Global use of the pesticide DDT has been sharply curtailed since the 1970s, so it’s natural to expect that over time, less of it would find its way into living creatures. And that has generally been the case: although many organisms still have detectable levels of DDT in fatty tissues, those levels have generally declined.

Not so among Adélie penguins in the Western Antarctic Peninsula, however, according to a study in the journal Environmental Science and Technology. DDT levels in these birds have remained about the same in the past 30 years, and the researchers say it’s likely that Antarctic glaciers, which would have accumulated DDT through atmospheric deposition before its use was restricted, are delivering the pesticide into the food chain through meltwater.

Image DDT levels in Adélie penguins in Antarctica have stayed the same. Credit... Heidi N. Geisz

The lead author, Heidi N. Geisz of the Virginia Institute of Marine Science of the College of William and Mary, said that the purpose of the study “was not to further vilify DDT.” The findings, she said, may help in studying the persistence of organic pollutants like PCBs.