Cyanides are salts of a hydrocyanic acid. They are white and in a crystallic form. The most common cyanides are a potassium cyanide and sodium cyanide. 

Cyanides are well soluble in water and alcohol. When mixed with water they can produce a HCN (hydrogen cyanide) odor (almond) or ammonium one (acrid).

When acidificated, a HCN (hydrogen cyanide) is released. HCN is a very toxic gas which belongs in a group of nerve toxins. Some kinds of cyanides are very toxic.

• Cynide limit for drinkable water is max. 0,05 mg/l
• Cyanide limit for drinkable water is max. 0,005 mg/l
• Cyanide limit for natural mineral water is je max. 0,07 mg/l

Use of cyanides

Cyanides are used mainly in chemical and photographic industry. Then in metallurgy and in a produce of rubber or some explosives. Potassium cyanide and sodium cyanide are used a lot as a medium in an electro-chemical metal plating and steel hardening. Cyanides are also used for gold and silver extraction from the minerals.

They are sometimes also used in a non-legal fish catching between the coral reefs.

Occurrence of cyanides in environment

In a small scale they occur naturally as a product of some bacteria, fungi or algae. They can be found in a large amount of plant food.
A big source of cyanides are usually industrial waste waters, mostly from surface and heat treatment of metals and mining industry. Then waste waters from photographic industry. Cyanides are very toxic to fish etc..

Cyanides and health

Cyanides are very dangerous and toxic. Deadly dose of a potassium cyanide to human is 200 mg. Cyanide blocks the tissues from oxygen processing.

Symptoms: tiredness, headaches, noise in ears and nausea.