USGS examines environmental impacts of aircraft de-icers

January 10, 2007

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 this study.

Study results indicated that anti-icers are more toxic than de-icers due to the larger percent of additives contained in anti-icers. The package of additives used in these fluids varies between manufacturer and type of formulation. In addition, some additives are of special concern not only due to the toxicity of the additive, but because they can become increasingly toxic as they degrade in the environment.

"Airports in cold climates throughout the world use de-icers or anti-icers nearly every day during the winter, and those in warmer climates also must use them periodically. The most intensive de-icing and anti-icing application often occurs during extreme weather conditions including periods of snow, freezing rain, and high winds. This occasionally makes it difficult to contain the spent fluids and they are released to the environment. While they are a necessity for aviation safety, these products are potential environmental contaminants," said Corsi.

The U.S. EPA acknowledges that there is environmental impact from aircraft de-icers and anti-icers and is studying possible guidelines in consideration of national regulation to limit its runoff from airports. Many airports have implemented measures to reduce runoff of chemicals into the environment, so the fate of these substances varies depending on the individual airport and weather conditions during their use.

"Certainly, the primary concern of an airline passenger is a safe arrival at their destination," said Corsi. "Airports have improved spent de-icer collection systems and airlines are considering application methods to reduce the amount of fluids applied. Ultimately, it will take a combined effort from fluid manufacturers, airlines, and airports to continue reducing the environmental impact of aircraft de-icers and anti-icers while maintaining the highest level of safety."

The additives are used in de-icers and anti-icers to facilitate product application, ensure that the product will adhere to aircraft wings and fuselage, and enhance its overall effectiveness.
-end-
Editors: The report, Aquatic Toxicity of Nine Aircraft De-Icer and Anti-Icer Formulations and Relative Toxicity of Additive Package Ingredients Alkylphenol Ethoxylates and 4,5-Methyl-1H-benzotriazoles is available on: http://pubs.acs.org/cgi-bin/abstract.cgi/esthag/2006/40/i23/abs/es0603608.html

USGS provides science for a changing world. For more information, visit www.usgs.gov.

Subscribe to USGS News Releases via our electronic mailing list or RSS feed.

US Geological Survey

Related Aircraft Articles from Brightsurf:

University of South Carolina redefining aircraft production process
The University of South Carolina College of Engineering and Computing will transform the manufacturing and simulation processes used in aircraft production through a $5.7 million NASA grant.

Small altitude changes could cut climate impact of aircraft by up to 59%
Altering the altitudes of less than 2% of flights could reduce contrail-linked climate change by 59%, says a new Imperial study.

Small altitude changes could cut the climate impact of aircraft
Contrails -- the white, fluffy streaks in the sky that form behind planes -- can harm the environment.

New electrodes could increase efficiency of electric vehicles and aircraft
The rise in popularity of electric vehicles and aircraft presents the possibility of moving away from fossil fuels toward a more sustainable future.

Composite metal foam outperforms aluminum for use in aircraft wings
The leading edges of aircraft wings have to meet a very demanding set of characteristics.

Particulate matter from aircraft engines affects airways
In a unique, innovative experiment, researchers under the leadership of the University of Bern have investigated the effect of exhaust particles from aircraft turbine engines on human lung cells.

How to ice-proof the next generation of aircraft
To prevent ice formation on aircraft during flight, current systems utilize the heat generated by burning fuel, but these high-temperature, fuel-dependent systems cannot be used on the proposed all-electric, temperature-sensitive materials of next-generation aircraft.

Putting hybrid-electric aircraft performance to the test
Although hybrid-electric cars are becoming commonplace, similar technology applied to airplanes comes with significantly different challenges.

Aircraft microbiome much like that of homes and offices, study finds
What does flying in a commercial airliner have in common with working at the office or relaxing at home?

Sequential model chips away at mysteries of aircraft
Ice accumulation on aircraft wings is a common contributing factor to airplane accidents.

Read More: Aircraft News and Aircraft Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.