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[Michaelangelica]

DDT is the totemic baddy of the green movement
http://www.spiked-online.com/Articles/000000005591.htm
DDT is the totemic baddy of the green movement. Suspicions about it caused the first green crusade, inspired by Rachel Carson's Silent Spring nearly 40 years ago. When it was used in vast quantities in agriculture, DDT probably harmed reproduction in birds of prey - but this harm subsequently proved reversible.

After 50 years of study there is not one replicated study that shows any harm to humans at all. And DDT is now only used for vector control, and is only sprayed inside houses. Dr Amir Attaran from Harvard University estimates that the amount of DDT used to spray a few acres of cotton in the USA in the early 1960s would spray all the homes in Guyana of those at risk of malaria - and that such indoor spraying will have 'negligible impacts on the environment'.

Despite the evidence, Greenpeace militants have been protesting to close down DDT's only major production facility in the world, in Cochin, India. The Indian government has given its assurance to Greenpeace that production will cease from 2005. But fortunately, India's National Anti-Malaria Programme has objected to this commitment, because it has used DDT to control vectors since it began its operations in 1953. The government may make an embarrassing but essential U-turn.

In South Africa the government stopped using DDT in 1996 - and since then malaria rates have risen by around 1000 percent, because mosquitoes are becoming resistant to the new generation of pesticides. The parasite that causes malaria is also becoming resistant to drug treatments - and out of sheer desperation, South Africa has returned to using DDT.

http://www.pan-uk.org/pestnews/actives/ddt.htm:

Human exposure
Analysis of human fat has been carried out occasionally in the UK showing that DDT can persist for many years. Analysis of 203 samples of mostly renal fat showed 99% contained detectable residues of DDT (see table 3)(24). Many of the levels found are above effect-level exposures required to elicit a carcinogenic response in test animals (see mice studies above). They are also well above the life-time safety exposure limit ADI of 0.02 mg/kg body weight.
Table 3. DDT* residues of in human fat (1995-1997) mg/kg (for UK)
No. of cases level
47 1.0 - 9.3
135 0.1 - 0.9
19 0.01 - 0.09
2 not found
* p,p'-DDT, o,p'-DDT, o,p'-TDE, and p,p'-DDE

Once stored in fatty tissue, DDT residues are sequestrated and stabilised unless they are mobilised either through lactation or significant weight loss, which burns fat. Organochlorines appear to transfer freely across the placenta from mother to foetus.
In one study involving humans, 17 people ate 35 mg/man daily (about 0.5 mg/kg daily) for 18 months suffering no ill-effect(25). In another study volunteers ate 0.31 to 0.61 mg/kg daily without any noticeable effects(26).
Residue values tend to be higher for older people. According to John Wargo of Yale University in the US, children under the age of 14 have roughly one-third the level of those over 45, and African-Americans experience levels roughly three times those of whites for corresponding age classes. It is unclear whether the differences for African-Americans are due to a variation in environmental exposure, or because of genetic differences(27).
DDT is excreted in human milk. A study carried out in Zimbabwe found high levels of DDE residues in breast milk commonly exceeded those required to cause hyporeflexia in infants(28).
Between 1950 and 1970 DDT was used over large areas of the Soviet Union. As a result, dangerously high residue levels were found in both food and human tissue(29).
DDT is found in the bodies of people living in the Arctic regions, where DDT has never been used. Along the west coast of Greenland, in Nunavik, Canada, and in Nikel on the Lola Peninsula of Russia, blood levels are only a factor of ten lower than the levels that are known to cause neurological effects in babies(30).
Levels of p,p-DDT in the UK have reduced significantly since the mid 1960s. This would be expected, as DDT has not been approved since 1984. Levels of the breakdown product p,p'-DDE are not coming down so quickly. Although the average figure has more than halved, the range has not changed much since the mid 1960's, and has even increased compared with the early 1970s and early 1980s figures(31).

Ecological effects
Environmental fate
DDT and its breakdown products have widespread persistence in the environment, and a high potential to bioaccumulate. It has a reported half-life in the environment of 2-15 years in most soils(32).
Many governmental and inter-governmental organisations regard DDT as a major hazard to the environment(33).

Fish
DDT is highly toxic to fish. The 96-hour LC50 (the concentration at which 50% of a test population die) ranges from 1.5 mg/litre for the largemouth bass to 56 mg/litre for guppy. Smaller fish are more susceptible than larger ones of the same species. An increase in temperature decreases the toxicity of DDT to fish(34).

Birds
DDT and its metabolites can lower the reproductive rate of birds by causing eggshell thinning which leads to egg breakage, causing embryo deaths. Sensitivity to DDT varies considerably according to species(35). Predatory birds are the most sensitive. In the US, the bald eagle nearly became extinct because of environmental exposure to DDT. According to research by the World Wildlife Fund and the US EPA, birds in remote locations can be affected by DDT contamination. Albatross in the Midway islands of the mid-Pacific Ocean show classic signs of exposure to organochlorine chemicals, including deformed embryos, eggshell thinning and a 3% reduction in nest productivity. Researchers found levels of DDT in adults, chicks and eggs nearly as high as levels found in bald eagles from the North American Great Lakes(36).

