Jung-Madsen, S., Boutrup, I.K., Fredshavn, J., Hansen, A.S., Nielsen, V.V., Svendsen, L.M., Blicher-Mathiesen, G., Thodsen, H., Hansen, J.W., Høgslund, S., Johansson, Nielsen, R.D., Holm, T.H., Kjær, C., Ellermann, T., Thorling, L. &, Frank-Gopolos, T. 2023. Vandmiljø og Natur 2021. NOVANA. Tilstand og udvikling - faglig sammenfatning. Aarhus Universitet, DCE – Nationalt Center for Miljø og Energi, 72 s. - Videnskabelig rapport nr. 532 http://dce2.au.dk/pub/SR532.pdf
For the sake of clarity, the summary is very brief. This means that the underlying basis for data and reservations, e.g. in relation to uncertainties of results or specific conditions in a single year, are not included, but can be found in the scientific background reports. It is therefore necessary to consult these scientific reports if, for example, the results are to be used in a decision-making process.
Since 1990, there has been a significant reduction in the content of nitrogen in the surface water environment in general. This generally correlates well with a reduction in the sources, listed here as the development in fertiliser use and emissions from wastewater treatment plants. The nitrogen surplus (nitrogen added to the field minus nitrogen removed through harvesting) was in 2021 slightly lower than in 2020, primarily due to a lower allocation of nitrogen with the fertiliser. A possible effect of changes in the nitrogen surplus on the leaching of nitrogen depends on a number of factors, including catch crops.
In 2021, the total nitrogen input from soil to sea was approximately 49,000 tons N. This is a decline compared to 2020, where the nitrogen input was calculated at 56,000 tons N. The lower nitrogen input in 2021 is due in particular to the lower water runoff in 2021, but may also be affected by the lower nitrogen surplus in the fields in 2021.
If the year-to-year variations in the runoff (flow normalised input) are taken into account, the input in 2021 was approx. 55,000 tons N, where it was 51,000 tons in 2020.
Flow normalised nitrogen input from land to sea has been reduced by approx. 42% since 1990, but has overall been at the same level over the past approx. 10 years, albeit with a relatively low input in 2018 followed by a high input in 2019 and a relatively low input again in 2020 - a pattern which has been assessed to be particularly attributable to the special weather conditions in these three years and the derived effects on the agricultural sector.
Since 1989, there has been a significant reduction in the phosphorus content in fresh and coastal surface waters, which is mainly driven by improved wastewater treatment – primarily at the large wastewater treatment plants and separate industrial emitters – approx. up to the year 2000. There has been no significant development in phosphorus input seen over the past approximate 20 years. For watercourses, the concentration of total phosphorus has decreased by almost 33% during the period, while the phosphorus input to the sea has been reduced by about 69% and has been calculated to 1,600 tons phosphorus in 2021.
Metals and organic environmentally hazardous substances
This year's reporting includes data from measurements in air, marine areas, watercourses, lakes and groundwater.
There has been a significant decrease in the input of metals from precipitation to surface water from 1989 up to around the millennium. For the past 15 years, the input has only decreased slightly compared to previous years.
Fluorinated compounds, including PFOS, are among the organic environmentally hazardous substances included in the monitoring. PFOS was detected in all examined liver samples from fish in marine areas and watercourses. Environmental quality requirements have been set for PFOS in fish muscles, and taking into account that the measurements were carried out on fish livers, concentrations above the environmental quality requirement were not found.
In 2021, limit and target values were not exceeded for pollutant components covered by the EU’s air quality directives. For the vast majority, air concentrations decreased, which is generally consistent with the development in emissions. However, for a few of the air pollution components no decrease was found, e.g. for ozone and copper, but the threshold value requiring that the public be informed about high ozone levels (180 µg/m3 as the hourly average value) was not exceeded.
Nonetheless, if the concentrations for 2021 are compared to the new guidelines for air quality from WHO from 2021, concentrations are above the guidelines for all air pollution components - with the highest exceedance for PM2.5 and nitrogen dioxide. For air pollutants with guidelines for short-term exposure, it is seen that the concentrations are above the guidelines from WHO for PM2.5, PM10, nitrogen dioxide and ozone. On the other hand, the levels for sulphur dioxide and carbon monoxide are clearly below the new guidelines.
Calculations on the health effects of the total air pollution in Denmark show about 3,900 premature deaths in 2021. The total external costs related to air pollution in Denmark were estimated at around DKK 63 billion in 2021, which is which is slightly above the average for the period 2019-2021.
In the groundwater monitoring in 2021, a nitrate content above the quality requirement (50 mg/l) was measured in 13% of the intakes studied. This corresponds to the level in the five-year period 2017-2021, when this was the case in 15% of the tested intakes.
