|
Biological
Characteristics
Species |
Ursus
maritimus is a one of three
North American species in the Family Ursidae. Compared to the black bear (U.
americanus) and the brown bear (U. arctos), the polar bear has an
elongated neck and comparatively smaller head, with a stocky body that lacks
a shoulder hump. Polar bears are completely furred except for the tip of the
nose, which is black along with the skin and the lips (Manning, 1971). Polar
bear fur appears white when it is clean and in even sunlight, although it is without
pigment (DeMaster and Stirling, 1981). At birth, polar bears weigh approximately
600 grams (Blix and Lentfer, 1979), but continue to grow rapidly, with adult
males weighing from 300 to 800 kilograms and reaching 2.5 meters in length
from the tip of the nose to the tail. Adult female polar bears are comparably
smaller, weighing 150 to 300 kg and measuring 1.8 to 2 meters in length (DeMaster
and Stirling, 1981). |
Status in Estuarine and Coastal Areas |
The
polar bear is the apical predator of the Arctic marine ecosystem, and their preferred
habitat is the pack ice of the |
Abundance and Range |
Polar
bears are circumpolar, occurring only in the Northern Hemisphere. Their range
is determined by the Arctic ice pack and the landfast ice of the surrounding
coastal areas. They will range during the winter along the southern edge of
the ice pack or northern edge of ice formed off the coasts of the continents,
while in the summer they will remain at the edge of the receding ice pack or
in areas with landfast ice. Six populations of polar bears include Wrangel Island
and western |
Site Fidelity |
It has been assumed that concentrated denning areas are maintained by fidelity of individual females to those sites. Pregnant females return to areas where they have successfully denned in the past (Uspenski and Kistchinski, 1972). |
Ease of Census |
Moderate |
Feeding Habits |
Polar bears are carnivorous, preying mainly on ringed seals, but they also hunt bearded seals, harp seals, hooded seals, walruses, sea birds, small mammals, and fish. They also may scavenge carrion of seals, walruses, or whales. They often eat only the high calorie blubber, which leads to the development of an insulating layer of fat, allowing the bears to store energy for times when food is scarce. If trapped on land for too long in the summer, polar bears will resort to eating vegetation (DeMaster and Stirling, 1981). |
I. |
Organochlorine
Contamination |
1. |
Blood plasma samples taken from 32 polar bears collected in 1967 from eastern Svalbard were analyzed for organochlorines and were then compared with values from 1993-1994 (Derocher et al., 2003). The following are the geometric means of PCB concentrations (ng/g wet wt) in blood plasma listed as (adult males, 1967, N=24/adult males, 1993-1994, N=24/adult females, 1967, N=9/adult females, 1993-1994, N=21/subadults, 1967, N=9): PCB-28(0.8/-/0.6/-/0.7); PCB-33(0.8/-/0.6/-/0.6), PCB-52(0.4/-/0.3/-/0.3,) PCB-74(0.2/-/0.2/-/0.2), PCB-99(1.9/2.5/1.5/5.0/3.9), PCB-101(0.2/-/0.2/-/0.1), PCB-105(0.2/0.1/0.2/0.1/0.2), PCB-118(0.5/0.3/0.5/0.3/0.5), PCB-128(0.1/0.1/0.1/0.2/0.1), PCB-138(1.8/4.7/1.7/6.6/3.2), PCB-141(0.0/-/0.0/-/0.0), PCB-149(0.0/-/0.0/-/0.0), PCB-153(8.2/23.3/5.9/30.5/15.4) PCB-156(0.5/0.8/0.3/1.0/0.6), PCB-157(0.2/0.9/0.1/0.9/0.3), PCB-167(0.0/0/0.0/0/0.0), PCB-170(2.1/8.7/1.2/7.8/3.4), PCB-180(5.1/13.4/3.4/13.5/7.6), PCB-183(0.2/-/0.2/-/0.3) PCB-187(0.1/0.0/0.1/0.1/0.1), PCB-189(0.1/-/0.0/-/0.1), PCB-194(1.0/4.8/0.5/4.1/0.8), PCB-206(0.5/0.7/0.4/0.7/0.4), PCB-209(0.3/0.3/0.3/0.4/0.3). The