The ‘Bordeaux mixture’ is a mixture of copper (II) sulphate and slaked lime (calcium hydroxide) in water that is used as a fungicide in the vineyard. The use of Bordeaux mixture is nowadays often prohibited because its use can lead to a build-up of copper in the soil. Copper is a heavy metal, hardly rinses out and is not degradable. In elevated concentrations, copper can be toxic to microorganisms and other soil life. In France it can still be used, although the use is bound by statutory maximum quantities. Bordeaux mixture is also called ‘Bouillie Bordelaise’.