A Bug Doctor Educational Moment: DDT

The following excerpts are presented to you from credible sources (cited below) and set in order to briefly tell the DDT story. I have set them this way because it would take the average reader several hours to glean all the different websites to gain this perspective. It did for me anyway.

Perhaps some of this information is new to you, perhaps you had no idea of the scope and magnitude of a simple observation and how many lives it would save- how many it ‘could’ve saved’ except for another set of observations.

The story of DDT and its demise should be something we should learn from, however, I don’t believe we have and I doubt if we ever truly will.

DDT (dichlorodiphenyltrichloroethane)

DDT does not occur naturally but is produced by the reaction of chloral (CCl3CHO) with chlorobenzene (C6H5Cl) in the presence of sulfuric acid as a catalyst.

First synthesized in 1874, but its insecticidal action was discovered by the Swiss chemist Paul Hermann Muller in 1939.

DDT came into use during World War II, and in a very short time saved more lives and prevented more diseases than any other man-made chemical in history.

The product was such a boon to public health that in 1948 the Nobel Prize in Physiology or Medicine was awarded to Dr. Paul Müller for his discovery of the “contact insecticidal action” of DDT.

Malaria is a preventable mosquito-borne disease. — Malaria claims one million lives every year.

The National Academy of Sciences concluded in 1965 that ‘in a little more than two decades, DDT has prevented 500 million [human] deaths that would otherwise have been inevitable.

Sixty million people have died needlessly of malaria, since the imposition of the 1972 ban on DDT, and hundreds of millions more have suffered from this debilitating disease.

It can be controlled by spraying a tiny amount of DDT on the walls of houses twice a year.

DDT is cheaper than other pesticides, more effective, and not harmful to human beings or animals.

It costs only $1.44 per year to spray one house with DDT. The more toxic substitutes cost as much as 10 to 20 times more and require more frequent applications, making spraying programs prohibitively expensive. In addition, replacement pesticides have to be applied more frequently and are more toxic.

Another advantage of DDT is that even when mosquitoes become resistant to its killing effects, they are still repelled by it. This effect is known as “excito-repellency.”

A study by the Harvard University Center for International Development estimated that a high incidence of malaria reduces economic growth by 1.3 percentage points each year. Compounded over the four decades since the first bans of DDT, that lost growth has made some of the world’s poorest countries an astonishing 40 percent poorer than had there been more effective mosquito control.

India is the only country still manufacturing DDT, India is the largest consumer as well.

In Ceylon (now Sri Lanka) DDT spraying had reduced malaria cases from 2.8 million in 1948 to 17 in 1963. After spraying was stopped in 1964, malaria cases began to rise again and reached 2.5 million in 1969.

The chief malaria expert for the U.S. Agency for International Development said that malaria would have been 98 percent eradicated had DDT continued to be used.

A comparison of the annual Audubon Christmas Bird Counts between 1941 (pre-DDT) and 1960 (after DDT’s use had waned) reveals that at least 26 different kinds of birds became more numerous during those decades, the period of greatest DDT usage.

As recently as 1998 researchers reported that thrush eggshells in Great Britain had been thinning at a steady rate 47 years before DDT hit the market.

Human volunteers have ingested as much as 35 milligrams of it a day for nearly two years and suffered no adverse effects.

DDT is poorly absorbed through the mammalian skin, but it is easily absorbed through an insect’s outer covering known as an exoskeleton.

DDT is highly persistent in the environment. The soil half-life for DDT is from 2 to 15 years.

The half-life of DDT in an aquatic environment is about 150 years.

As early as the 1940s, scientists in the U.S. had begun expressing concern over possible hazards associated with DDT, and in the 1950s the government began tightening some of the regulations governing its use. However, these early events received little attention, and it was not until 1957 when theNew York Times reported an unsuccessful struggle to restrict DDT use in Nassau county, New York, that the issue came to the attention of the popular naturalist-author, Rachael Carson. William Shawn, the editor of The New Yorker, urged her to write a piece on the subject, which developed into her famous bookSilent Spring, published in 1962.

The year after it appeared, President Kennedy ordered his Science Advisory Committee to investigate Carson’s claims.

Carson, who was diagnosed with breast cancer in 1957, lived only two years after Silent Spring was published.

The EPA then held seven months of hearings in 1971–1972, with scientists giving evidence both for and against the use of DDT. In the summer of 1972, the cancellation was announced for most uses of DDT.

Every major scientific organization in the world supported DDT use, submitted testimony, as did the environmentalist opposition. The hearings went on for seven months and generated 9,000 pages of testimony. Hearing Examiner Sweeney then ruled that DDT should not be banned, based on the scientific evidence: “DDT is not carcinogenic, mutagenic, or teratogenic to man [and] these uses of DDT do not have a deleterious effect on fish, birds, wildlife, or estuarine organisms,” Sweeney concluded.

Two months later, without even reading the testimony or attending the hearings, EPA administrator William Ruckelshaus overruled the EPA hearing officer and banned DDT. He later admitted that he made the decision for “political” reasons. “Science, along with economics, has a role to play . .. .. [but] the ultimate decision remains political,” Ruckelshaus said.

A worldwide ban on its agricultural use was later formalized under the Stockholm Convention.

In September 2006, the World Health Organization (WHO) declared its support for the indoor use of DDT in African countries where malaria remains a major health problem, citing that benefits of the pesticide outweigh the health and environmental risks. The WHO position is consistent with the Stockholm Convention on POPs, which bans DDT for all uses except for malaria control.








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