Pesticide DDT shows up in Antarctic penguins

By Deborah Zabarenko, Environment Correspondent

WASHINGTON (Reuters) - The pesticide DDT, banned decades ago in much of the world, still shows up in penguins in Antarctica, probably due to the chemical's accumulation in melting glaciers, a sea bird expert said on Friday.

Adelie penguins, known for their waddling gait and a habit of nesting on stones, have long shown evidence of DDT in their fatty tissues, although not in enough concentration to hurt the birds, according to Heidi Geisz of the Virginia Institute of Marine Science.

But researchers were surprised to see that the level of the pesticide in Adelies' fat had not declined, even after DDT was banned for exterior use in the 1970s in the United States and elsewhere.

First noted in 1964, while the chemical was still widely used, the amount of DDT found in Adelie penguins rose in the 1970s and has stayed stable since then, Geisz said in a telephone interview.

In findings published in the journal Environmental Science & Technology, Geisz and her colleagues noted that persistent organic pollutants like DDT accumulate and become concentrated in the Antarctic ecosystem.

"DDT, along with a lot of other of these organic contaminants, actually travel through the atmosphere ... toward the polar regions by a process of evaporation and then condensation in cooler climates," Geisz said, explaining this is how the pesticide got deposited in Antarctic glaciers.

DDT declined dramatically in Arctic wildlife over the last decade, while the amount of the chemical in Antarctic Adelies stayed stable, the study said.

DDT was easily detectable in glacier melt water, Geisz said.