The natural phosphorus load exceeds Sweden’s emissions target. This is revealed in a new report based on the hitherto most accurate mapping of Sweden's emissions of eutrophic substances into the Baltic and North Seas. Of a total of 780 tonnes of phosphorus that reaches the Baltic each year, 370 tonnes is due to natural leakage.
– A lot of work lies behind these results. We have surveyed the entire Swedish land areal, and calculated the runoff from virtually every field, urban and forested area, says Helene Ejhed at IVL Swedish Environmental Research Institute, project leader for the survey.
The study has been carried out by the Swedish Environmental Emissions Data Consortium, SMED, on behalf of the Swedish Marine and Water Agency.
Findings show that most of the nitrogen and phosphorus reaching the Baltic and North Seas from Sweden and is a result of human agency, comes from agriculture, wastewater treatment plants, atmospheric deposition (nitrogen), industries and small sewage plants. The researchers estimate that the load from stormwater drains and small outlets is more significant than before.
But scientists are most concerned about the revelation that natural emissions of phosphorus to the Baltic – those that occur without human agency through natural decomposition processes in the environment – are higher than Sweden's emissions cap. According to the Baltic Sea Action Plan, phosphorous emissions in Sweden should not exceed 308 tonnes – however, the survey shows that natural leaching accounts for 370 tonnes.
– This means that the phosphorus target for the Baltic Proper (the part of the Baltic Sea from Åland Sea to the Danish sounds) is very difficult to achieve due to the natural background load, and also demonstrates the magnitude of the challenge posed by the phosphorus emissions target, says Helene Ejhed.
Some of the measures to reduce phosphorus emissions in Sweden may prove very expensive, and there is still a great deal to be done in other countries around the Baltic Sea.
– We have much to do if we are to cut back emissions in Sweden, but the results of this study shows how important it is that we adopt an overarching perspective, so that we apply the right measures in the right places, says Helene Ejhed.
In Sweden, for example, this means creating wetlands to capture nutrients and implementing measures in other ocean basins to promote a better environment in the Baltic Proper, she observes.
For more information, please contact: Helene Ejhed, email@example.com, +46 (0)10-788 65 46
The study has been carried out on behalf of the Swedish Marine and Water Agency by SMED, the Swedish Environmental Emissions Data Consortium – a collaboration platform between IVL Swedish Environmental Research Institute, Statistics Sweden, the Swedish University of Agricultural Sciences and the Swedish Meteorological and Hydrological Institute.