Environment

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DDT Persists in Penguins Despite Decades-Old Ban

May 07, 2008 08:00 AM
by findingDulcinea Staff
by Lindsey Chapman
The levels of DDT in Antarctic Adélie penguins have remained constant despite the fact the pesticide was banned in the Northern Hemisphere in the 1970s.

30-Second Summary

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DDT was developed in the 1940s to kill mosquitoes and prevent insect-borne diseases such as malaria. It’s also been used for insect control on crops.

In 1973, the United States banned DDT because of the variety of risks it posed to human and environmental health. Other countries have similar bans, although a few still use the pesticide to help control disease.

The DDT bans have helped the environment. In the Arctic, DDT levels have steadily declined. However, in the Antarctic the levels of the chemical appear to be much the same as when it was banned. The area’s Adélie penguins also have the chemical in their systems.

Researchers measured DDT levels in 12 dead penguins and 27 ruined penguin eggs. The chemical measured at levels similar to those detected in the 1960s and 1970s. However, because the sampling of penguins wasn’t very sizeable, the results are inconclusive.

Although DDT was never used in Antarctica, it traveled there through the atmosphere and was deposited in ice, snow and ocean water. Scientists blame the continued presence of DDT on the melting of glacial ice.

After the chemical enters the water, it is consumed by various organisms, moving up the food chain until it is ingested by penguins.

The quantities of DDT in the penguins aren’t large enough to harm the birds, but its continued presence shows just how long the chemical stays in the environment, says Heidi Geisz, a researcher who helped with the penguin study.

Headline Links: DDT in the Antarctic

Historical Context: Understanding DDT’s effects

Related Topics: Health risks of DDT

Reference: What is DDT?

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