ABSTRACT
Cyanide has been observed as a soil and groundwater contaminant at various current and former industrial sites, including electroplating facilities, aluminum production plants, manufactured gas plants (MGP), steel plants, and metals mining and ore heap leaching facilities. It is one of the most common chemicals found at Superfund sites in the United States [1]. Cyanide has also impacted groundwater as a result of using road salt, which sometimes contains iron-cyanide anticaking agents, for deicing purposes during winter months [2]. At many industrial sites with cyanide-bearing wastes, including aluminum manufacturing and MGP facilities, the leaching of iron-cyanide solids, which are present as onsite fill, can yield detectable concentrations of dissolved cyanide in groundwater. Because of the nature of the cyanide source, dissolved cyanide in groundwater at aluminum facilities and MGP sites consists primarily of soluble iron-cyanide complexes [3-5]. However, in other instances, such as at ore heap leaching sites or electroplating facilities, weak-acid-dissociable (WAD) cyanide complexes and free cyanide are also present, in addition to the iron-cyanide complexes, depending on site conditions.