following are the geometric mean concentrations of pesticides found in the blood plasma from polar bears captured in 1967 listed as (adult males, N=24/adult females, N=9/subadults, N=9): o,p-DDT (0.0/0.0/0.0), p,p-DDT (0.6/0.2/0.1), o,p-DDE (0.0/0.0/0.0), p,p-DDE (1.7/1.4/1.6), o,p-DDD (0.0/0.0/0.0), p,p-DDD (0.4/0.5/0.3), ∑DDT (2.8/2.2/2.3), cis-CHL(0.0/0.0/0.0), trans-CHL (0.0/0.0/0.0), cis-nonachlor (0.0/0.0/0.0), trans-nonachlor (0.3/0.2/0.4), oxychlordane (1.3/1.5/4.6), heptachlor (0.1/0.1/0.1), ∑CHL (1.8/2.0/5.2), α-HCH (0.8/0.5/0.8), β-HCH (1.4/0.6/2.0), γ-HCH (0.1/0.1/0.1), ∑HCH (2.5/1.3/2.9). Differences in the organochlorine levels measured between 1967 and 1993-1994 are as follows: decreased in both sexes for PCB187 and p,p-DDE, unchanged in both sexes for PCBs 105, 118, 209, and HCH, increased in females for PCBs 99, 128, and CHL, and increased in both sexes for PCBs 138, 153, 156, 157, 170, 180, 194, and 206. |
2. |
Organochlorine
residue levels were determined in muscle, brain, and adipose tissues of polar
bears inhabiting waters of the Canadian Arctic and subarctic during 1968-1972
(Bowes and Jonkel, 1975). The following are the concentrations (µg/g
wet wt) listed by age/sex (PCB/DDE/DDT): 8/m (7.37/0.350/0.162); 7/m (3.89/0.268/-); 7/m
(0.194/0.019/0.015); cub/f (0.203/0.005/0.005); cub/m (0.090/0.009/0.003);
2.5/m (0.140/0.008/0.014); 6-7/m (0.713/0.005/0.002); -/f (0.089/0.0060.006);
-/f (0.057/0.005/0.006); -/f (0.061/0.004/-); 10/f (4.12/0.432/0.214); a/f
(0.190/0.009/0.010); 10-15/m (11.8/0.848/0.504); 17m (1.47/0.046/-); 17/m
(0.124/0.007/-); 12/f (0.043/0.008/0.003); 4.5/m (0.039/0.006/0.004); 4.5/m
(3.80/0.634/0.414); 10/f (0.026/0.004/0.006); 4/m (0.102/0.011/0.006); 3/m
(0.202/0.003/-); 5/f (0.012/0.001/-); 22/m (0.130/0.023/0.004); -/f
(1.42/0.105/-); 15/m (0.023/0.001/0.001); 6-7/f (0.038/0.001/-); cub/m
(1.13/0.032/-); 17/m (0.025/0.003/0.005); 4/m (0.018/0.002/0.003); 5.5/m
(2.12/0.183/0.122); 2-3/- (3.87/0.080/-); 4/m (0.030/0.005/-); 6/f
(0.030/0.004/-); 6/f (0.010/0.001/-); 15/f (2.89/0.108/-); 18/f
(2.84/0.107/0.055); 17/f (3.10/0.121/0.062); 5/f (1.62/0.146/0.055); 19/m
(0.003/-/-); -/- (0.016/-/-); 12/f (0.009/-/-); 4/m (0.032/0.005/0.004); 3/m
(0.033/0.003/0.001); -/f (0.017/0.001/-). PCB content in tissue generally increased from adult polar bears
to polar bear cubs and young, and polar bear milk contained high
concentrations of PCB. |
3. |
Samples of liver, kidney, and subcutaneous fat
from 24 polar bears from |
4. |
Liver
samples from 44 female and male polar bears, aged 3 to 29 years, from the
Canadian arctic archipelago were obtained during 1982-1984 to be analyzed for
organochlorines (Bandiera et al., 1997). The following are the mean
concentrations (ng/g lipid wt) in the liver samples: PCB 17459; PCB-138
3579; CB-153 7460; PCB-170 2279; PCB-180 4219; total
chlorinated benzenes 344; DDT 5078; chlordane 60031; dieldrin
6027. A positive correlation between cytochrome P450 1A and PCB levels
in the liver samples suggests that cytochrome P450 1A was induced in polar
bears by environmental exposure to PCBs. |
5. |
