Germany's coal-fired power plants are emitting seven tonnes of hazardous mercury per year, making the country the worst European quicksilver polluter after Poland and Greece, a study has shown.
Conducted by the Hamburg Institute of Ecology and Politics on behalf of the opposition Green Party, the research found that Germany - which has been at the forefront of promoting clean energy - is emitting about two tonnes more than previously thought.
Quicksilver, which is emitted into the atmosphere and also finds its way into the food chain, can cause neurological damage and cancers. Particularly among children, it has been found to result in symptoms like IQ loss and delayed speech.
Germany is still heavily reliant on coal-fired power generation, which covers 40 per cent of its energy needs.
Oliver Krischer, deputy head of the Greens in parliament, called on the German government to follow the example set by the United States, which recently announced the strictest mercury emissions limits worldwide.
Germany is also trying to lower the limit, and has committed to allowing a maximum of one microgramme of mercury per cubic metre a day from 2019.
German Environment Minister Barbara Hendricks responded to the criticism levelled by the opposition by defending the government's existing policy and saying that further measures were not necessary.
There is increasing pressure on the world's biggest consumers of energy after world leaders met in Paris in December to hammer out a climate deal and to encourage companies to invest in clean energy to reduce air pollution.