Organic contaminants in Arctic CaribouOrganic contaminants in Arctic Caribou

Contaminants in Canadian Arctic CaribouMary Gamberg, Northern Contaminants Program

Whitehorse, Yukon

Caribou hunter, Horton Lake, NWT. Photo courtesy of Susan Kutz

Cadmium is a toxic metal of concern that has been found at high levels in some caribou herds

in the Arctic. Cadmium accumulates in the kidneys and livers over time, so older animals

have a higher body burden than younger animals. The major source of cadmium to the Arctic is the production of lead and zinc. Cadmium, as a by-

product of this process, is released into the atmosphere and the long-range movement of air

masses transports it to the Arctic.

Mercury is a toxic metal of concern that has been found in caribou kidneys across the Arctic.

Mercury occurs naturally as elemental mercury and as organic and inorganic compounds.

Methyl mercury is more available to animals than inorganic mercury and can affect the

nervous system, particularly of the growing foetus and the young. The primary source of mercury to the Arctic is the burning of fossil

fuels, particularly coal, and waste incineration.

A health advisory was issued from Yukon Health and Social Services in 1993 advising consumers to limit their consumption of kidneys and livers from some Yukon caribou. Cadmium does not accumulate to high levels in

meat of caribou.

NO HEALTH ADVISORY HAS BEEN ISSUED ON THE CONSUMPTION OF CARIBOU MEAT

Overall, renal mercury in the Porcupine caribou has not increased or decreased over the past decade. It does appear to cycle, probably with local environmental factors such as temperature and precipitation. Care should be taken when attempting to infer a temporal trend from mercury tissue concentrations from a few widely separated years.

Methods

We work with hunters to obtain samples from successful caribou hunts. They provide:Whole kidneys – analyzed for metalsLiver – some analyzed for organic contaminantsMuscle – some analyzed for metals or organicsTeeth – used to age the caribou

Tissues are analyzed for contaminants by the National Laboratory for Environmental Testing (Environment Canada, Burlington).

Results are reported in a synopsis report prepared for the Northern Contaminants Program each spring and communicated to the communities using a variety of methods.

Average total Hg intake

020000400006000080000

100000120000140000160000180000

1 28 55 82 109 136 163 190 217 244 271 298 325 352

Julian

Nan

og

ram

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Bull Cow Cow w Bulls

MERCURY INTAKE BY PORCUPINE CARIBOUMERCURY INTAKE BY PORCUPINE CARIBOU

Mercury was measured in caribou forage from the Porcupine caribou calving grounds and the wintering area.

A Canadian Wildlife Service forage intake model was adapted to estimate mercury (total and methyl) intake over a calendar year, by Porcupine caribou bulls, cows and cows with bulls (ie. non-pregnant cows that did not travel early to the calving grounds).

There was no difference in mercury intake between cows that did or did not travel to the calving grounds. However, cows and bulls take in roughly the same total amount of mercury, since females need to eat more (due to their smaller body size and reproduction). Therefore they eat proportionally more mercury and have proportionally higher concentrations in their kidneys.

Female caribou tend to have higher concentrations of mercury than

males.

In general, organic contaminant levels are low in caribou (as in most of the

terrestrial system). New, or ‘emerging’ contaminants predominate (i.e. PFCAs

and PBDE 209) in organic contaminants in Arctic caribou. However overall levels are low, particularly in comparison with

marine mammals.

Fluorinated compounds such as PFOS are used in the production of fabric

protectors, stain repellents and fire –fighting foams.

PFOS and related chemicals that degrade to it have been banned in Canada and were withdrawn from

commerce by the main manufacturer (3M) in 2001. The precursors of the

PFCAs – fluorotelomer alcohols continue to be used and our expectation is that

PFCAs will increase over time.

Many thanks to the hunters and biologists who submitted samples to this program, and to the staff of Yukon Environment for their continuing support, particularly Philip Merchant and Angela Milani. Thanks to Derek Muir for much collaboration and Xiaowa Wang for technical assistance (NLET). Thanks to Don Russell for creating the mercury intake model for the Porcupine caribou and many helpful discussions.

This project was funded by the Northern Contaminants Program and supported by the Yukon Conservation Society and Alpine Aviation Ltd.

ACKNOWLEDGEMENTSACKNOWLEDGEMENTS

GEOGRAPHICAL TRENDSGEOGRAPHICAL TRENDS

Affaires indiennes Indian and Northernet du Nord Canada Affairs Canada

Qamanirjuaq

Porcupine

BluenoseEast

Beverly

GeorgeRiver

Bathurst

Dolphin and Union

150 ppm

Renal cadmium concentrations in 4-6 year old caribou from the Canadian Arctic (g/g dry weight)

Renal mercury (total) concentrations in fall-collected male caribou from the Canadian Arctic (g/g dry weight)

Objective

To determine levels of and temporal trends in contaminants in Arctic caribou in order to:

Provide information to Northerners regarding contaminants in this traditional food, so that they may make informed choices about food consumption.

Provide information to wildlife managers regarding possible health effects of contaminants on Arctic caribou populations

Further understand the fate and effects of contaminant deposition and transport to the Canadian Arctic

Qamanirjuaq

Porcupine

GeorgeRiver

Bathurst

Dolphin and Union

0

1

2

3

4

5 ppm

Renal cadmium in barren-ground caribou indicates a slight increase from east to west in the Canadian Arctic while renal mercury indicates the opposite geographical trend. Both trends likely reflect a combination of naturally occurring local metals as well as atmospheric deposition of cadmium and mercury from atmospheric long-range transport from North America, Europe and Asia.

Cadmium

MercuryORGANIC CONTAMINANTSORGANIC CONTAMINANTS

Kidneys Livers Meat

Porcupine Caribou

24 12 All you want

Tay Caribou 7 4 All you want

Contaminant Porcupine (Yukon)

Qamanirjuaq (Nunavut)(ng/g wet weight)

-HCH 0.08 ± 0.03 0.13 ±0.04

-HCH 0.11 ± 0.03 0.09 ±0.05

-HCH <0.01 <0.01

HCB 1.69 ±1.85 0.53 ± 0.17

Heptachlor Epoxide

0.12 ± 0.07 0.26 ±0.14

Oxychlordane 0.56 ± 0.43 0.41 ± 0.17

p,p-DDE 0.03 ±0.01 0.06 ±0.05

PCB 18 0.04 ± 0.03 0.07 ±0.05

PCB 52 0.32 ±0.22 0.53 ±0.43

PCB 153 0.09 ±0.05 0.13 ±0.09

PBDE 209 1.34 ± 1.85 2.15 ±3.98

-Endosulfan 0.02 ±0.01 0.03 ± 0.01

PFOS 0.01-1.72  

PFCAs 2.0-7.8  

CADMIUM AND MERCURYCADMIUM AND MERCURY

TEMPORAL TRENDSTEMPORAL TRENDS

Average Methyl Hg intake

0

500

1000

1500

2000

2500

3000

3500

1 27 53 79 105 131 157 183 209 235 261 287 313 339 365

Julian

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Bull Cow Cow w Bulls