Polar bear liver and adipose tissue specimens from 121 bears collected in the Canadian Arctic and subarctic between 1982 and 1984 were analyzed for organochlorine compounds (Norstrom et al., 1988). The following are the average % of group in fat for identified organochlorines: total-PCB 0.5; PCB-47 0.5; PCB-99 8; PCB-118 0.5; PCB-146 1; PCB-153 42; PCB-137 1; PCB-138 11; PCB-187/182 0.5; PCB-183 1; PCB-156 1; PCB-157 0.5; PCB-180 17; PCB-170 11; PCB-194 4; PCB-206 1; technical chlordane (18,23) 3; U-1 4; nonachlor-III 16; trans-nonachlor 5; C-4 2; oxychlordane 63; heptachlor epoxide 7; pentachlorobenzene 25; hexachlorobenzene 75; DDT 19; DDE 81; α-HCH 71; β-HCH 29. The following are the mean concentrations (mg/kg lipid wt) of organochlorines in pooled adipose tissue lipid in polar bears listed by zone as (total-PCB/total-CHLOR/total-CBz/total-DDT/total-HCH/dieldrin): H1: 6/4.25/2.31/0.19/0.14/0.52/0.19; H2: 8/3.95/1.81/0.21/0.18/0.32/0.17; G: 8/8.25/3.42/0.26/0.28/0.30/0.21; E1: 6/6.63/3.81/0.27/0.12/0.31/0.30; E2: 16/4.43/3.68/0.23/0.22/0.79/0.50; F1: 18/5.94/3.72/0.25/0.30/0.62/0.53; F2:10/4.22/2.86/0.40/0.21/0.33/0.38; D1: 10/3.24/2.75/0.26/0.39/0.37/0.37; D2+D3: 20/4.25/2.73/0.25/0.41/0.36/0.34; C: 10/8.11/6.89/0.33/0.94/0.59/0.85; A1: 9/8.02/7.09/0.30/1.19/0.87/0.96. The correlation between organochlorine levels in pooled adipose tissue and mean levels in liver was highly significant for all organochlorines. |
6. |
Organochlorine concentrations were determined in the adipose tissue of 10 polar bears collected in Barrow Strait in 1982 and in 10 polar bears collected in Pond Inlet/north Baffin Island in 1984 (Muir et al., 1988). The following are the arithmetic mean concentrations (ng/kg wet wt) listed as (Admirality Inlet/Barrow Strait): total HCH 330/443; total Chlorobenzenes 446/337; total Chlordane 2971/2670; total DDT 210/213; dieldrin 375/381; total PCB 4572/4420; total Chlordane/PCB 0.66/0.61; total DDT/PCB 0.05/0.05; DDE/total DDT 0.78/0.70. |
7. |
Concentrations
of tris(4-chlorophenyl)-methanol (TCP methanol) and other organochlorines
were determined in blubber, liver, and kidney samples from polar bears
collected from Saint Lawrence River between 1983-1985 (Jarman et al., 1992).
The following are the mean concentrations (ng/g lipid wt) listed by location
as (tissue/N/TCPM/∑DDT/∑PCB/dieldrin): Churchill: (kidney/8/110/530000/18000/600),
(liver/1/6800/32000/94000/6700); |
8. |
Levels
of PCB methyl sulfones (MeSO2-CBs) and DDE methyl
sulfones (MeSO2-DDEs) were determined in blubber and liver tissues
from two polar bears from western Hudson Bay in 1985 (Bergman et al., 1994).
The following are the concentrations (µg/kg, extracted lipids) listed
as (blubber (polar bear 1/polar bear 2), liver (polar bear 1/polar bear 2): 3-MeSO2-2,5,2’,4’-tetra-CB (0.05/0.06, 0.3/0.3); 4-MeSO2-2,5,2’,4’-tetra-CB
(0.06/0.05, 0.4/0.3); 2-MeSO2-DDE (ND/ND, 0.9/0.6); 3-MeSO2-2,5,2’,4’,5’-penta-CB (0.09/0.1, 0.3/0.3); 4-MeSO2-2,5,2’,4’,5’-penta-CB (0.1/0.1, 0.2/0.2); 3-MeSO2-DDE
(ND/ND, 0.4/0.4); 3-MeSO2-2,5,2’,3’,4’-penta-CB (0.04/0.04, 0.6/0.5); 4-MeSO2-2,5,2’,3’,4’-penta-CB (0.1/0.1, 0.3/0.2); 3-MeSO2-2,5,2’,3’,4’,5’-hexa-CB (0.02/0.01, 0.1/0.1); 4-MeSO2-2,5,2’,3’,4’,5’-hexa-CB (0.02/0.02, 0.03/0.02); Total MeSO2-CB
(0.6/0.8, 3.0/2.7); Total MeSO2-DDE (ND/ND, 1.3/1.0); Total PCB
(15.0/16.7, 21.7/29.5); Total DDT (0.79/0.79, 2.26/2.33). |
9. |
Blood
samples from 90 adult female polar bears were collected from the Svalbard
area eastward to the |
10. |
Blood
samples from 90 adult female polar bears (age ≥5) were collected from
the Svalbard area eastward to the |
11. |
The
adipose tissue of a three-year-old female polar bear was collected at |
12. |
Polar
bear fat samples from 52 polar bears collected from Sanikiluaq, |
13. |
Male
