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Based on the comments, the article "Soaring to new heights" in today's Journal World has provided yet another opportunity for some people to peddle misinformation about DDT. Perhaps rather than cite Fox News or the "Junk Science Web Site", these people ought to look more closely at the scientific literature on DDT and its effect on bird populations. Here for instance, is a review that classes DDE, a metabolite of DDT, as an endocrine disruptor. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1874172Meanwhile, a major 1995 study concluded that environmental pollutants appear to be the most important factor relating to productivity of eagle populations:http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1519271.For birds of prey the connection between DDT/DDE and reproductive failure seems pretty strong to me.Of course biology is rarely neat, and there are certainly studies that do not show a link between DDT and it's metabolites and changes in bird populations. For instance, a very recent filed study that shows that a population of herons is thriving in spite of exposure to PCB's and DDE's.http://www.news.uiuc.edu/NEWS/08/0116herons.htmlAnd consider this study which concluded that DDT, more precisely DDE, probably was not involved in the decline of California condors.http://www.blackwell-synergy.com/doi/abs/10.1046/j.1474-919X.2003.00132.xIndeed this study concludes that lead shot was probably the main factor in the decline of condors. The fact of the matter is, that bird species seem to vary widely in their response to DDT and its metabolites and other factors are important in the fate of many bird populations.So what are we to do in terms of policy about DDT? Perhaps the best answer we have on this issue, is this 1989 conclusion from the International Programme on Chemical Safety (IPCS)http://www.inchem.org/documents/ehc/ehc/ehc83.htm#SectionNumber:6.2"One of the most widely studied effects of DDT is eggshell thinningin birds, particularly in predatory species. The metabolite DDE, notDDT, has been shown to be responsible for this effect. Other effectson reproduction and survival of birds have been demonstrated. Largepopulation declines in birds of prey can be, at least partially,attributed to DDT. ...""Because of their lack of degradation, their resulting widespreadpersistence in the environment, their high acute toxicity to organismsat the base of food chains, and their high potential forbioaccumulation, DDT and its metabolites should be regarded as a majorhazard to the environment. DDT should not be used when an alternativeinsecticide is available."There may be some reason to consider DDT's limited use in malaria control as discussed here:http://pubs.acs.org/cen/government/84/8430gov1.html. However, the IPCS conclusions about DDT are still sound sound today. Indeed those interested in the controversy about the role of DDT in controlling Malaria should also see this article from the Washington Post.http://www.washingtonpost.com/wp-dyn/content/article/2005/06/04/AR2005060400130.htmlIn this article, entomologist May Berenbaum argues that DDT may have a limited role in managing malaria if mosquito populations can be monitored to assess the evolution of resistant strains but that we need to cut out the "overblown hype" about DDT. Perhaps this also applies to other aspects of the complex effects of man made chemicals on our environment.

Comments

Paul Decelles 7 years, 2 months ago

Exactly the point. Fortunately there are a number of cool methods under consideration that are likely to render the debate about DDT moot.

marjehecht 7 years, 2 months ago

The World Health Organization reversed its 30-year ban on DDT in September 2006, because it was clear that the so-called alternatives were failing to save lives, and that DDT was not harmful to human beings. Spraying minute amounts of DDT on the inside walls of houses once or twice a year continues to be a necessary tool in stopping the spread of malaria. DDT is more effective than other insecticides because it acts as a repellent; most mosquitoes, even those resistant to DDT, will not enter a house that has been sprayed inside.

DDT was banned for political reasons, not on the basis of science. Its ban was directed at population control. Alexander King, a co-founder of the Malthusian club of Rome, was forthright enough to say this. He commented that he had supported DDT use during World War II, but later regretted this, because its use had allowed population to flourish, instead of being killed off by malaria.

