Organohalogen concentrations and a gross and histologic ...

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al.,1993). Hepatic changes associated with high environmental levels of organohalogens
have only been investigated in cormorants (Phalacrocorax
carbo) (Fabczak et al., 2000) and fish (Abramis brama) (Koponen et al., 2001)
and such associations has not been studied in marine mammals.
In laboratory animals like rats and mink, several acute studies of PCBs have
associated these compounds with hepato-toxicity due to the portal vein
transport and high metabolic capacity of it’s parenchymal tissue (e.g. Kimbrough
et al., 1971, Bruckner et al., 1974, Jonsson et al., 1981, Bergman et al.,
1992, Chu et al., 1994, MacLachlan and Cullen 1995, Parkinson 1996). Specifically
in the liver, acute organohalogen compound toxicity is mediated
through subcellular toxicity (impaired ATP synthesis, protein synthesis a.o.)
(Parkinson 1996) while chronic exposure may affect endocrine homeostasis
via upregulation of CYP-isozymes (e.g. 1A and 1B) (e.g. Boon et al., 1992,
Wong et al., 1992, Lin et al., 2003, van Duursen et al., 2003).
In Arctic marine wildlife, polar bears (Ursus maritimus) from East Greenland
are among those polar bears carrying the highest levels of organohalogens
and in some individuals, the levels are in the range that are suspected to negatively
affect reproduction and survival in seals from the Baltic Sea (de
March et al., 1998, AMAP 2004). Liver tissue, subcutaneous fat and skulls
were collected from the East Greenland subsistence hunt of polar bears during
1999-2002. The purpose was to study if there was a correspondance
between histopathological changes, in the liver and known specific organohalogen
induced changes and if there was a correlation between these
and individual levels of organohalogens.
Materials and Methods
Hepatic tissue (n=88) and skulls (n=44) from East Greenland polar bears
from the areas between Skjoldungen at 63º15’N and Danmarks Havn at ca.
76º50’N were sampled 1999-2002 by greenland subsistence hunters and deposited
at the Zoological Museum in Copenhagen, Denmark. All samples
were taken