Cyanides are mainly present as hydrogen cyanide and alkali cyanides such as sodium and potassium cyanide. Hydrogen cyanide is a colourless gas with an almond like odour. Sodium cyanide and potassium cyanide are both white solids and may smell of hydrogen cyanide as well as of ammonia, especially when in contact with water.
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Common name: Cyanides
Use
Alkali cyanides are used in the extraction of gold and silver, as depressants in the extraction of base metals, in chemical synthesis and for surface treatment of metals.
Releases to the environment
Cyanide is found naturally in the environment in very small quantities, where it can be produced by certain bacteria, fungi, and algae, and it is also found in a number of foods and plants. Cyanides are released to waters from various industrial processes. Metal finishing and organic chemical industry as well as iron and steel production are major sources of cyanide release.
Impacts on the environment and human health
Cyanides are very toxic by ingestion, skin contact and by inhalation. The brain and the cardiovascular system are the main organs affected by cyanide poisoning. Cyanides are generally not persistent when released to water and soil, and are not likely to accumulate in aquatic life. They are however very toxic to fish and other forms of aquatic life.
International actions
Cyanides are listed as priority hazardous substance in of the EU Water Framework Directive and in the Basel Convention controlling the transboundary movements of hazardous wastes. Furthermore cyanides are on the EU-Commissions EPER list and listed in the PRTR Protocol under the Århus Convention.
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