The Environmental Protection Agency held seven months of hearings on DDT in 1972, at the end of which the EPA hearing examiner, Edmund Sweeney, ruled that DDT should not be banned. You can read Sweeney's decision on the EPA web site, and excerpts of it on the website of 21st Century Science & Technology, www.21stcenturysciencetech.com .

There are also several articles posted on DDT, including one by entomologist J. Gordon Edwards on Rachel Carson's lies http://www.21stcenturysciencetech. com/articles/summ02/Carson.html

Another one with details on the use of DDT today is an interview with entomologist Donald Roberts http://www.21stcenturysciencetech.com/ 2006_articles/Donald_Roberts.pdf

The pros and cons of DDT unfortunately continue to be debated on the basis of ideology of one sort or another. Meanwhile, more than a million people die per year of malaria, and one child in Africa dies of malaria every 30 seconds. DDT isn't a magic bullet; nor is it a demon. It is a necessary part of a public health system that aims to saves lives.

Marjorie Mazel Hecht Managing Editor 21st Century Science & Technology

Paul Decelles 7 years, 2 months ago

The WHO did not say that DDT does not harm human beings:

Here is what the WHO REALLY says:

" DDT is one of 12 chemicals identified as a persistent organic pollutant that the Convention restricts. In May 2007, 147 countries were parties to the Convention. ...WHO actively sup- ports the promotion of chemical safety and, ..., shares a common commitment to the global goal of reducing and eventually eliminating the use of DDT while minimizing the burden of vector-borne diseases. "

Check out the WHO materials here: "http://www.who.int/malaria/ddtandmalariavectorcontrol.html

The following link might be of interest in spite of some glaring errors such as that DDT was instrumental in controlling Malaria in the United States. It was not. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1119118

As for Sweeny: here is what the EPA says:

"Immediately following the DDT prohibition by EPA, the pesticides industry and EDF filed appeals contesting the June order with several U.S. courts. Industry filed suit to nullify the EPA ruling while EDF sought to extend the prohibition to those few uses not covered by the order. The appeals were consolidated in the U.S. Court of Appeals for the District of Columbia.

On December 13, 1973, the Court ruled that there was "substantial evidence" in the record to support the EPA Administrator's ban on DDT."

http://www.epa.gov/history/topics/ddt/02.htm

DDT seems to have long term effects on cancer rates. See this report in the Washington Post http://www.washingtonpost.com/wp-dyn/content/article/2007/10/05/AR2007100502253.html?sid=ST2007100800983

Your leap of logic to the notion that banning DDT was some sort of perverse type of population control strikes me as absurd if it accurate certainly doesn't reflect anyone's thinking that I know and amounts to the worse sort of ideological mongering on par with which you accuse environmentalists of doing.

I do have to admit it is extremely difficult to cut through the ideological baggage about DDT. The Donald Roberts article is interesting but I find he repeats some of the same wild claims you make about population control.

For a balanced look at DDT which also cites Roberts by the way check out:

http://pubs.acs.org/subscribe/journals/esthag/41/i18/html/091507perspective.html

Interested readers might enjoy this look at the ideological thrust of some of the groups promoting DDT: http://www.sourcewatch.org/index.php?title=Malaria_and_DDT

I only bring this up to point out that there is plenty of ideological posturing on all sides of this issue.

Paul Decelles 7 years, 2 months ago

Thanks,

Also while DDT did have a role in the eradication of Malaria in the United States the CDC's graphs show clearly that Malaria was well in decline before the advent of DDT:

See http://www.cdc.gov/malaria/history/eradication_us.htm

and... http://www.ajph.org/cgi/reprint/94/10/1694.pdf

Be that as it may this whole controversy about DDT really seems to be a chance for ideological opponents to beat up on each other rather than actually dealing with the problem.

DDT may be appropriate for control of Malaria mosquitoes in some circumstances but it is a real stretch to extend that reasoning to West Nile.

Sounds like the Hoover Institute is engaging in a bit of fear mongering...the very thing they accuse environmentalists of doing....hmmm

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