February 19, 2009

Runway deicers may harm aquatic life

The U.S. Geological Survey says it has determined chemicals used to remove ice from airport runways may do more environmental harm than previously realized.

The USGS says 67 percent of U.S. airports that apply deicers to runways use a potassium acetate compound that might be harmful to aquatic life. Airports during the 1990s airports began using that compound to replace urea, which was known to contribute toxic ammonia to nearby streams.

In the first published study of potassium acetate in airport runoff, USGS scientists said they collected water samples from streams near Milwaukee's General Mitchell International Airport shortly before the airport began using potassium acetate to replace urea.

The USGS scientists said they found 40 percent of the samples collected following the change had concentrations of potassium acetate at levels high enough to be detrimental to aquatic life.

Scientists also tested for other deicing products including pavement deicer (sodium formate), aircraft deicer (propylene glycol) and road salt (sodium chloride).

They said they found a complex mixture of chemicals in airport runoff with many potential effects. Road salt was present at very high concentrations and most likely has detrimental effects on aquatic life, the USGS said. Aircraft deicers were present at concentrations that can harm aquatic life, but sodium formate pavement deicer concentrations were relatively low.

The full report is available online at: http://pubs.acs.org/doi/abs/10.1021/es8017732.