U.S. Department of the Interior
U.S. Geological Survey
News Release
January 10, 2007 Steven Corsi 608-821-3835 srcorsi@xxxxxxxx
USGS Examines Environmental Impacts of
Aircraft De-Icers
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
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.
USGS provides science for a changing
world. For more information, visit www.usgs.gov.
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Diane Noserale
Media Relations, Eastern Region
U.S. Geological Survey
150 National Center
Reston, VA 20192
phone: 703-648-4333
fax: 703-648-4588
