[ RadSafe ] Nuclear Power/ Greenhouse Effect/ Massive AfricanHumanImpacts
jaro-10kbq at sympatico.ca
Fri Oct 28 09:01:53 CDT 2005
Jim wrote: " the assertions of millions of deaths due to the banning of DDT
I first came across the DDT debate in my college Biology textbook by Helena
Curtis (which I still have). She tells very briefly of the magnificent
success of eradicating malaria deaths in certain tropical countries -- and
how the disease returned almost to pre-DDT years following its baning -- in
those countries that unfortunately chose to follow the US's lead - or were
unable to secure an equally low-cost supply following the shutdown of US DDT
>From the article pasted below :
" In Ceylon (now Sri Lanka), where about 2.5 million cases of malaria were
recorded annually in the 1950s, regular spraying led to just 31 reported
cases in 1962.
Today, there are roughly 300 to 500 million cases of malaria a year and 2.7
million deaths. The judicious use of DDT has the potential to make a huge
THE RIGHT CHEMISTRY
The ban on DDT has hidden cost
While it may be a double-edged sword, the feared pesticide can save lives
Joe Schwarcz [The Montreal Gazette, 14 July 2003]
Joe Schwarcz is director of McGill University’s Office for Science and
Society (www.mcgill.ca/chempublic). He can be heard every Sunday from 4-5
p.m. on CJAD. joe.schwarcz at mcgill.ca
When the Germans retreated from the Italian city of Naples during the Second
World War, they dynamited the city’s water system. The inhabitants had no
water to wash with, and body lice proliferated. The result was an outbreak
of “typhus bellicus,” or “war typhus,” a disease that in previous wars had
killed millions. This time though, the Allies had an answer. They had DDT.
About 1.3 million Neapolitans were dusted with a mixture of talcum powder
and DDT, and within three weeks the epidemic was stopped in its tracks. But
that was only the beginning.
DDT turned out to be highly effective against mosquitoes that transmitted
malaria Sprayed on the walls of houses in the tropics, it would keep
mosquitoes away for weeks.
In Ceylon (now Sri Lanka), where about 2.5 million cases of malaria were
recorded annually in the 1950s, regular spraying led to just 31 reported
cases in 1962. That year also marked the publication of Rachel Carson’s
Silent Spring, in which she described DDT as the “elixir of death.” She wasn
’t referring to insects.
Carson, who trained as a biologist, was convinced that DDT and other similar
pesticides had unleashed a catastrophic plague on the world. She predicted
that wildlife would be affected to an extent where no birds would be left to
sing in the spring, that the persistent DDT would accumulate in the bodies
of mammals causing cancer rates to soar.
She was right about the persistence and accumulation of DDT. Both it and its
major metabolite, DDE, persist in the environment that can have “gender
bending” for many years. They are essentially insoluble in water but are
very soluble in fat. This means that they accumulate in fatty tissue and
build up in the food chain. While plankton in water may have very little
DDT, the fish that eat the plankton will have more, and birds that eat the
fish more yet. We all have some DDT in our flesh that can be traced back to
the massive spraying of fields and vast amounts used in insect control
before 1972, when most uses of DDT were banned in North America. Indeed, in
1962, 80 million kilograms of DDT were used.
Carson was correct when she said that DDT can be found in polar bears and at
sites far removed from where it was applied. But its presence is not enough
to condemn it.
What other evidence did Rachel Carson have? Silent Spring is dedicated to
Albert Schweitzer and his quote that “man has lost the capacity to foresee
and to forestall and will end by destroying the Earth.” Carson’s implication
was that the famous physician was speaking about DDT. Actually, as he makes
clear in his autobiography, Schweitzer was a proponent of DDT to control
malaria, and the quote refers not to DDT, but to nuclear warfare.
This is not the only instance in which Carson played loose with the facts.
She references a paper by James DeWitt in the Journal of Agricultural and
Food Chemistry to support her thesis that a decline in certain bird
populations was due to the thinning of egg shells caused by DDT. Actually,
the reference does not offer much support. DeWitt fed quail DDT at doses
roughly 3,000 times greater than any human was ever exposed to and found
that 80 per cent of their eggs hatched. The hatch rate in the control group,
not fed DDT, was 84 per cent. Hardly a spectacular difference, especially
when the huge dose is considered. Carson is also silent about the fact that
in the same study, eggs from pheasants fed DDT had a higher hatch rate than
What about the possibility that DDT is harmful to humans? It certainly
presents no acute toxicity. I wouldn’t recommend it as a dietary staple, but
J. Gordon Edwards of San Jose State University, an expert on the toxicity of
insecticides and a vocal critic of DDT’s opponents, would often begin a
lecture on DDT by eating a spoonful. Now retired, he still climbs mountains
at the age of 83. Human volunteers have eaten 35 milligrams of DDT for two
years with no consequences. Of course, of greater concern is the possibility
of chronic effects. Can DDT cause cancer in the long run? Apparently not.
Over 80 peer-reviewed scientific publications attest to this fact, many
having followed workers who had extensive DDT exposure.
National Cancer Institute researchers found no link between tissue samples
of DDT and the disease. This was comforting, because DDT does have possible
hormone disrupting effects, and a connection to breast cancer had been
hypothesized. Certainly, the presence of compounds that can have “gender
bending” effects in the environment is undesirable. But not as undesirable
as people dying. And they are dying of malaria in droves.
Why Ceylon stopped spraying DDT in 1964 is contentious, but what is clear is
that by 1969, the country was again recording 2.5 million cases of malaria a
year. In 1996, because of environmental pressure, South Africa stopped
spraying with DDT. A malaria epidemic ensued and was only curtailed when DDT
application was resumed four years later. Today, there are roughly 300 to
500 million cases of malaria a year and 2.7 million deaths. The judicious
use of DDT has the potential to make a huge impact. Yes, there are concerns
about insects developing resistance. Indeed, that was one of the reasons
cited for banning DDT. Actually, the resistance was fostered by farmers who
way overused DDT on cotton crops, not by using DDT to control mosquitoes.
There is also clear evidence that DDT even deters mosquitoes that are
resistant to its insecticidal properties.
DDT may be a double-edged sword, but its unqualified ban seems shortsighted.
The world may not need DDT for agriculture any more, but it needs it to
battle malaria. As I sit here, thinking about an appropriate conclusion, I’m
listening to birds happily chirping outside my window. But I also know that
during the time it took me to write this column, more than 200 children have
been permanently silenced by malaria. Silenced by conclusions about DDT that
went beyond the science.
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