Fact Sheet: Cyanide


Brief Overview:
Contaminant: Cyanide
Category: Inorganic
Treatment: Ion Exchange, Reverse Osmosis, Chlorine

Cyanide is a carbon-nitrogen chemical unit which combines with many organic and inorganic compounds. The most commonly used form, hydrogen cyanide, is mainly used to make the compounds needed to make nylon and other synthetic fibers and resins. Other cyanides are used as herbicides.

Production of the most common cyanides was roughly 5 billion pounds a year in the late 1980s and early 1990s. The major cyanide releases to water are discharges from metal finishing industries, iron and steel mills, and organic chemical industries. Releases to soil appear to be primarily from disposal of cyanide wastes in landfills and the use of cyanide-containing road salts. Chlorination treatment of some wastewaters can produce cyanides as a by-product.

From 1987 to 1993, according to the Toxics Release Inventory cyanide compound releases to land and water totaled about 1.5 million lbs. These releases were primarily from steel mills and metal heat treating industries. The largest releases occurred in California and Pennsylvania.

What happens to Cyanide when it is released to the environment? Cyanides are generally not persistent when released to water or soil, and are not likely to accumulate in aquatic life. They rapidly evaporate and are broken down by microbes. They do not bind to soils and may leach to ground water.

Short-term: EPA has found cyanide to potentially cause the following health effects when people are exposed to it at levels above the MCL for relatively short periods of time: rapid breathing, tremors and other neurological effects.
Long-term: Cyanide has the potential to cause the following effects from a lifetime exposure at levels above the MCL: weight loss, thyroid effects, nerve damage.


Ion Exchange, Reverse Osmosis, Chlorine