polar bear adipose samples from 12 arctic and subarctic regions from the
Bering Sea to the PCB-49/3M-CB49 6.9/11.5/25.2/15.2/11.8/5.6/17.3/19.8/14.6/13.1/19.2/36.7; PCB-49/4M-CB49 6.6/12.9/26.8/16.9/12.5/6.8/15.2/20.2/13.8/12.5/18.3/34.8; PCB-64/4M-CB64 4.2/9.8/17.3/13.4/10.1/4.6/10.0/10.2/7.3/5.8/11.9/15.8; PCB-101/3M-CB101 21.3/23.1/42.3/29.4/22.4/19.6/39.5/67.8/47.2/35.6/35.7/81.9; PCB-101/4M-CB101 27.1/30.2/59.8/40.9/28.9/23.5/38.2/65.3/39.0/37.0/44.0/78.1; PCB-70/3M-CB70 3.2/6.8/10.6/6.7/5.0/1.9/6.5/11.5/6.7/5.3/7.8/15.8; PCB-70/4M-CB70 4.9/8.4/14.7/11.5/8.0/2.5/7.4/10.1/7.7/6.0/9.8/15.8; PCB-87/3M-CB87 10.3/17.7/40.1/24.8/19.4/11.0/27.9/51.6/23.1/18.8/28.9/61.3; PCB-87/4M-CB87 23.2/54.0/89.2/58.8/41.8/29.7/47.9/86.1/47.2/37.8/60.9/115.9; PCB-149/3M-CB149 1.9/4.9/7.5/4.1/3.7/1.5/4.5/11.7/6.0/3.9/7.6/18.8; PCB-149/4M-CB149 11.1/34.0/56.4/34.7/26.3/12.0/29.6/47.4/34.6/20.2/41.9/69.4; PCB-132/3M-CB132 1.2/6.6/4.5/2.4/1.6/1.3/2.8/5.8/3.0/2.5/4.1/12.7; PCB-132/4M-CB132 7.2/12.1/23.0/12.8/10.5/11.3/17.9/20.3/16.8/6.8/14.3/33.0; PCB-141/3M-CB141 4.4/5.2/8.9/4.0/5.3/5.5/11.0/20.0/8.2/5.3/8.4/16.8; PCB-141/4M-CB141 3.6/6.8/13.3/6.0/5.8/5.9/7.4/14.4/6.9/5.3/9.1/17.4; PCB-174/3M-CB174 0.8/0.9/1.5/0.9/0.7/1.2/1.4/4.0/2.5/1.3/1.3/3.6; PCB-174/4M-CB174 0.4/2.0/3.8/1.6/1.5/0.6/2.4/4.1/1.9/1.1/2.7/5.1; PCB-99
108.6/393.1/553.4/396.0/263.1/142.0/329.2/368.5/521.4/170.4/613.3/753.5; PCB-180
292.7/1126.8/1540.0/790.3/683.7/513.1/1011.0/2185.4/1667.1/869.1/1176.3/3411.8; PCB-149 0.0/1.6/3.3/1.9/0.0/2.0/2.2/3.3/2.1/3.5/3.1; S-MeSO2-PCBs
138.2/246.8/444.8/283.7/215.1/144.7/287.1/470.2/286.3/218.3/326.0/632.7; S-PCBs 1737/5396/6181/4595/3361/2529/4720/8863/7637/4280/6690/13730; 3-MeSO2-DDE 0.8/1.8/2.7/1.1/1.9/0.6/3.6/4.4/3.2/2.1/2.8/11.0; DDE 24.3/50.5/55.1/20.1/74.6/32.6/88.3/82.5/170.1/185.2/314.3/209.0. |
14. |
Adipose
tissue samples from polar bears were obtained between 1989-1993 from Wrangel
Island in |
15. |
Organochlorine
concentrations were determined in 6 polar bear milk samples from Svalbard ( |
16. |
Subcutaneous
tissue, blood, and milk were collected from polar bears
from |
17. |
Plasma,
blood cells, milk and subcutaneous fat samples were collected from polar
bears captured in the |
18. |
Blood
plasma samples from 56 polar bears captured in eastern |
19. |
Blood
plasma samples from 79 polar bears captured in eastern |
20. |
Blood
samples for PCB analyses were collected from 54 adult female polar
bears that were caught in the Barents Sea between Svalbard and |
21. |
Organochlorine
concentrations were determined in tissue samples from polar bears collected
in the vicinity of |
22. |
Polar
bear fat (N=7) and liver samples (N=13) were collected from male polar bears
(3-22 years of age) in the Resolute Bay area of the Canadian Arctic during
1992-1993 to be analyzed for organochlorines (Wiberg et al., 2000). The following are the mean concentrations (ng/g lipid wt) listed
as (fat/liver): (+)-trans-chlordane
0.20/7.3; (-)-trans-chlordane 0.02/2.3;
(+)-cis-chlordane 0.07/2.5;
(-)-cis-chlordane 0.02/2.0; octachlordanes ranged 3.6/18 to 29-190; nonachlordanes ranged 130/320 to 370/2000; trans-nonachlor
300/250; cis-nonachlor
n.a./n.a.; MC2 53/120; technical chlordane (33) 43/950; C-5
33/230; Unidentified clordane-2 40/245; Unidentified chlordane -3
100/28; Unidentified chlordane -4 7/500; heptachor-epoxide
300/2200; oxychlordane 1500/11000;
(+)-α-HCH400/440; (-)-α-HCH 190/130; β-HCH
130/69; γ-HCH n.a./n.a.; PCB-153 2700/7700. |
23. |
Liver
samples were collected from 16 adult male polar bears in the
