The Davis Strait - DCE - Nationalt Center for Miljø og Energi

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Limited data are available to determine whether species adapted to cold are
more (or less) sensitive to contaminants than temperate species and thereby
whether the relationships between contaminant concentrations and impacts
derived from temperate species can be applied to the sub and high Arctic
environment. As part of the AMAP assessment in 2009, the most recent studies
have been reviewed and summarised in regard to biological effects and
how they relate to organohalogen contaminant (OHC) exposure (Letcher et
al. 2010). First attempts have been made to assess known tissue/body compartment
concentration data in the context of possible threshold levels on
top trophic level species, including seabirds (e.g. glaucous gull), polar bears
and Arctic char.
There was only little evidence that OHCs are having a widespread effect on
the health of Arctic organisms. However, on a smaller scale, effects have
been documented. Based on the ‘weight of evidence’ found in different studies
performed on Arctic and Sub-Arctic wildlife and fish, several key species
and populations have been identified (Letcher et al. 2010). Among these are
East Greenland polar bear and ringed seal, Greenland shark from the Baffin
Bay/David Strait and a few populations of freshwater Arctic char.
Pollution effects have also been investigated on polar bears (Ursus maritimus)
in more detail, since this species exhibits the highest levels of certain contaminants
(e.g. organochlorines, PBDEs, PFCs or mercury) in the Arctic, in
particular the populations from East Greenland and Svalbard (Norway). Effects
on polar bear health caused by the complex, biomagnified mixture of
these substances are summarised and assessed by Sonne (2010). The review
shows that hormone and vitamin concentrations, liver, kidney and thyroid
gland morphology as well as reproductive and immune systems of polar
bears are likely to be influenced by contaminant exposure.
7.3.1 Polyaromatic Hydrocarbons (PAH) and possible effects on biota
At present, PAH levels are relatively low in Greenland biota; although, as
described in the previous section, point sources in harbour areas are found.
With intensification of human activities, e.g. in relation to oil exploration,
however, this may change and reliable environmental monitoring tools are
required to identify any potential impact on the biota.
PAHs are taken up by marine organisms directly from the water (via the
body surface or gills) or through the diet. Many studies have indicated that
PAHs are more or less metabolised by invertebrates and generally efficiently
metabolised by vertebrates such as fish (Hylland et al. 2006). Therefore, and
in contrast to most persistent organic pollutants, PAHs are not biomagnified
in the marine food web. Dietary exposure to PAHs may, however, be high in
species that preferentially feed on organisms with low ability to metabolise
PAHs, such as bivalves (Peterson et al. 2003). At the other end of the food
chain, filter-feeding zooplankton can be exposed to high levels through filtering
of oil droplets containing PAHs from the surrounding water.
The effects of PAHs on organisms are extensive and occur on various levels,
including biochemical and physiological and/or genotoxic (Hylland et al.
2006). The responses and tolerance to PAHs can vary considerably in organisms,
depending on the geographical range of the species but also on the
particular PAH mixture. PAHs are a large group of diverse substances, ranging
from two-ring naphthalenes and naphthalene derivates to complex ring