Potential water-quality effects from iron cyanide anticaking agents in road salt

Water-soluble iron cyanide compounds are widely used as anticaking agents i n road salt, which creates potential contamination of surface and groundwat er with these compounds when the salt dissolves and is washed off roads in runoff. This paper presents a summary of available information on iron cyan ide use in road salt and its potential effects on water quality. Also, esti mates of total cyanide concentrations in snow-melt runoff from roadways are presented as simple mass-balance calculations. Although available informat ion does not indicate a widespread problem, it also is clear that the water -quality effects of cyanide in road salt have not been examined much. Consi dering the large, and increasing, volume of road salt used for deicing, stu dies are needed to determine levels of total and free cyanide in surface an d groundwater adjacent to salt storage facilities and along roads with open drainage ditches. Results could be combined with current knowledge of the fate and transport of cyanide to assess water-quality effects of iron cyani de anticaking agents used in road salt.