General development
trends for nitrogen and phosphorus in surface
water
Taking into account climatic conditions,
generally no significant changes have occurred
in the input of nutrients from point sources
and agriculture to the aquatic environment
during the past 6 years. Variations in precipitation
imply marked inter-annual fluctuations in
the input from both point sources and agriculture.
As the amount of precipitation in 2009 was
below normal and smaller than in both 2007
and 2008, the runoff of nitrogen and phosphorus
to the sea was correspondingly lower.
Groundwater
The efforts implemented with the introduction
of the Action Plan on the Aquatic Environment
I in 1987 – with the aim to reduce the runoff
of nitrate from cultivated soils – have
led to declining concentrations of nitrate
in the oxygenated young groundwater. The
same tendency cannot be traced for oxygenated
‘old’ groundwater, defined as groundwater
older than 25 years. The frequency of exceedance
of the threshold value for the concentrations
of nitrate in drinking water shows a clear
declining tendency owing to the fact that
wells with too high nitrate concentrations
are closed and replaced by deeper wells.
The frequency of pesticide occurrence in
groundwater was 40% in 2009, which is similar
to recent preceding years.
Lakes
Investigation of fish stocks in lakes has
been included in the aquatic monitoring
programme with varying frequency. It is
now possible to conduct the first comparative
analyses over time of the development of
the fish stock. Overall, a modest improvement
can be traced in the composition of the
fish stock of the monitoring lakes. The
improvements mean that predatory fish account
for a higher proportion of the biomass in
the lakes. The improvements of the fish
stock correspond with the other improvements
recorded in the lakes during the period
11000-2009, such as reduced nutrient input
and larger Secchi depth.
Air
Air monitoring during the period 11000-2009
has shown that the input of nitrogen from
the air to nature and aquatic areas has
declined during the period, exhibiting,
however, between-year variations depending
on meteorological conditions. Overall, the
transfer of nitrogen from air to nature
and aquatic areas, including marine areas,
has declined by approx. 30%. The decline
can be ascribed to a reduction of both international
and Danish sources.
Facts on NOVANA
The National Monitoring Programme for Aquatic
Areas and Nature (NOVANA) was implemented
on 1 January 2004. Since 1988 Denmark has
had a nationwide monitoring programme for
aquatic areas. The programme is based on
the “Aquatic Environment Plan” from 1987,
introducing monitoring of the aquatic environment
with emphasis on water chemical conditions
in the sea, estuarine areas, lakes, streams
and groundwater, as well as on significant
sources of pollution such as sewage, agriculture
and airborne pollution. Since the start,
pesticides and other environmentally hazardous
substances have been included in the monitoring
of groundwater, and since 1998 in the remaining
parts of the programme as well.
With the implementation
of NOVANA as an integrated monitoring programme
for the aquatic environment, air environment
and terrestrial nature, Denmark has since
2004 had a complete and systematic monitoring
of both the aquatic and the terrestrial
nature and environment. The monitoring stations
are distributed over the whole country.
