Copper sulphate: what use, what danger?

Available in drugstores, copper sulfate is generally in solid form. It is used for its fungicidal and bactericidal properties. He thus enters the composition of the Bordeaux mixture.

copper sulphateCopper sulfate in Bordeaux mixture

The dose of copper sulphate required for the preparation of the Bordeaux mixture  (a pesticide that fights mushrooms) depends on the plants to be treated. The generally accepted dose is 200 g per 10 liters of Bordeaux mixture. Note that the copper sulfate must first be diluted in 2 liters of water. The slaked lime is prepared separately, using 400 g of lime for 4 liters of water. Once these two solutions are made, they can then be mixed by adding 4 liters of water. The Bordeaux mixture must rest a day before its application.

Copper sulfate in for the maintenance of a swimming pool

Copper sulfate is used to prevent or treat the formation of algae in a pool. The treatment is done only at the beginning of the season or just before the winter, in order to avoid any risk for the swimmers (because of attention, danger …). The dosage of copper sulfate is one-half gram per cubic meter. In the case of particularly dirty swimming pool water, the dose can, however, be increased to 1 gram per cubic meter.

The dangers of copper sulfate

Copper sulfate is toxic. Inhalation, ingestion or simple skin contact, it causes violent reactions. It is therefore recommended to use it carefully and to equip gloves, protective clothing, and a mask to handle it. In addition, copper sulfate dissolves in water: its use around a lake or watercourse is therefore prohibited, in order to avoid any risk of pollution.

One of the main current uses of copper sulfate is the preparation (industrial or not) of fungicides for agriculture including organic. The most common form is the Bordeaux mixture of copper sulfate neutralized with lime. This one makes it possible to neutralize the acidity created by the setting in a solution of the sulfate of copper. Plants treated with a copper sulfate preparation have pale blue streaks consisting of mixed salts of hydroxide and copper sulfate.

Copper sulfate was formerly called “blue vitriol”. It has long been used as a chemical weed killer (especially potatoes). Some owners of family swimming pools use it as an algaecide, which is to be avoided if one exceeds the dosage of 2g / M3¬† [ref. necessary] . Indeed, copper sulfate does not degrade in water and because of this causes allergies, it verifies hair discolored with hydrogen peroxide, causes colic … In addition, it penetrates the heart of the plastic of seals of the basins (liner and reinforced membrane) and stains indelibly. [ref. necessary]