Canadian arctic between 1992 and 1994 and analyzed for chlorinated
hydrocarbon contaminants and metabolites, determination of alkoxyresorufin O-dealkylase activities and
immunoquantitation of cytochrome P450 (CYP) protein levels (Letcher et
al., 1996). The following are the mean concentrations (ng/g lipid wt):
PCB-77 0.025; PCB -126 0.244; PCB -69 0.404;
2378-TnCDD 0.019; 12378-PnCDD 0.005; 123478-Hx CDD 0.002;
123678-HxCDD 0.002; 12346789-OCDD 0.004; 12478-PnCDF 0.002;
23478-PnCDF0.010; PCB -37 0.097; PCB -81 n.a.; PCB -105
52; CB-118 139; PCB -138
2331; PCB -170 1993; PCB -156 130; PCB -157 113; PCB -189
0.110; PCB -99 1660; PCB -153 7469; PCB -154 7; PCB -180
3340; PCB -183 159; PCB -194 559; S-MeSO2-PCB 1851;
S-3-MeSO2-PCB 1071; S-4-MeSO2-PCB 780; chlordane 30770;
DDT 951; Zolazepam 11; ∑PCB 18680. Total CYP
content was variable among bears and ranged between 1 and 2 nmol/mg
microsomal protein. The following activities are the mean concentrations
(pmol/min/mg): EROD 1165±454, PROD 21±7, BROD 185±59. BROD
activities did not exactly parallel PROD or EROD activities. CYP2B
content averaged 21.1±11.2 pmol/mg protein and was significantly greater than
the mean CYP1A content 4.9±3.4pmol/mg protein. CYP1A and CYP2B
were a more reliable measure of exposure to CHC inducers than
alkoxyresorufin O-dealkylase
activities in polar bear. |
24. |
Organochlorine concentrations were determined in free-ranging polar bears, categorized by age and sex before and after a fast averaging 56 days, from Churchill, Manitoba between 1992 and 1995 (Polischuk et al., 2002). The following are the mean organochlorine concentrations (µg/kg, lipid wt) in adipose tissue listed as (females with cubs-of-the-year (N=9) before fast, after fast/females with yearling cubs (N=7) before fast, after fast/cubs-of-the-year (N=12) before fast, after fast/yearling cubs (N=9) before fast, after fast/subadult and adult males (N=10) before fast, after fast): ∑-Chlorobenzenes
(105,143/116,149/239,261/177,224/149,186), ∑-HCHs
(171,183/177,182/249,201/197,229/240,146), ∑-CHLORs
(1835,2820/2406,2723/4717,6123/3506,4798/4145,2155), ∑-DDTs
(196,149/244,189/196,128/223,221/238,149), ∑-PCBs (2063,3163/2601,3476/4261,5508/3876,5158/3409,3975). The following are the means for the total body burden (mg) of organochlorines listed the same as above: ∑-
Chlorobenzenes (7,6/7,7/4,4/7,7/15,13), ∑-HCHs (12,9/10,8/4,3/8,8/25,10), ∑-CHLORs
(127,126/137,112/70,80/137,151/371,124), ∑-DDTs
(14,7/15,8/3,2/9,8/26,12), ∑-PCBs (142,140/150,152/62,71/150,160/277,247). The following are the mean animal
concentrations (µg/kg, whole body wt) of organochlorines listed the same as
above: ∑-
Chlorobenzenes (32,35/33,36/57,62/53,62/43,46), ∑-HCHs (52,46/49,43/59,48/60,65/65,36), ∑-CHLORs
(551,684/672,635/1074,1430/1024,1299/1048,501), ∑-DDTs
(60,38/69,45/48,31/67,62/70,37), ∑-PCBs (618,758/724,829/958,1276/1125,1389/847,911). |
25. |
Fat
samples were collected from 6 adult male polar bears from the Canadian high |
26. |
Organochlorine
residues were analyzed in the liver and adipose tissue of one mature polar
bear that was accidentally killed in |
27. |
Polar bear livers collected from northern
and western |
28. |
Between 1995-1998, samples were collected
from 121 male polar bears from the |
29. |
Between 1995-1998, samples were collected
from 121 male and 130 female polar bears from the |
30. |
Blood samples for organochlorine analysis
were collected from 86 adult female polar bears from Svalbard, Hopen,
