The U.S. Geological Survey (USGS) has been examining the relative toxicity to aquatic life from a variety of formulations used to remove or prevent dangerous ice buildup on aircraft. A recent study has confirmed that proprietary additives are responsible for the observed toxicity. This USGS study, published in the journal Environmental Science & Technology, compared nine different formulations. Neither the primary ingredients (ethylene glycol and propylene glycol) nor the known additives accounted for all observed toxicity of these formulations.
Additives are included to improve a formulation's effectiveness. Those that are proprietary have compositions known only to the manufacturer. Although research conducted in the mid 1990's revealed the toxicity of proprietary additives, this study compared numerous de-icers and anti-icers and confirmed that most still have toxic additives that have not been publicly identified.
"This study suggests that some de-icers -- products that remove snow and ice buildup that are currently in use are safer for the environment than the de-icers used in the 1990's," said Steve Corsi, USGS scientist and lead author of this study. "But the toxicity profiles of anti-icers -- products that prevent ice and snow buildup -- have not changed significantly."
For this study, completed in cooperation with Milwaukee's General Mitchell International Airport and the Dallas-Fort Worth Airport, formulations were collected directly from storage tanks and de-icing vehicles and tested on minnows, water fleas, green alga, and marine bacterium. These organisms are near the bottom of the food chain and are common benchmark indicators of environmental health. The sensitivity of tested organisms varied according to a number of factors including formulation of the product. Concentrations of deicer and anti-icer components previously observed in airport effluents have, at times, exceeded the toxicity levels shown in results of
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Contact: Steven Corsi
srcorsi@usgs.gov
608-821-3835
United States Geological Survey
10-Jan-2007