Was DDT of More Harm Than Use

DDT is an abbreviation of the old name of the compound 4,4 -dichlorodiphenyl-trichloroethane. It was first prepared by Austrian chemist Othmar Zeidler (1859 -1911) in 1874, its insecticide potential was only discovered 60 years later in the systematic studies of Swiss chemist Paul Hermann Muller (1899-1965), who was awarded the 1948 Nobel Prize in Physiology or Medicine for his insights. 

Commercial DDT contains several active ingredients about 77 % of the 4,4 -isomer (hence, it is often called DDT, which might cause confusion as the mixture is also marketed under the same name), 15 % of the 2,4 -isomer, and the remaining 2 % is DDE and DDD (Fig. 4.8). DDT affects neurons it dismpts the normal functions of sodium ion channels at the receptors of neurotransmitters. The channels cannot close properly, so neurons remain in an excited state for a prolonged time, which seriously disturbs motor functions and senses. Insects are more sensitive to DDT than mammals, and because mammals also detoxify their bodies more efficiently, the initial observations did not show any adverse side effects. 

The debate about carcinogenicity barely faded away when the first reports appeared decrying the damaging effects of pesticides on the human immune system. Many experts urged the increased use of immunotoxicological testing in pesticide approval processes. 

The history of DDT is not a simple one, but it has been further complicated by the rather extreme human reaction that began to tirm against its use (Fig. 4.9). The silent spring envisioned by Carson has never arrived, the frightening conclusiorts of the book were indeed imfoimded (critics say outright erroneous). Carson and her followers also share some responsibility for helping to develop public chemophobia 1.1) and encoitrage a hysterical approach toward chemicals. 

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DDT is an acronym for dichlorodiphenyl trichloroethane, but should be named more precisely as 2,2-bis(p-chlorophenyl)-l,l,l-trichloroethane (see Fig. 16.1 for its structure). A German chemist, Othmar Zeidler synthesized this compound in 1874 while he was pursuing his PhD. And it had remained as that, a new synthesized compound, for a quite while. Carl Muller of J. R. Geigy (a Swiss Pharmaceutical company, now Chiba-Geigy) discovered in his pursuit of insecticides that the compound synthesized by O. Zeidler was extremely toxic to houseflies. Numerous tests were conducted, and the compound DDT was found to be an excellent insecticide. Besides it is cheap to make. This was the time when the World War II was raging. DDT was then used to control lice on soldiers on the front. In earlier wars, more soldiers died of typhus (bom by louse) than by bullets. The WWII was really the first war in history where more soldiers died actually from bullets than the louse-bom disease, thanks to DDT. DDT was then considered to be a savior to control many kinds of harmful pests. C. Muller was awarded a Nobel prize in 1948. 

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