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We compared animals from a caribou (Rangifer tarandus) mortality event in the area of Point Hope and Chariot (Cape Thompson), Alaska (USA) in 1995 to hunter-killed caribou from reference sites (Barrow, Red Dog Mine, and Teshekpuk Lake, Alaska). Gross and histologic endpoints, and element levels (As, Cd, Cu, Pb, Zn, Fe) were evaluated. Starvation/malnutrition were major factors leading to death or severe weakness as very little or no fat (very low body condition scores) and serous atrophy of fat (marrow cavity and histologically) were more prevalent in caribou associated with the mortality event as compared to reference sites animals. Accumulation of hepatic hemosiderin in Kuppfer cells was noted as an indicator of cachexia. Levels of lead in feces and liver, copper the rumen contents, and arsenic in muscle were higher in caribou harvested near Red Dog Mine and might be expected in the mineral rich area, but were not at a level of concern for toxicoses. Kidney levels of cadmium were significantly increased with increasing age, and presents a potential concern for human consumers, and is an expected finding. We concluded that heavy metals played no role in the mortality event and that caribou starved. Further investigation of regional minerals differences is required to understand the sources and transport mechanisms to explain these findings and to properly address mining activity impacts. Mortality events on the north slope of Alaska are not uncommon and likely involve starvation as described here, but in most cases are not investigated, even though recent industrial activities have heightened concern.
Moose (Alces alces) found dead (FD) and hunter-killed (HK) in 1995 on the north slope of Alaska (Colville River drainage) were evaluated for heavy metal and mineral status. Compared to previous reports for moose and domestic cattle, and data presented here from Alaska moose outside the Colville River area, levels of copper (Cu) were determined to be low in hoof, hair, liver, kidney, rumen contents, and muscle for these north slope moose. Iron (Fe) was low in muscle as well. These findings, in conjunction with evidence of poor calf survival and adult mortality prompted investigation of a mineral deficiency in moose (serum, blood, and hair) captured in the spring of 1996 and 1997. Captured males had higher Ca, Zn and Cu levels in hair than captured females. Female moose hair samples were determined to be low (deficient) in Cu, Ca, Fe, and Se with mean levels (ppm) of 2.77, 599.7, 37.4, and 0.30, respectively. Serum Cu level was low, and to a lesser degree Zn was deficient as well. Whole blood (1997 only) was marginally deficient in Se and all animals were deficient in Cu. Based on whole blood, sera and hair, Cu levels were considered low for moose captured in spring 1996 and 1997 in the Colville River area as compared to published data and other populations evaluated in this study. Low levels of ceruloplasmin activity support this Cu deficiency theory. Evidence indicates that these moose are deficient in Cu and other minerals; however, the remote location precluded sufficient examination of animals to associate this apparent deficiency with direct effects or lesions. Renal levels of Cd increased with age at expected levels.
Caribou (Rangifer tarandus) were sampled (1995-96) from a mortality event near the Project Chariot site (NW Alaska), the location of a radiotracer experiment in the 1960’s, and reference sites. Radionuclide levels in muscle and bone and the cause(s) of the mortality were determined due to concerns of local residents. Bone gross alpha mean activity (n = 65) was 130.0 Bq/kg, and varied significantly (< 0.01) from 73.3 to 168.0 Bq/kg among locations. Bone and muscle gross beta mean activity was 510.4 and 9.78 Bq/kg. Bone strontium-90 mean activity (n = 58) was 137.8 Bq/kg. Muscle potassium-40 mean activity (n = 65) was 183.0 Bq/kg, and significantly varied from 76.0 to 104.4 Bq/kg by location. Muscle cesium-137 mean activity (n = 65) was 6.67 Bq/kg, ranged significantly from 0.74 to 15.6 Bq/kg by location, and increased with increasing body condition score. Bone potassium-40 mean activity ranged from 18.9 to 47.4 Bq/kg, and muscle strontium-90 ranged from 8.89 to 20.0 Bq/kg. Radionuclide concentrations were at expected levels and low in some cases as compared to Canadian caribou studies.