Water

The main water contaminants caused by agriculture are nitrate and phosphate fertilisers and pesticides.

Nitrates in water are recognised to create risks of stomach cancer and "blue baby syndrome". According to the Commission, 8% of water supplies in Denmark and 5-6% in western Germany exceed the EU level while it is expected that 20% in France and 25% in the Netherlands may exceed the level in the next few years.

Phosphate fertilisers cause a strange form of pollution called "eutrophication". It means "too well nourished". Too much phosphate in still water depletes oxygen and poisons fish and others. Algae are a visible sign of the process - the water blooms and the plants below die, taking the oxygen.

More from DEFRA on Nitrate and Phosphate water pollution

About half the additional nitrogen and a quarter of the phosphorus entering the North Sea comes from agriculture. Concentrations of agricultural nutrients reach the highest levels in estuaries where they may be 1000X more than fertilised fields.

Blooms of toxic algae in lakes and reservoirs off the Adriatic and Scandinavia kill fish and disrupt the tourist industry. Deoxygenation of deeper waters due to the decay of increased organic matter is another consequence. As a result, in the Baltic, spawning sites for fish become scarce.

More and more pesticides are found in the marine environment. Twelve pesticides have been found in the North Sea, but their effects impossible to predict, because of the complexities of the marine communities. It has been estimated that the weight of pesticide carried by the Rhine at the Dutch border is more than 80 tonnes per year.