather than to the consumption of those tissues which is moderate.

4 .3 Risk from Exposure to Chlorinated Pesticides

We limit our analysis to DDT (and DDE), PCB, chlordane and dieldrin, the main contaminants for which there is sufficient information to conduct a risk analysis.

In Table 4.11, the daily intake for each contaminant, as estimated in Table 4.10 for the Inuit of Broughton island, is expressed in microgram per kilogram of body weight, given an individual of 70 kg. To estimate the health risks associated with the ingestion of such doses, we used the ADI estimated by the USEPA (1991) or the provisional tolerable daily doses proposed by Health and Welfare Canada (1989), as presented in Table 4.11.

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Table 4.11 Daily intake (Dl) and acceptable daily intake (ADI) of 4 organochlorines

Contaminant Daily Intake ADI (Source) Ratio

((ig/kg-BW/day)* (^ig/kg-BW/day)* (DI/ADI)

Dieldrin 0.13 0.05 (EPA, 1990) 2.6

Chlordane 0.53 0.06 (EPA, 1989) 8.9

DDT 1.17 0.50 (EPA, 1987) 2.3

PCB 1.30 1.0 (SBEC, 1989) 1.3

* lig/kg-BW/day : microgram per kilogram of body weight, per day

102

The estimated daily intake for DDT and DDE is 1.2 (ig/kg/day. This dose is 2.3 times greater than the ADI of 0.5 ^g/kg/day established for DDT, whose structure is similar to DDE's. The USEPA has not determined a reference dose for DDE. The ADI for DDT is based on the results of a study done on rats. Minor hepatic lesions were observed at a dose of 0.25 mg/kg/day. The level at which no adverse effect was observed (NOAEL) was 0.05 mg/kg/day. The ADI was obtained by dividing this NOAEL by a security factor of 100 to account for possible inter-species differences between rats and humans, and for the presence of hypersensitive individuals in the population.

The estimated daily intake of 0.13 ng/kg/day for dieldrin is 2.6 times higher than the ADI for this organochlorine (0.05 |ig/kg/day). The USEPA determined a reference dose using a study in which an increase in liver weight and cellular changes (a localized proliferation of cells) were observed at a dose of 0.05 mg/kg/day. The level at which no adverse effect was observed (NOAEL) was 0.005 mg/kg/day. The ADI was again obtained by dividing this NOAEL by a security factor of 100 to account for possible inter-species differences between rats and humans, and for the presence of hypersensitive individuals in the population.

As for the summation of the chlordane isomers, the estimated daily intake is 0.53 |ig/kg/day and is nine times the ADI of 0.06 ng/kg/day established by the USEPA. This reference dose relies on studies done on rats exposed all their life to chlordane incorporated in their diet. Minor hepatic lesions developed in female rats that had received a dose of 0.273 mg/kg/day, but not in males. The NOAEL estimated from this study is 0.055 mg/kg/day. The ADI was obtained by dividing this NOAEL by a security factor of 1000 to account for 1) possible inter-species differences between rats and humans, for 2) the presence of hypersensitive individuals in the population and for 3) the absence of adequate chronic studies done on a second species of mammal and of studies on reproductive functions.

The lowest doses of PCB producing adverse effects are mainly affecting the reproduction and development as demonstrated in rhesus monkeys (ATSDR, 1989) and in humans (for a literature review on the subject, see Swain, 1991). In the rhesus monkey, it affected the foetus (abortions, resorptions, reduced weights at birth and stillbirths) and the reproduction (longer menstrual cycles, reduced progesterone levels

143

in the blood). These effects were observed at the lowest dose of Aroclor 1248 administered about 100 p.g/kg/day (Allen etal., 1979, 1980; Barsotti etal., 1976 in ATSDR, 1989). However polychlorinated furans, however, were detected in the mixture given to monkeys (1.7 ppm) which could explain, partly or entirely, the toxic effects observed. In another study, where furan-free Aroclor 1016 was administered, less toxic effects were observed (Barsotti and Van Miller, 1984, in ATSDR, 1989). In the group receiving 40 |ig/kg/day, the average weight of newborns was significantly lower than in the control group. The NOAEL identified in this study was 10 ng/kg/day. These studies helped in establishing the reference dose for PCBs. The reference dose proposed by Health and Welfare Canada is 1 ^g/kg/day (SBEC, 1989).

Epidemiological studies done on children from North Carolina, Michigan and Taiwan who had been exposed to PCBs, show diminished learning abilities (Jacobson etal., 1990; Gladen etal., 1988; Rogan etal., 1988). Such effects have also been observed in monkeys and seem to be related with the capacity of certain congeners to decrease dopamine neurone concentrations in the caudate, nucleus putamen, substantia nigra and hypothalamus (Seegal etal., 1990; Shain etal., 1991). On the basis of epidemiological studies, Tilson et al. (1990, in Swain, 1991) have identified a NOAEL of 0.027 jig/kg/day for the effect produced at the lowest dose, i.e. a decrease of the visual cognitive memory.

The estimated daily PCB intake for the Inuit from Broughton Island is 1.3 (ig/kg/day. This dose is superior to the ADI based on toxicological studies on rhesus monkeys and to the NOAEL based on epidemiological studies indicating a decline in the visual cognitive memory of children.

The fact that the dietary intakes estimated for the Broughton Island Inuit exceed the acceptable daily intakes is indicative of a possible health risk. The greatest concern are the risks associated with exposure to PCBs (effects on reproduction or on development). Making recommendations to modify dietary habits on the basis of these preliminary results is not, however, advised at this point. An exhaustive risk analysis, taking into account the benefits of a diet rich in marine products (Dewailly et al., 1991b) would be timely.

