PHA-Exchange> Looming DDT Ban Spurs Debate On Malaria

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from Vern Weitzel <vern.weitzel at undp.org> 

http://www.enn.com/news/2004-05-18/s_23972.asp

Set for ban, DDT lingers in battle against malaria
By Alister Doyle, Reuters

OSLO, Norway - Few poisons have ridden such a roller coaster through
environmental history as DDT.

Once hailed as a miracle pesticide, DDT is outlawed as one of a "Dirty
Dozen" chemicals as of Monday, even as it stays in use as a controversial
spray against malaria-spreading mosquitoes.

The man who discovered its power to kill insects won a Nobel Prize in
1948, while shock at its damage to wildlife awoke a global environmental
movement in the 1960s.

Into the 21st century, countries including South Africa and Ethiopia still
swear by DDT to combat malaria, which kills a million people a year. They
say there is scant evidence that DDT is carcinogenic for humans.

"There is still a role for DDT," said Jim Willis, head of the U.N.
Environment Program (UNEP) chemicals division, estimating that about 25
countries will use DDT under exemptions from the DDT pesticide ban.

DDT is one of 12 industrial chemicals to be outlawed under the U.N.'s 2001
Stockholm Convention on persistent organic pollutants (POPs), which
formally comes into force on Monday after ratification by 50 states.

Developing countries have a difficult choice in using a known poison to
spray homes, yet malaria kills one African child every 30 seconds,
according to U.N. estimates. The disease burdens health budgets and curbs
economic growth.

Best known by its initials, dichloro-diphenyl-trichloromethylmethane can
suppress the immune system and is infamous for threatening bird
populations by thinning eggshells.

No Health Damage?

"We have seen no conclusive evidence that it (spraying) has any impact on
human health. We put very small quantities of DDT on the wall (of people's
houses)," said Devanand Moonasar, national malaria program manager of
South Africa's National Department of Health. "We spray only under the
eaves and also inside the houses of traditional mud structures," he said,
adding that spraying was normally done from August to October when
mosquitoes were worst.

Still, workers use full protective clothing for spraying, and U.N.
warnings about DDT and the rest of the "Dirty Dozen" POPs are stark.

"Of all the pollutants released into the environment every year by human
activity, POPS are the most dangerous," said UNEP chief Klaus Toepfer,
adding that the world should hunt for alternatives to DDT to control
malaria.

DDT and other POPs including dioxins or pesticides like aldrin or
chlordane are found worldwide but build into highest concentrations in the
fatty tissues of people in the Arctic and in animals from polar bears to
seals. In the heavily industrialized Northern Hemisphere, the chemicals
are swept north by ocean currents and winds and end up lodging in fatty
tissues in the apparently pristine Arctic.

"There is a conflict between the interests of the people in the Arctic and
those who are living in areas where DDT is used," said Lars-Otto Reiersen,
head of the Arctic Monitoring and Assessment Program.

He said that a main modern source of DDT in the Arctic was Russia.
Measurements showed that it was still in use there, perhaps as a crop
spray. Russia has signed but not yet ratified the POPs convention.

Most western countries banned DDT in the 1970s.

The WWF environmental group said that more efforts should be put into
finding less toxic alternatives to DDT in fighting malaria.

"It's still a very dangerous chemical," said Samantha Smith, director of
the WWF's Arctic program.

Napoleon's Lice

Towards the end of World War II, DDT was found to be potent in killing
lice that spread typhus among soldiers. Lice-borne diseases had ravaged
armies throughout history, including Napoleon's forces in his ill-fated
1812 march to Moscow.

"Unexpectedly, dramatically, practically out of the blue, DDT appeared as
a deus ex machina," said Sweden's G. Fischer in a speech awarding the 1948
Nobel Medicine Prize to Switzerland's Paul Hermann Muller for his DDT
discovery.

But in 1962, U.S. author Rachel Carson made DDT infamous in her landmark
book Silent Spring, detailing the risks of using industrial chemicals. The
book is credited with spurring global environmental awareness.

UNEP's Willis said there was hope for a world rid of DDT but that it could
take decades.

"Mexico recently stopped using DDT, and they've seen at the same time a
reduction in malaria rates," he said.

He said that broader antimalaria policies included clearing stagnant water
where mosquitoes breed, placing nets around beds at night, targeted use of
alternative antimosquito pesticides, and development of new medicines.




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