Emissions of metals

Cadmium


The total load of cadmium to water is about 4 400 kg/year. Leaching from forests, atmospheric deposition on lakes and stormwater are the most important diffuse emissions.
Emissions from point sources (wastewater treatment plants and industries) contribute to approximately 14 % of the total load, with industries as the most important source, see figure 1.

Figure 1. Annual load of cadmium to water divided by source. 
Figure 1. Annual load of cadmium to water divided by source.


The contribution of each emission source to the load of cadmium varies between the river basin districts, see figure 2. The contribution from stormwater is of greater importance in the southern water districts whereas leaching from other land (mire areas, mountain areas and open land) contributes to a greater extent to the total load in the northern districts. Forests stand for about the same percentage within each river basin district: about 30-35 %. Emissions from industries contribute most to the total load of cadmium in the Bothnian Sea river basin district where it stands for about 25 % of the total load.

 Figure 2. Annual load of cadmium to water divided by river basin district and source.
Figure 2. Annual load of cadmium to water divided by river basin district and source.


 

Copper


The total load of copper to water is about 180 000 kg/year and the contribution from forests, agriculture and stormwater are most important. Emissions from point sources (wastewater treatment plants and industries) contribute about 10 % to the total load of copper to water, see figure 3.

 Figure 3. Annual load of copper to water divided by source.
Figure 3. Annual load of copper to water divided by source.


The load of copper to water, divided by river basin district and source, is presented below in figure 4. The contribution from stormwater and agriculture are of greater importance in the southern water districts whereas leaching from forests and other land (mire areas, mountain areas and open land) contribute to a larger extent in the northern districts. Industries only stand for a small part of the copper emissions in all five districts. The largest emissions of copper from industries occur in the Bothnian Sea river basin district where this source corresponds to about 10 % of total load. The contribution from wastewater treatment plants are relatively small in the northern and western districts, but of greater significance for the North Baltic and South Baltic river basin districts.

Figure 4. Annual load of copper to water divided by river basin district and source.
Figure 4. Annual load of copper to water divided by river basin district and source.


 

Nickel


The total load of nickel to water is about 110 000 kg/year. Agriculture, forestry and other land are the most important sources. Emissions from point sources (wastewater treatment plants and industries) stand for about 8 % of the total load of nickel to water, see figure 5.

Figure 5. Annual load of nickel to water divided by source. 
Figure 5. Annual load of nickel to water divided by source.


The load of nickel to water, divided by river basin district and source, is shown in figure 6. Leaching from forests and other land are the most significant sources in the northern districts, whereas agriculture is a more important source in the three southern river basin districts. With the exception of the North Baltic river basin district, emissions of nickel from wastewater treatment plants are only of little significance relative to total emissions per river basin district. Emissions of nickel from industries make up a small part in all five river basin districts, and are most important in the Bothnian Sea river basin district where this source represents about 9 % of the total load.

Figure 6. Annual load of nickel to water divided by river basin district and source.
Figure 6. Annual load of nickel to water divided by river basin district and source.




Lead


The total estimated load of lead to water is about 92 000 kg/year, Forests, atmospheric deposition on lakes and stormwater are the most important sources. Emissions from point sources (wastewater treatment plants and industries) represent about 4 % of the total load of lead to water, see figure 7.

Figure 7. Annual load of lead to water divided by source.
Figure 7. Annual load of lead to water divided by source.


The load of lead to water, divided by river basin district and source, is presented in figure 8 below. Leaching from forests and other land are more important in the north whereas stormwater represents a larger share in the three southern river basin districts. Emissions of lead from industries, wastewater treatment plants and agriculture are relatively small in all five river basin districts. The atmospheric deposition on lakes represents about 20-30 % of the total load of lead in each river basin district.

 Figure 8. Annual load of lead to water divided by river basin district and source.
Figure 8. Annual load of lead to water divided by river basin district and source.


 

Zinc


The total estimated load of zinc to water is about 850 000 kg/year. The contribution from forests, atmospheric deposition on lakes and stormwater are most important. Emissions from point sources (wastewater treatment plants and industries) stands for approximately 13 % of the total load of zinc to water, see figure 9.

Figure 9. Annual load of zinc to water divided by source. 
Figure 9. Annual load of zinc to water divided by source.


The load of zinc to water, divided by river basin district and source, is shown in figure 10. Leaching of zinc from forests contributes close to 40 % of the total load in the Bothnian Bay, the Bothnian Sea and Skagerrak and Kattegat. The contribution from stormwater is most important in the southern river basin districts whereas the contribution from forests, other land and industrial activities are more important in the northern river basin districts.

 Figure 10. Annual load of zinc to water divided by river basin district and source.
Figure 10. Annual load of zinc to water divided by river basin district and source.


 

Mercury


The total load of mercury to water is about 800 kg/year. Forests and other land, stormwater and atmospheric deposition are the most significant sources. Emissions from point sources (wastewater treatment plants and industries) make up about 12 % of the total load of mercury to water, see figure 11.

Figure 11. Annual load of mercury to water divided by source. 
Figure 11. Annual load of mercury to water divided by source.


The load of mercury to water, divided by river basin district and source, is presented in figure 12. The contribution from forests represents about 50 % of the total load of mercury in the Bothnian bay and the Bothnian Sea river basin districts, and about 30 % in the other three districts. Sources such as leaching from agricultural land, local on-site wastewater treatment and industrial activities were of minor significance for all river basin districts.

Figure 12. Annual load of mercury to water divided by river basin district and source. 
Figure 12. Annual load of mercury to water divided by river basin district and source.