Developing countries
A recent overview of organochlorine use in Africa during the last 25 years concluded that continued use has led to serious problems for wildlife in terms of uptake into the tissues of many animals groups, particularly birds, with potential long-term adverse population effects(37).

Endocrine disrupters
DDT, DDD and DDE are all strongly suspected of being environmental endocrine disrupters (chemicals that affect the hormonal system). DDT can have reproductive endocrine effects (see above) and also has a major toxic effect on the adrenal glands. DDT-related deformities in birds include clubbed feet and crossed bills. There is also concern that it has the potential to disrupt the endocrine system of humans(38).
Resistance
Many insect species have developed resistance to DDT. The first cases of resistant flies were known to scientists as early as 1947, although this was not widely reported at the time(39). In the intervening years, resistance problems increased mostly because of over-use in agriculture. By 1984 a world survey showed that 233 species, mostly insects, were resistant to DDT(40). Today, with cross resistance to several insecticides, it is difficult to obtain accurate figures on the situation regarding the number of pest species resistant to DDT.

Global contamination
DDT is one of nine persistent organic pollutants (POPs) which bioaccumulate, and which are transported by air and water currents from warmer climates to temperate zones, where they have never been used. The process of degradation is dramatically slowed down in cooler climates. The global risk of adverse effects to human health and the environment has led the international community to mandate the UN Environment Programme (UNEP) to convene an intergovernmental negotiating committee (INC) for a POPs Convention to phase out production and use. The first INC meeting takes place in June 1998. This action endorses the recommendations of the Inter-governmental Forum on Chemical Safety (IFCS) Ad Hoc Working Group on POPs(41 ,42).

An yet the pro lobby says
http://reason.com/hod/rb112900.shtml

Conclusion
There is widespread global contamination of DDT. It is a hazard to the environment, both are areas where it is still used, and in many regions thousands of miles away where it is no longer, or never has been used. As a matter of urgency the use of DDT, a major POP, needs to be phased out

"The scientific literature does not contain even one peer-reviewed, independently replicated study linking DDT exposures to any adverse health outcome" in humans, says Amir Attaran. "No study in the scientific literature has shown DDT to be the cause of any human health problem," concludes Richard Tren and Roger Bate in When Politics Kill: Malaria and the DDT Story, a new study from the Competitive Enterprise Institute.

Such facts have failed to undermine environmentalist dogma. "Because Carson’s work led to the ban on DDT," Al Gore concluded in his commemorative introduction to Silent Spring, "It may be that the human species…or at least countless human lives, will be saved because of the words she wrote."

Sadly, it's more likely that, because a blinkered orthodoxy cannot accept the heretical notion that DDT has some beneficial purposes, countless human lives will be lost.

http://reason.com/hod/rb112900.shtml


http://www.iwmi.cgiar.org/pubs/working/WOR95.pdf

3.2.2 Cost-effectiveness of DDT
Malaria control decision makers who use or want to use DDT to combat malaria say they want to use it because it is both effective and inexpensive, when compared to alternatives. With budgetary constraints faced by the Ministries of Health, these decision makers find it necessary to use the least expensive option for vector control.
However, none of the malaria control or insecticide control specialists in Ethiopia, Uganda, Kenya or South Africa could cite a formal cost-effectiveness
study to assess whether IRS using DDT was, in truth, the most effective and inexpensive method to be used.
Several researchers have conducted cost-effectiveness analyses for DDT and its alternatives and found varying results. In KwaZulu-Natal, South Africa, IRS using pyrethroids was the most cost-effective vector control option when compared to insecticide treated bed nets (DDT was not considered in this study) (Goodman et al. 2001).
In contrast, cost comparisons in western Thailand
and the Solomon Islands indicated that ITNs were more cost-effective control measures than IRS using DDT (Kamolratanakul 2001; Kere 1992).
Kathleen Walker concluded in her global cost comparison of DDT to its alternatives that although globally the cost of DDT was lower than its alternatives (as of 2000), “a global cost comparison may not realistically reflect local costs or effective application dosages at the country level”: she goes on to say that “the most cost-effective insecticide in any given country or region must be determined on a case-by-case basis” (Walker
2000).
In light of her conclusion and the diversity of results in cost-effectiveness studies, it is surprising that certain countries have assumed that DDT is the most cost-effective alternative.
Ideally, cost-effectiveness studies should aid malaria vector control decision-making.
Unfortunately, many countries lack the capacity necessary to obtain and analyze data for such studies.
Among other countries,3 Ethiopia and South Africa are participating in a WHO/UNEP study funded by the Global Environment Facility (GEF) to “assess cost-effectiveness and sustainability of environmentally sound and locally appropriate alternatives to DDT” (UNE/WHO Project Brief).