Application of organic dye measurements in airport stormwater as tracers for assessing runoff of aircraft deicing/anti-icing fluids

Aircraft deicing and anti-icing fluids are used extensively during winter weather events at airports to minimize risks of ice/snow-related safety incidents.  The widespread use of these fluids, which contain a number of potentially hazardous organic contaminants (including glycols, benzotriazole corrosion inhibitors, surfactants, and thickeners) has led to significant concern over their impacts on surface waters and groundwaters in proximity to airports.  In many cases, deicing and anti-icing fluids enter aquatic systems directly through runoff of stormwater from airports during precipitation events or after melting of snowbanks containing residues of these fluids.

Heretofore, it has been difficult to trace the contribution of deicers vs. anti-icing fluids (which are more toxic) to stormwater loads of BOD and other markers of organic contaminant concentrations.  We are taking advantage of the unique and relatively class-specific organic dyes that are used in deicer/anti-icer fluids in order to trace inputs of these two major types of deicing fluids to surface waters.  Dyes (primarily food-grade azo-dyes) are added to deicing and anti-icing fluid formulations in order to aid the operator in both application and selection of the fluids during a deicing event.

Our results to date indicate that dye identity and concentration are unique between anti-icing and deicing fluids.  Measurement of these dyes in surface waters and runoff samples indicates that they can be used as a reliable tracer for deicing and anti-icing fluid inputs to stormwater.  In collaboration with our collaborator Steven Corsi at the U.S. Geological Survey in Wisconsin, we are applying this method to complete a detailed study of the impact of deicing/anti-icing fluids on stormwater adjacent to a major commercial airport in the upper Midwestern U.S.