Marine områder 2011 - DCE - Nationalt Center for Miljø og Energi

Registrations from the Great Belt and Kalundborg Fjord showed that the
porpoises are present all year round, but that the abundance is highest in
the Great Belt during summer and in Kalundborg Fjord during winter. In
addition, there was a distinct diurnal variation in sound signals with
most detection during night and fewest during daytime.
Hazardous substances and biological effects
In 20 % of the common mussel samples and 86 % of the fish samples the
content of heavy metals were higher than Environmental Quality Standards
for biota (EQS) due to mercury (Hg) but no metals were above the
EU criteria for content in food. Only the content of nickel (Ni) and copper
(Cu) in the soft clams Mya arenaria from Ringkøbing Fjord were above the
‘good ecological status’ limit according to Norwegian assessment criteria.
Concentrations of metals in seawater from Skive Fjord in 2010/2011 were
within the EU limits for nickel (Ni), lead (Pb), and cadmium (Cd).
The content of TBT in mussels is decreasing in the areas where time
trends of significance are available due to the ban of antifouling paints.
However, at more than 50 % of the stations, the concentrations are still
above the ecotoxicological assessment criteria (EAC) so an impact from
TBT in the marine environment can still be expected.
PAH in mussels were not above the EAC and in most cases corresponding
to or below the ‘background’ criteria for the North Sea.
Chlorinated compounds in fish were generally below the EAC except for
CB118 (50 % of fish above EAC) and HCB (25 % of fish above EAC), and
also CB138 were above EAC in a few samples. Thus it cannot be ruled out
that CB118 and HCB still have an impact in the marine environment.
It is possible to identify the geographic origin of flounder based on the
composition of chlorinated compounds.
Time trends for hazardous compounds are in general decreasing especially
for the organic compounds under regulation (PCB, and TBT) –
most evident in Langerak (the Limfjord).
Imposex and intersex in sea snails due to exposure to TBT are still widespread
and assessed as an environmental problem in Danish marine waters.
Based on the OSPAR criteria for imposex and intersex, good ecological
status is only found in the North Sea and the Skagerrak.
Levels of imposex and intersex are so high in the inner Danish marine
waters that in relation to OSPAR and HELCOM criteria many areas have
to be considered as not acceptable and even bad in certain contaminated
harbours and marinas. However, the level has decreased markedly in recent
years, which indicates that further improvements can be expected.
Investigations of lysosomal membrane stability in common mussels indicated
that approximately one third of the investigated coastal areas were
affected by hazardous substances and especially PAH.
Investigations of eelpout showed marked differences in the degree of effects
between areas, both concerning presence of malformation in fry,
CYP1A enzyme activity, and PAH metabolites in the gall. A correlation
between the activity of CYP1A and the concentration of PAH and PCB
was found, whereas this was not the case for malformation in fry and the
measured hazardous substances.
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