Levels of mercury, lead and cadmium in Swedish forest soils have increased markedly in recent centuries due to large-scale atmospheric emissions in Sweden and elsewhere.
In large areas of Sweden levels of lead and mercury are high enough to affect microbiological activity in forest soils. Nutrient conversion in the soil might be disturbed, which can have unpredictable ramifications throughout the forest ecosystems.
Diet recommendations are issued
As a result of high mercury levels in the soil, pike and other freshwater fish now contain so much mercury as to be unfit for human consumption. Freshwater fish in many parts of the country contain mercury at approximately five times the estimated background level. The National Food Administration has therefore issued cost recommendations for certain types of fish.
Deposition of lead and cadmium has decreased significantly in recent decades. Mercury deposition has also decreased, but it is still far too high. Mercury, lead and cadmium are being withdrawn from use in Sweden, but other countries also need to reduce their use of these metals.
Other metals have less impact on the environment. The biggest problem is emissions from motor vehicles, which are still the source of far too much copper, zinc, chromium and nickel, among others.
The rapid increase of cadmium concentrations in herring liver at Landsort
in the Baltic Proper seems to have stopped. Concentrations are now
decreasing. Source: Swedish Museum of Natural History, National Environmental
Monitoring, Official Statistics.
International cooperation
The Swedish Environmental Protection Agency is working through the UN and the EU to achieve reductions in the use and emissions of heavy metals.