Levels of total cyanide and NaCl in surface waters adjacent to road salt storage facilities.

Concentrations of Na, Cl and total cyanide (simple+complex forms of cyanide) in surface waters adjacent to uncovered, outdoor sand-salt storage facilities were monitored for the calendar year 1988. Runoff of deicing salt from these unprotected sand-salt piles resulted in Cl concentrations up to 13,500 mg liter(-1) in surrounding surface waters indicating substantial leaching of road salt from sand-salt storage lots. The use of sodium hexacyanoferrate (II) as an anti-caking agent in road salt resulted in up to 200 microg liter(-1) total cyanide (CN) in surface waters adjacent to sand-salt piles. Concentrations of Na and Cl were highest during the summer months whereas the concentrations of total CN were highest during the autumn months. The observed concentrations of total CN were less than the calculated maximum concentrations based on total CN content of pure road salt indicating that sodium hexacyanoferrate(II) was being adsorbed during overland flow onto soils and/or sediments of the wetlands. A laboratory adsorption study using five soils and a road salt solution showed that the soils adsorbed from 25 to 83% of the sodium hexacyanoferrate(II) present in the soil-road salt suspensions. The percentage of sodium hexacyanoferrate(II) adsorbed on soils increased with decreasing soil pH.