Edgeoya, and the |
31. |
Concentrations of PCBs were
determined in two yearling sibling polar bears as well as their 11-yr-old
mother that were captured at |
32. |
Subcutaneous fat samples were taken from 5
polar bears collected near Barrow, |
33. |
Polar bear plasma samples collected from 30
polar bears captured in 1997 around the |
34. |
Concentrations of PCBs were
determined in two groups of female polar bears, females with cubs of the year
(FWCOY) and females without cubs of the year (FWOCOY), and within a group of
male polar bears collected from Svalbard, Norway between 1997-1998 (Braathen
et al., 2004). The following are the mean concentrations (ng/g wet wt)
of PCB congeners in plasma listed
as (FWCOY, N=17/FWOCOY, N=35/Males, N=29): PCB-99 9.01/8.50/7.41; PCB-118
0.23/0.31/0.33; PCB-153
41.1/37.8/34.6; PCB-156
1.22/1.05/1.10; PCB-180
27.6/24.8/23.0; PCB-194
4.91/5.42/6.19; ∑PCB5
83.9/77.6/72.3. |
35. |
During 1998-1999, blood samples from 26
polar bears (13 females and 13 males) from |
36. |
Persistent organochlorine contaminants were
determined in adipose tissue of 92 polar bears sampled between 1999-2001 in
central |
37. |
Organochlorine concentrations were
determined in the whole blood and adipose tissue of male (n=7) and female
(n=12) polar bears of random age (3-25 years) collected between
1999-2001 from central |
38. |
Adipose tissue from male (N=6) and female
(N=3) polar bears (>5 years old) from the |
39. |
Samples of polar bear livers (N=5) were
collected from the tissues archived by the U.S. Fish and Wildlife Service,
Anchorage, AK, and analyzed for organochlorines (Corsolini
et al., 2002). The mean concentrations (pg/g wet wt) for ∑PCNs, HCB,
DDE, and ∑PCBs were 370, 16, 13, and 2110, respectively. |
40. |
PBDE concentrations were analyzed in polar
bears captured in the |
II. |
Cholinesterase-Inhibiting Pesticides |
|
No data available |
III. |
Trace Elements, Metals, and Metalloids |
1. |
Fresh
(1977-1980) and preserved (museum) (1910-1927) polar bear hair samples taken
from polar bears across the Canadian Arctic were analyzed for Hg (Eaton and Farant, 1982). Mean
total Hg (µg/g) from the fresh
samples are as follows, listed by location: Amundsen Gulf (N=6),
18.54; |
2. |
Alaskan polar bear muscle and liver samples collected in 1972 were analyzed for total Hg (Lentfer and Galster, 1987). The following are the mean concentrations (µg/g wet wt) listed by tissue: Muscle (Western area, young, N=12 / Northern area, young, N=19 / Western area, adult, N=4 / Northern area, adult, N=11): 0.04 / 0.15 / 0.04 / 0.19; Liver (Western area, young, N=16 / Northern area, young, N=22 / Western area, adult, N=9 / Northern area, adult, N=15): 3.92 / 22.35 / 4.80 / 38.08. Bears north of Alaska had more Hg than bears west of Alaska, and the only difference between young and adult animals was in the northern area where adults had more Hg in liver tissue than young. |
3. |
A
total of 141 polar bear hair samples, collected from five Arctic areas during
1976-1988, were analyzed for estimation of Hg content (Renzoni and Norstrom, 1990). The five localities are:
A, western Hudson Bay, 1988, N=22; B, Beaufort Sea to |
4. |
