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

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7 Contaminants, background levels and effects
Doris Schiedek (AU)
Knowledge on background levels of contaminants in areas where hydrocarbon
exploration and exploitation are foreseen is important, since it serves as
a baseline for monitoring and assessment of potential future contamination
of the environment caused by these activities. The occurrence of contaminants
in the marine environment and their potential impacts on biota has
been studied in Greenland over the years in various regions and with different
purposes. An overview is given in Boertmann et al. (2009). In the following,
present knowledge is summarised with focus on studies with relevance
for the Davis Strait assessment area.
Baseline data on lead, cadmium, mercury and selenium levels in molluscs,
crustaceans, fish, seabirds, seals, walruses, whales and polar bears have been
compiled for different geographical regions, including West, Northwest and
Central West Greenland (Dietz et al. 1996). Only data for animals not affected
by local pollution sources, i.e. former mine sites are included. The overall
conclusion was that lead levels in marine organisms from Greenland were
low, whereas cadmium, mercury and selenium levels were high, in some
cases exceeding Danish food standard limits. No clear conclusions could be
drawn in relation to geographical differences concerning lead, mercury and
selenium concentrations. In general, cadmium levels were higher in biota
from Northwest Greenland compared with southern areas.
7.1 AMAP Monitoring Activities
With 1991 as baseline, the Arctic Monitoring and Assessment Programme
(AMAP) was established to monitor identified pollution risks and their impacts
on Arctic ecosystems. The Arctic is a region with almost no industry or
agriculture. Most of the persistent organic pollutants (POPs) and a substantial
number of the metals (e.g. mercury) found in the Arctic environment are
of anthropogenic origin. The POPs, mercury and other substances have
reached the Arctic as a result of long-range transport by air and via oceans
and rivers (AMAP 2004). Once in the Arctic, contaminants can be taken up
in the lipid rich Arctic marine food web. In general, the level of mercury has
increased in the Arctic, with implications for the health of humans and wildlife.
There is also some evidence that the Arctic is a ‘sink’ for global atmospheric
mercury (Outridge et al. 2008).
As part of AMAP activities a biological time trend programme was set up in
Greenland with focus on a suite of POPs, including PCBs (Polychlorinated
Biphenyls) and different trace metals, e.g. cadmium (Cd), mercury (Hg), selenium
(Se). A detailed overview of contaminant levels and temporal trends
in the monitored species is given by Schiedek in (Boertmann & Mosbech
2011), which included results from the latest AMAP assessment in 2009
(Muir & de Wit 2010).
In general it can be stated with regard to POPs that the AMAP assessments
have revealed levels of organochlorines in Arctic biota generally to be highest
in marine organisms belonging to the top trophic level (e.g., great skuas,