Household chemicals eyed as cause of duck deaths
July 28, 2010
DENVER (AP) – Chemicals found in household cleaners, detergents and fabric softeners are suspected of playing a role in the deaths of hundreds of ducks in Denver in 2007 and 2008, according to a study by the U.S. Geological Survey.
The study released Tuesday found the ducks were exposed to a class of chemicals known as surfactants that may have compromised the birds’ ability to shed water off their feathers.
Many of the ducks died during the winter from hypothermia or drowning because of a change in the physical makeup of their feathers.
The U.S. Fish and Wildlife Service asked for the study after an abnormally large number of birds were discovered dead near several wastewater treatment plants. It was the only mass duck die-off its kind nationally. Avian flu and other causes were immediately ruled out.
No one expected what investigators found, said John Wegrzyn, a Fish and Wildlife biologist who worked on the study. “When we got the results back, we were like, ‘Really?”‘
Surfactants reduce the surface tension in water and give cleaners the properties that allow them to remove dirt.
A specific type of surfactant discovered on the dead birds’ feathers was polyethylene glycol, a chemical removed from wastewater at the plants. Researchers are puzzled because not all ducks found with the chemical in their feathers lose their “waterproofing.”
Researchers plan to examine what combination of chemicals in wastewater-treatment systems affects the ducks.
“We spent a lot of time, money and effort getting to this point, and we still don’t have a lot of answers,” Wegrzyn said.
Most of the dead ducks were northern shovelers, which unlike other ducks that feed on vegetation and insects, feed mostly on microorganisms such as algae. They also spend more time in water.