Miljøfremmede stoffer og tungmetaller i vandmiljøet - Danmarks ...

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Summary
The Danish Nationwide Monitoring and Assessment Programme for
the Aquatic Environment (NOVA-2003) run over the period 1998-
2003. The programme monitored the air, wastewater treatment plants
and other point sources, agricultural catchments, the groundwater,
watercourses, lakes and marine waters. The Danish monitoring programme
was established in 1987 in order to follow development in
the aquatic environment and record the effects of the reduction in
discharges. In 1998 monitoring of hazardous substances and heavy
metals was added to the programme. The monitoring results were
reported yearly and the present report gives an overview of the results
for the entire period.
The overall picture shows that hazardous substances and heavy metals
are generally found in low concentrations and with no environmental
significance. The monitoring results have further documented
that some areas are impacted or the Danish permitted limits or quality
criteria have been exceeded.
Pesticides found most frequently in groundwater and fresh surface
water
Pesticides were found in groundwater and fresh surface water while
other organic hazardous substances were hardly present. Pesticides
were found more frequently in lakes than in watercourses, but concentrations
were generally lower in the lakes than in the watercourses.
Accumulation in the marine environment
Among the organic hazardous substances only pesticides occurred in
a few cases in watercourses and lakes. Even the substances which
were found most often in outlets from wastewater treatment plants or
substances discharged in large amounts were found in only a few
samples from watercourses and lakes. This applies, for example, to
the softener DEHP.
A number of substances were found in sediment, mussels and fish
from marine areas. It was typically slowly degradable and accumulative
substances such as DEHP, which were found widely in sediment
in fjords and coastal areas. Some of the substances which occurred in
sediment, mussels and fish are not used in Denmark any longer. DDT
is one example. Some of the substances occurred in such high concentration
that they may pose an environmental risk.
Heavy metals in the aquatic environment
The amount of heavy metals transported to inland areas and surface
waters has been decreasing since the 1990s. In 2003 heavy metal concentrations
in fresh surface waters were low compared to the Danish
quality criteria, while most metals in marine areas were found in concentrations
exceeding the level described by the OSPAR quality crite-