In the study of pesticides, monitoring in 2021 found one or more pesticides or degradation products from pesticides in 59% of the studied intake. In 26% of the intakes, concentration measurements were above the quality requirement 0.1 μg/l at least once. In the period 2019-2021, when virtually all active intakes were sampled at least once, pesticides or degradation products were detected in 65% of the intakes and measurements were above the quality requirement at least once in 32% of the intakes. The three most frequently identified substances in 2021 were DPC (Despheryl Chloridazon), DMS (Dimethylsulfamid) and 1, 2, 4 triazole.
When studying organic micro-pollution in groundwater in the period 2017-2021, one or more PFAS compounds were found in 18% of the intakes studied. In 0.3% of the studied intakes, concentrations above the requirement value were measured for the sum of 12 PFAS compounds, while concentrations above the requirement value for the sum of 4 PFAS compounds were measured in 6% of the studied intakes.
The results of the monitoring of the condition of the lakes show that since 1989, significant improvements have been made to a number of the key parameters that indicate something about the state of the lake. Overall, the nutrient concentration has been significantly reduced, chlorophyll a concentration (a measure of the amount of algae) has been reduced and Secchi depth in the lakes has increased. If, rather than looking at the entire period from 1989-2021, you compare the monitoring results from the past two six-year periods, it can, however, be ascertained that the levels of nutrients and chlorophyll have generally increased between these two periods, which indicates that the positive development in the lakes has, at best, stagnated.
In 2021, the extent of oxygen depletion in mid-September was the sixth largest since 2002, and since 2008 it has only been surpassed in 2016 and 2020. Nearly half of the oxygen-depleted area showed marked oxygen depletion. The extent of oxygen depletion in September has increased significantly since 2010. A significant part of the variation in the extent of oxygen depletion is due to weather conditions (primarily wind and temperature). However, nutrient supply is a fundamental factor in the development of widespread oxygen depletion.
Algae growth was among the lowest measured during the monitoring period and the water was clearer than usual. The good conditions in 2021 are due to low runoff of freshwater and, thus, low nutrient supply from autumn 2020 and over the winter. In general, the state of the environment in the water column has deteriorated, with higher chlorophyll content and more unclear water since 2012.
Observations of eel grass in 2021 showed an improvement in the fjords and status quo in coastal waters and the Limfjord compared to 2020. Over the past ten years, an otherwise positive development has stagnated and, in some areas, has been reversed, which is also the case for macroalgae.
In the open inner waters, the species composition of the bottom fauna shows that generally there are no problems associated with eutrophication in relation to the bottom fauna, but in some areas there are negative effects of physical disturbance. Monitoring of the bottom fauna in the North Sea indicates that the communities here are also affected by physical disturbance. Critical oxygen conditions caused poor conditions for the bottom fauna in some of the study areas in fjords and coastal waters.
For seals, the number of harbour seals has grown to a stable level since their conservation in the 1970s, while grey seals breed to a very limited extent. More porpoises have been counted in the Skagerrak than in 2020, but generally there is a decline in the number of porpoises in the inland waters.
Over the entire period of the monitoring programme, there has been a positive development in the environmental state of the sea as a result of a significant reduction in nutrient inputs. However, this development has stagnated or even declined over the past approx. 10 years for a number of parameters. Overall, the development in recent years has shown that Danish waters are still very vulnerable to pressures and are still far from the goal of a stable good environmental condition.
In 2021, the NOVANA monitoring of habitat species included a total of 34 species of mammals, reptiles and amphibians, vascular plants and mosses, as well as a single arthropod on appendices II and IV of the HABITAT directive. The species include beaver, 17 species of bats, field lizard, nine amphibian species, four species of vascular plants, the moss species slender green feather-moss as well as the insect large white-faced darter.
Of the 46 breeding bird species in NOVANA, 42 species were monitored in the Intensive 1 and Intensive 2 programme, respectively, in 2020-2021. In addition, the cormorant is monitored in a special programme. The Intensive 1 programme includes species that are found in, or return to, known locations. Of the 34 species in the Intensive 1 programme, 8 species have shown declining populations, 11 species have remained stable, while another 13 species have experienced increasing populations. Two species have disappeared as breeding birds in the NOVANA period 2004-2021. The Intensive 2 programme primarily covers rare or irregularly breeding species. Here, seven out of 11 species have increasing populations, two species have stable populations and two species have disappeared in the NOVANA period 2004-2021.
68 species of migratory birds are monitored, including 45 species at the nationwide mid-winter census in 2020. The majority of the species have stable or fluctuating populations or are increasing, both in the past 10-12 years and in the long period since the counts began (in the late 60s or beginning of the 80s, depending on the species). Many wintering waterfowl, swimming ducks and waders appear in highly fluctuating numbers, depending on the severeness of the winter, with low numbers in cold winters and high numbers in mild winters.