Concentrations of total Hg were determined in hair of polar bears from captured from northwestern Greenland during 1978-1989, eastern Greenland during 1984-1989, and Svalbard during 1980 (Born et al., 1991). The following are the mean concentrations (µg/g dry wt) listed by location: Thule: (yearling, N=1 / 2 years and older, N=21) 9.51 / 8.38; Scoresby Sound (yearlings, N=3 / 2 years and older, N=37): 1.81/ 4.62; Ammassalik (2 years and older, N=4): 4.21; Svalbard (cub of the year, N=1 / yearling, N=1 / 2 years and older, N=29): 0.34 / 1.04 / 1.98. Concentrations of total Hg in hair were not found to be dependent on age or sex, however, there was a decreasing trend in Hg concentrations found from west to east. |
5. |
Samples
of liver, kidney, and subcutaneous fat from 24 polar bears from |
6. |
Polar
bear livers (N=67) from six zones in the western and central Canadian Arctic
in 1982 were analyzed for 22 elements (Norstrom et al., 1986). The following
are the mean concentrations (μg/g, wet wt): Ag 0.17; Al 0.23; As 0.07; Ba 0.02; Be 0.002; Ca 35.5; Cd 0.61; Co 0.3; Cr 0.10; Cu 38.6; Fe 168; Hg 30.1; K 2977; Mg 201; Mn 3.63; Mo 1; Na 844; Ni 0.3; P 3206; Se 10.0; Si 0.3-2.3; Sr 0.005-0.023; Th
0.05; Ti 0.02; V 0.07; Zn 62.4; Zr 0.3. Cd, Hg and Se had statistically significant
effects for age and geographical location. Average levels of Cd were significantly higher in the
eastern zones, while Hg levels
tended to be higher in the western zones bordering the |
7. |
Muscle,
liver, and kidney tissues from 38 polar bears caught in the |
8. |
Muscle,
liver, and kidney tissues from 100 polar bears, caught during 1983-1990 in
the Avanersuaq area, north-west Greenland, and Ittoqqortoormiit area,
central-east |
9. |
Levels of metals were determined in livers of
polar bears collected in 1984 in six zones in the Lancaster Sound, Baffin Bay
and Ca 82/109/107/112; 98/101; 136/125/134/136/161/129; Cd 1.22/1.03/0.60/0.58; 1.82/2.37; 3.96/3.13/4.57/3.85/2.70/3.33; Cu 102/120/85/81; 116/83; 114/109/126/146/94/121; Fe 344/305/274/489; 404/319; 846/476/359/448/464/417; Hg 122.5/99.8/200.3/58.9; 64.2/66.9; 84.2/43.4/21.9/53.2/18.5/20.0; K 7124/8101/8349/8294; 8633/8789; 9263/8664/9765/9244/8587/8147; Mg 481/555/579/599; 587/609; 671/676/711/666/599/595; Mn 12.0/9.6/9.9/8.2; 10.0/10.4; 10.9/13.8/12.1/14.0/10.7/12.0; Na 1535/2527/2379/3227; 2173/2373; 3155/3230/2720/2661/3330/2806; P 8541/8848/9203/9749; 9354/9688; 10716/10532/11658/10873/10747/10120; Se 54.1/32.7/63.4/23.6; 21.9/24.9; 26.6/14.5/9.7/19.4/3.9/4.7; Zn 172/188/141/142; 176/176; 205/205/211/221/178/180. Only levels of Cu, K, and Zn were found to have no statistically significant differences among zones. Levels of Cd, Hg, and Se were positively correlated with age, whereas K, Mn, Mg, and P were negatively correlated with age. Fe was significantly higher in females than in males. |
10. |
Concentrations
of total and organic Hg were
analyzed for polar bears collected from |
11. |
Polar
bears from |
12. |
Bone tissue from 78 polar bears from the Canadian Northwest Territories was analyzed for various elements (Golovkin et al., 1991). The following are the mean concentrations (in conventional units) for 4 groups (grouped by location) listed as (group 1, N=6/ group 2, N=37/ group 3, N=23/ group 4, N=12): P 1.36/1.55/1.52/1.48; Ca 112/119/119/115; Fe 0.59/0.7/0.74/0.51; Zn 4.30/4.76/5.35/5.5; Sr 49/39/47/57. |
13. |
Tissue
samples from polar bears captured from the region of |
14. |
Concentrations
of twelve essential and non-essential elements were evaluated in tissues of
polar bears of arctic Alaska (USA) collected between 1995-1997 (Woshner et
al., 2001). Concentrations (µg/g wet wt) in the liver (N=24) are as follows: As 0.09, Cd 0.47, Cu 30.0, Pb 0.08, Mg 371.0, Mn 5.13, Se 9.33, Ag 0.17, Zn 78.64, HgII 13.21, MHg 0.49, total Hg 14.22.
