Trace Element Concentrations in Bearded Seals (Erignathus barbatus) Near Red Dog Mine Compared to Other Locations in Alaska

Abstract

To determine if bearded seals (Erignathus barbatus) harvested near a zinc and lead mine (Red Dog, Alaska , USA) by subsistence hunters from Kivalina, Alaska, were as safe to eat as bearded seals from other locations in Alaska, we compared 19 trace element concentrations in liver tissue. Liver concentrations from nine bearded seals harvested near the Red Dog Mine (RDM) port site were compared with 15 bearded seals from two reference sites (Hooper Bay and Little Diomede, Alaska, USA). Concentrations did not differ by gender, but we found statistically significant trends in concentrations of cadmium, mercury, manganese, selenium, and vanadium with age. Arsenic and copper were the only elements found to be more concentrated in the liver of bearded seals harvested near RDM than in the other locations. The predominant form of arsenic in marine mammals is known to be a nontoxic organic form, not the toxic inorganic form, and copper is an essential element. Although elevated near RDM, neither element was found at concentrations that presented health risks. We found no evidence that bearded seals harvested near RDM were less safe to eat or that trace element concentrations were greater than those found in bearded seals harvested elsewhere in Alaska or Canada.

Mercury and selenium concentrations in skeletal muscle, liver, and regions of the heart and kidney in bearded seals from Alaska, USA

“…In the present study, liver had higher [THg] and [TSe] than any other tissues analyzed (Table ), consistent with other studies . Even though [THg] is highest in liver, it is known that in adult seals approximately 90% is in the form of Hg 2+ , most of which (approximately 53%) is bound to some form of Se and therefore likely to be biologically inactive .…”

“…Even though [THg] is highest in liver, it is known that in adult seals approximately 90% is in the form of Hg 2+ , most of which (approximately 53%) is bound to some form of Se and therefore likely to be biologically inactive . Liver [THg] and [TSe] in the present study were slightly lower but within the range ([THg] range = 0.64–20.44 and [Se] range = 0.75–23.20 ; [THg] range = 1.92–5.22 and [Se] range, 3.40–6.50 ) of previous bearded seal studies.…”

“…Population health and status of bearded seals have been monitored since 1962 by the Alaska Department of Fish and Game in cooperation with the Alaska Native subsistence harvest. As an Arctic species, bearded seals are exposed to contaminants such as perfluorinated pollutants , organochlorines, and heavy metals such as Hg .…”

“…The present study measured [THg] in different regions (intratissular comparisons) of the heart (each chamber wall and the septum) and kidney (cortex and medulla), and compared these values with [THg] in liver and skeletal muscle tissue (intertissular comparisons) to understand the regional distribution of [THg] within and among seal tissues. In addition, we measured [TSe] and Se:Hg molar ratios in heart left ventricle and kidney regions (cortex and medulla) to assess regional distribution and relative potential defense mechanisms of Se against Hg toxicosis.…”

Habitat selection and seasonal movements of young bearded seals (Erignathus barbatus) in the Bering Sea

“…There is considerable uncertainty associated with the field classification of age in young bearded seals. Yet, based on their standard lengths [ 31 ] and the frequent presence of a characteristic “T” shaped hair coloration on their forehead, all captured seals were thought to be less than 2 years old, with most being young-of-the-year animals (i.e., approximately 6 months old). Seals were captured using specially designed large-mesh (12 inch stretched) nylon twine nets.…”