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Cyanides - total as CN

total CN

SPRI Emission Reporting Threshold
50.0 Kg/yr Pollutant Emissions to Land
50.0 Kg/yr Pollutant Emissions to Water
50.0 Kg/yr Pollutant Emissions to Waste Water
This sheet is a generic summary, designed to give the reader a basic level of background information about the substance in question. Great care has been taken to represent as effectively and correctly as possible the broad range of (not necessarily consistent) information which is available from a variety of sources. The reader must accept therefore that this sheet has no legal status and cannot be relied upon in any legal proceedings. SEPA disclaims any responsibility or liability whatsoever for errors and omissions in this sheet.
What is it?
Cyanide is a unit of the two elements carbon and nitrogen. It is usually found in combination with hydrogen, sodium and potassium. Hydrogen cyanide is a colourless gas with a faint almond smell, which mixes with water and alcohol. Sodium and potassium cyanides are white solids with the same faint almond smell.
What is it used for?
Compounds of cyanide are used in metal processing, chemical production, photographic development, manufacture of plastics, rubber and explosives, as pesticides, to separate gold and silver from their natural geological ores, in electroplating and in the hardening of steel.
Where does it come from?
Most of the cyanide found in the environment originates from vehicle exhaust, industrial and chemical processes, waste incineration and from their use as pesticides. Trace amounts are found in cigarette smoke. Small quantities are released naturally from bacteria, fungi and algae and it is also present in some foods and plants.
How might it affect the environment?
Cyanides in water are very toxic to aquatic life. They are also toxic when inhaled from the air by terrestrial animals. Cyanides are not persistent in water or soils and are unlikely to accumulate in aquatic life. They are not thought to have any environmental effects at a global level.
How might exposure to it affect human health?
Exposure to potentially damaging levels of cyanides would only usually occur in occupational settings or where there was an accidental release. Cigarette smokers may also be exposed to significant amounts. Long-term exposure to moderate levels may result in breathing difficulties, heart pain, vomiting, blood changes, headaches, convulsions and thyroid problems. Exposure to extremely high levels might result in damage to the brain or heart and cause coma or even death.
What steps are being taken to limit the potential impacts?
In the UK (including Scotland) releases of cyanides are controlled through the Pollution Prevention and Control (PPC) regulations. European Directives controlling emissions of cyanides include those concerned with pollution of aquatic environments (76/464/EEC); and on the treatment of hazardous wastes (91/689/EEC).