Granato, G.E., 1996, Deicing chemicals as a source of constituents in highway runoff. Transportation Research Record 1533, Transportation Research Board, National Research Council, Washington D.C., p. 50-58.

The dissolved major and trace constituents of deicing chemicals as a source of constituents in highway runoff must be quantified for interpretive studies of highway runoff and its effects on surface and groundwater. Dissolved constituents of the deicing chemicals--sodium chloride, calcium chloride, and premix (a mixture of sodium and calcium chloride)--were determined by analysis of salt solutions created in the laboratory, and are presented as mass ratios to chloride. Deicing chemical samples studied are about 98 and 97 percent pure sodium chloride and calcium chloride, respectively; however, each has a distinct major and trace ion constituent signature. The greatest impurity in sodium chloride road-salt samples was sulfate followed by calcium, potassium, bromide, vanadium, magnesium, and fluoride, and other constituents with a ratio to chloride of less than 0.0001 by mass. The greatest impurity in the calcium chloride road-salt samples was sodium followed by potassium, sulfate, bromide, silica, fluoride, strontium, and magnesium, and other constituents with a ratio to chloride of less than 0.0001 by mass. Major constituents of deicing chemicals in highway runoff may account for a substantial source of annual chemical loads. Comparison of estimated annual loads and first flush concentrations of deicing chemical constituents in highway runoff with those reported in the literature indicate that although deicing chemicals are not a primary source of trace constituents, they are not a trivial source either. Therefore, deicing chemicals should be considered as a source of many major and trace constituents in highway and urban runoff.

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