Polar bear

Polar Bears Use Triacylglycerols to Survive Long Periods of Fasting... 

Ironically, the word Arctic comes from the ancient Greeks, who understood that the northernmost part of the earth lay under the stars of the constellation Ursa Major, the Great Bear. Although unaware of the polar bear, they called this region Arktikos, which means the country of the great bear. ... 

Letcher RJ, RJ Norstrom, DCG Muir (1998) Biotransformation versus bioaccumulation sources of methyl sulfone PCB and 4,4 -DDE metabolites in polar bear food chain. Environ Sci Technol 32 1656-1661. 

Marine mammals ringed seal, harbor seal, harbor porpoise, beluga whale, narwhal, polar bear. 

Ramsay, M. A. and Hobson, K. A. (1991) Polar bears make little use of terrestrial food webs evidence from stable carbon isotope analysis. Oecologia 86, 598 600. 

While the human body can remove an excess of any water-soluble vitamin, excesses of fat-soluble vitamins are more serious. Early arctic explorers discovered that the Inuit regarded seal liver and polar bear liver as taboo and must not be eaten. Those explorers who ignored this advice risked retinol poisoning as the livers of both these species are rich in retinol (vitamin A) that can not be excreted. The effects of retinol poisoning are extremely unpleasant. It is for this reason that fortification with fat-soluble vitamins is not likely to be undertaken. 

In mammals, cadmium inhibits copper absorption across the intestinal mucosa (Aaseth and Norseth 1986). Intercorrelations of copper with cadmium and zinc in livers of polar bears (Ursus maritimus) are probably mediated by metallothioneins, which may contain all three metals (Braune etal. 1991). In rats, copper protects against nephrotoxicity induced by cadmium, provided that copper is administered 24 h prior to cadmium insult. Specifically, rats given 12.5 mg Cu/kg BW by way of subcutaneous injection 24 h before receiving 0.4 mg Cd/kg BW — when compared to a group receiving Cd alone — did not have excessive calcium in urine and renal cortex or excessive protein in urine. Thus, 2.8 mg Cu/kg BW protects against 0.25 mg Cd/kg BW (Liu et al. 1992). 

Marine mammals usually contain less than 44 mg Cu/kg DW in all tissues except livers. Copper in livers seldom exceeds 116 mg/kg DW except in polar bears (146 mg/kg DW), and manatees, Trichechus manatus, (1200 mg/kg DW) from a copper-contaminated site (Table 3.3). Maximum copper concentrations in terrestrial mammals from all collection sites are usually less than 29 mg/kg DW in all tissues except kidneys (108 mg/kg DW) and livers (1078 mg/kg DW Table 3.3). 

Braune, B.M., R.J. Norstrom, M.P. Wong, B.T. Collins, and J. Lee. 1991. Geographical distribution of metals in livers of polar bears from the Northwest Territories, Canada. Sci. Total Environ. 100 283-299. 

Norheim, G., J.U. Skaare, and O. Wiig. 1992. Some heavy metals, essential elements, and chlorinated hydrocarbons in polar bear (Ursus maritimus) at Svalbard. Environ. Pollut. 77 51-57. 

Polar bear, Ursus maritimus Alaska 1972 total mercury young vs. adults Northern area ... 

Bom, E.W., A. Renzoni, and R. Dietz. 1991. Total mercury in hair of polar bears (Ursus maritimus) from Greenland and Svalbard. Polar Res. 9 113-120. 

Lentfer, J.W. and W.A. Galster. 1987. Mercury in polar bears from Alaska. Jour. Wildl. Dis. 23 338-341. 

Polar bear, Ursus maritimus-, Northwest Territories, Canada, 1984 liver California sea lion, Zalophus californianus-, recent mothers 0.21-0.54 DW 50... 

Polar bear, Ursus maritimus adipose tissue adults known range 1989-93 total chlordanes 1952 (727-4632) LW 110... 

Norstrom, R.J., S.E. Belikov, E.W. Born, G.W. Garner, B. Malone, S. Olpinski, M.A. Ramsay, S. Schliebe, I. Stirling, M.S. Stishov, M.K. Taylor, and O. Wiig. 1998. Chlorinated hydrocarbon contaminants in polar bears from eastern Russia, North America, Greenland, and Svalbard biomonitoring of Arctic pollution. Arch. Environ. Contam. Toxicol. 35 354-367. 

Polischuk, S.C., R.J. Letcher, R.J. Norstrom, and M.A. Ramsay. 1995. Preliminary results of fasting on the kinetics of organochlorines in polar bears (IJrsus maritimus). Sci. Total Environ. 160/161 465-472. 

Total PCBs in adipose tissue of polar bears (Ursus maritimus) throughout their known range, and collected between 1989 and 1993, are as high as 24.3 mg/kg on a lipid weight basis and are dominated by PCBs 153 (46% of total PCBs), 180 (18.5%), 170/190 (8.6%), and 99 (8.3%)... 

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