144

An in-depth analysis would entail knowing the blood levels of specific PCB congeners in Inuit, This type of data would also be needed for the monkeys used in experimental studies on PCBs. The mixtures of PCBs administered to the monkeys in t h e studies mentioned above are very different from those found in marine products. In t h e studies by Allen et al., the 1248 mixture administered was contaminated with a substantial quantity of PCDF (1.7 ppm), while in studies by Barsotti and Van Miller (1984) the 1016 mixture used was composed of congeners that were less chlorinated t h a n the typical combinations found in humans exposed to PCBs present in the environment this last being closer to Aroclor 1254 or 1260.

Interpreting the epidemiological studies suggesting a negative effect of PCBs on t he neurological development of children requires a better understanding of the effects o f being exposed to certain congeners. In all probability, the congeners responsible fo r those effects are not the same as the ones involved in other types of disorders that have also been noted. Neurochemical changes observed in the brains of monkeys following the administration of Aroclor 1016 are associated with the accumulation, in th is organ, of three ortho-substituted nonplanar congeners (# 28, 47 and 52) (Seegal etal., 1990).

When DDT and DDE, dieldrin, chlordane and PCBs are administered in large doses to laboratory animals throughout their lifetime, an increase in the incidence of l iver cancer, notably in mice, are observed (USEPA, 1991; SBEC, 1989). These substances are not powerful genotoxic agents. They are more probably carcinogens o f the promoter type. Consequently, we think that the relatively low doses to which the Broughton Island Inuit are exposed result in a low risk of developing cancer. We believe that the effects on reproduction and development are more of a concern and should be closely monitored by public health groups.

102

CONCLUSION AND RECOMMENDATIONS

It has become clear, after reviewing the available information on the levels of contaminants in northern food species and in humans, that large gaps in the data exist. The state of contamination of certain species such as the Canada goose, harp seal, walrus, lake whitefish, lake trout, rock cod and burbot is little known. In general, few studies have been done on birds and the Yukon Territory has been largely ignored. Studies on human contamination have concentrated mainly on the eastern populations of Greenland, Baffin, Ungava and Hudson.

Gaps in our knowledge of TCDD, endrin, lindane, heptachlor epoxide, lead and methoxychlor make it difficult to relate the levels of contaminants to the position of the species in the food chain. Methoxychlor in particular will have to be kept in watch in the future since it will probably be the worldwide favored replacement for DDT.

Studies on organochlorines have concentrated on the beluga, polar bear and ringed seal. It is in the blubber of the beluga (and of the narwhal when data are available) as well as in the lipids of the polar bear that the highest levels of dieldrin, chlordane, PCBs and HCB have been measured. In the Keewatin region, the levels of dieldrin, chlordane and DDT in the fatty tissues of the polar bear and its favorite prey, the ringed seal, are higher than the values measured in other regions for the same species. Fish studies on organochlorines are limited to arctic char.

Mercury in fish was intensely studied n Northern Quebec, more so than in other regions. Data on mercury levels in mammals pertain mostly to the liver and muscle of the beluga and polar bear which last has a higher degree of contamination. Data on levels of cadmium in fish and waterfowl are rare, even if the concentrations found in the liver of the common eider from Greenland are fairly high. As for lead, the limited levels are only available for the ringed seal and the beluga. The latter shows higher levels in the Keewatin and Hudson regions.

Only a few studies have looked at the state of contamination of the human populations living in the North, and most of them were conducted in the eastern regions. Only mercury has been studied across our study area, but most of the data were taken before 1980. Some features stand out: (1) fish, beluga flesh and liver of marine mammals are an important source of mercury; (2) Crees in general are more

149

contaminated than Inuit; (3) women are generally less contaminated than men; and (4)

mercury levels tend to decrease with time.

Available data on cadmium, lead and organochlorines are restricted to populations of Greenland and the regions of Baffin, Ungava and Hudson. As for cadmium, in addition to smoking, the consumption of marine mammal liver and viscera of caribou and other game species seem to be a source of contamination. In one study from Greenland, a relation was found between heavy consumers of marine mammals and cadmium levels. In studies on lead, no relationship was found between the diet and the blood levels.

Organochlorine contamination seems to be related to the diet of people. The main source is the fatty tissues of marine mammals. There is, however, only a limited set of data on contamination of organochlorines in humans of northern regions. The blood levels of PCBs and DDE measured in natives from Northern Quebec are 6 to 10 times higher than in the general population living south. Levels of other organochlorines, such as heptachlor epoxide, HCB, dieldrin, chlordane and endrine, are also superior in the people of the North.

The database developed from this project can be used to estimate the doses to which are exposed the human populations of the northern regions and to identify possible populations at risk which should then be monitored by public health organizations. This approach was applied in this report using diet survey data from Broughton Island as an example.

In view of what was discussed above , the following recommendations are made:

(1 ) Further studies are needed on the diet of the various native population living in the northern regions in order to identify the main species consumed;

(2) Efforts should be made to determine adequate contamination levels of the most commonly eaten species in each region. These samples should be taken from fishing and hunting sites;

150

(3) In order to orient future research on the health of populations living in northern regions, a theoretical analysis of the health risks should be undertaken for each population . Benefits of a traditional diet, notably in protecting against cardiovascular diseases, should be considered before making recommendations on the diet of native populations.

(4) In order to realize these analyses, levels of contaminant uptake can be estimated using dietary habits and the information on contamination level compiled in our database. We therefore stress the importance of updating the database and to include if needed other species of importance to native diets. Furthermore, studies on the levels of organochlorines in humans should be extended to the populations of Keewatin, Kitikmeot, Fort Smith, Inuvik, Yukon and Ellesmere.

(5) An assessment of the state of the northern environment should be undertaken and recommendations should be made to limit the use of persistent organochlorinated compounds and metals.

102

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