Concentrations in the kidney (N=24) are as follows: As 0.02, Cd 8.69, Cu 3.39, Pb 0.29, Mg 247.0, Mn 1.80, Se 12.99, Ag 0.01, Zn 39.60, HgII not analyzed (n.a.),
MHg n.a., ΣHg n.a..
Concentrations in the muscle (N=23) are as follows: As ND (N=18), Cd 0.01
(N=18), Cu 2.97, Pb 0.02, Mg 495.3, Mn 0.28, Se 0.54, |
IV. |
Petroleum |
|
No data available |
V. |
Other |
1. |
Liver tissues of 17 polar bears from |
Polar Bear Contaminant Response Data |
|
I. |
Organochlorine Contaminants |
|
Concentrations of PCBs, thyroid
hormones (THs), and retinol were
determined in two groups of female polar bears, females with cubs of the year
(FWCOY) and females without cubs of the year (FWOCOY), and within a group of
male polar bears collected from Svalbard, Norway between 1997-1998 (Braathen et al., 2004).
The following are the mean concentrations of THs (nmol/L) and retinol (µg/L) in the plasma of the polar bears
listed as (FWCOY/FWOCOY/Males): Total T4
N=9, 15.3/N=30,18.5/N=22,13.5; Free T4
N=11, 4.38/N=28, 5.20/N=23, 3.46; Total
T3 N=14, 1.26/N=28, 1.58/N=21, 1.23; Free
T3 N=6, 1.26/N=16, 1.42/N=11, 0.95; Retinol
N=17, 181/N=22, 201/N=15, 183. PCBs
did not affect the retinol status in any of the three groups. PCBs affected five TH variables in
the female polar bears (Total T4, Free T4, Free T3,Total
T3:FT3, Total T4:Total T3), while they affected only two TH variables in
males (Free T3, Free T4:Free T3). |
II. |
Cholinesterase-Inhibiting Pesticides |
|
No response data available |
III. |
Trace Elements, Metals, and Metalloids |
|
No response data available |
IV. |
Petroleum |
1. |
Three sub-adult polar bears that were captured as nuisance bears in the area of Churchill, Manitoba in 1979 were immersed in a mixture of sea water and oil to determine body temperature, metabolism, and whole body thermal conductance before and after oil exposure (Hurst et al., 1991). Prior to oil exposure, grooming averaged 5% of the study animals’ time, but in the first 6 h following oil exposure increased to 42%. Within 8 h of exposure, violent shivering occurred in all 3 bears and continued for 36 more hours. Metabolism measured after oil exposure showed a significant average increase of 57% over pre-oil values. The following are the temperatures (°C) determined for the bears listed as (before oil contact/after oil contact): body temperature: bear 2 (36.9/36.9), bear 3 (36.8/35.8), bear 4 (36.6/36.7), mean (36.8/36.5); skin temperature: bear 2 (36.4/37.3), bear 3 (34.9/35.7), bear 4 (32.9/34.0), mean (34.7/35.7); whole body thermal conductance: bear 1 (1.55/1.86), bear 2 (2.22/3.08), bear 3 (1.56/2.50). There was a significant increase in skin temperature for all animals following oil exposure with an average increment of 0.96 °C. |
2. |
Three young polar bears that had been trapped as nuisance animals in the Churchill area in 1980 were immersed in a mixture of sea water and crude oil and subjected to a wind tunnel to simulate Arctic conditions, in order to test the physiological effects of a simulated oil slick on polar bears in view of the possibility of an oil spill due to explorations and drilling operations in the north (Crawshaw, 1980). The polar bears were washed 17 days later, but subsequently became anorectic and progressively more depressed. One male bear died 25 days after immersion. A second male bear, which exhibited severe depression and head tremors, had euthanasia performed on it. The third bear, a two-year-old female, was anesthetized to examine 33 days after immersion after she had not eaten for 20 days and was exceptionally docile. Examination revealed that the bear was extremely thin (180 lbs.), dehydrated, and anemic. The coat was in poor condition. There was no evidence of neurological disorder and temperature, pulse and respiration were normal. Urine was passes in small quantities and was dark and contained blood and a little protein. Blood samples confirmed the presence of anemia and gave evidence of renal failure with associated serum electrolyte abnormalities and some liver dysfunction. Symptoms gradually alleviated. After many more times of being anesthetized and worked on, she began to slowly start drinking again and eaten again. She had problems with abscesses opening and weakness in her legs, but eventually overcame this as well. About six months after the oil immersion, the bear was recovered and appeared to be in excellent condition, weighing 411 lbs. |
3. |
Fur
samples from the mid-back region were obtained from 3 subadult polar bears
taken during October in northern |
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