DDT Not Just A Wrestling Move

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1 Josue Perez 14 March, 2014 C151 DDT Not Just A Wrestling Move DDT is a wrestling move named after a chemical with the same acronym. The move is performed by putting ones opponent in a front facing headlock, and then falling backward while pushing the opponent s legs causing them to flip over, driving the opponent s face in to the ground. What kind of chemical would be so deadly to have a wresting move named after it, and stranger still this chemical would win a Noble prize in physiology, and yet years later it gain so much infamy years latter for its damage to the environment. DDT stands for dichlorodiphenyl-trichloroethane (Fig.1). DDT was a pesticide that was used to curve the Fig 1. The shape of DDT spread of malaria and other diseases during and after WWII. Years later, it was be band in many countries due to its adverse effects on the environment and was one of the reason for starting the environmental movement in the United States. DDT was first synthesized in a laboratory in 1873; but it was not until 1939 that Dr. Paul Muller discovered its effectiveness at killing insects. Muller spent years trying to find chemicals that would kill insects, but would not harm humans. In the past, the only way of fighting against insects was to use insecticides that were poisonous to both humans and insects. Through his research Muller discovered that mammals did not easily absorb DDT through their skin, but insects did. For his discovery Muller was awarded the Noble prize in Physiology in 1939(8). Developed in the 1940 s as one of the first modern class of synthetic insecticides that pose no serious threat to humans but deadly to insects. Soon the insecticide was used in WWII; first in Europe as a means of fighting against typhoid spreading insects with great success. Then it was adopted in the South Pacific to use against malaria caring mosquitoes. The use of DDT played an important role in the war by keeping soldiers and civilians safe from diseases. After the war, DDT continued to be use for commercial farming in America. DDT made an ideal insecticide for agricultural use due to its low cost; low-toxicity to humans; and its long lasting quality meant that DDT did not have to be used as often. Further more, many countries used it as a way to fight against malaria and other diseases. The use of DDT helped lower the mount of malaria from 400,000 in 1946 to almost zero in 1950, proving to many countries that the wide spread of DDT through the land would be beneficial (7). Not only that but malaria was almost all wiped out in American and

2 Europe. Unfortunately many of the physical and chemical properties were still unknown the only thing that was known was that it was cheap easy to produce, and that it had a long life span that it did not have to be used as much. With its relatively low lethality to humans it made it ideal for areal spraying by planes, which also lead to the wide spread of DDT through out the environment. By the end of 1970s more than 1.3 billion pounds of DDT were used in America (1). Soon though many of its negative effects started to appear as the years went on. After careful studies it was discovered that DDT worked by disrupting the nervous system in insects. The nervous system of insects worked by controlling the flow of sodium and potassium out of the nervous cells which then messaged the muscles to relax or tensing the muscles. DDT s carbon that is connected to a single hydrogen plays the most important role in disrupting the nervous system. When the nervous cells open up their ion channels to release the sodium ions the single hydrogen on the carbon enters the channel and keeps the channel from closing. By keeping the ion channel open and allowing the sodium to flow out of the nerve cell makes the muscles unable to relax which causes muscles to spasm, which leads to death in insects. For a while it was believed that DDT was only harmful to insects, but at the time many were unaware of some animals ability to metabolize DDT in to DDE. DDE has almost the same shape as DDT except that it is missing one hydrogen, which makes the carbon chain in to an ethane (fig. 2). Although DDE is still not very toxic to organisms themselves, DDE has the ability to interfere with enzymes in animals, primarily birds, that controlled calcium distribution, which resulted in fragile eggshells, making it hard for birds to raise their young due to eggs always breaking when birds sit on them to keep them warm (2). Once the DDE entered the body of birds the adults birds themselves are unharmed, but without the ability to raise healthy newborns, the populations of birds became stagnate. The small change in the shape of the molecule did not alter the physical properties; its non-polar quality gave DDE an even more sinister ability of being soluble in lipid fats, which meant that it would stay inside an organism s fat body tissue for years. Once the adult birds have all died there wouldn t be any younger generation that would replace the old generations, which would lead to a sudden disappearance of birds from the area without a single warning. This event would latter go on to be known as the silent spring a phrase coined by Rachel Carson. In 1962 Rachel Carson published The Silent Spring, a book where she detailed all the negative effects of DDT and other pesticides had on the wildlife populations in North America; and refers to DDT as elixir of death. The tittle of the book referred to an event where one day all of the birds would disappear without a warning. Many of the

claims made by the book were already known; in 1945 the Fish and Wildlife Service had detriment that DDT made considerable damage to wildlife, beneficial insect, and indirectly to crops, (2) but that

3 claims made by the book were already known; in 1945 the Fish and Wildlife Service had detriment that DDT made considerable damage to wildlife, beneficial insect, and indirectly to crops, (2) but that fact did not matter much to the public. The book had both a social change in the American public who started to become more aware of the negative effects humans have on the environment, and a political. Soon John Kennedy ordered his Science Advisory to investigate the claims made by the book. After the Science Advisory the Environmental Defense Fund was created in to investigate and review the usage of pesticides (3). Year later the Environmental Protection Agency was created in 1970 which worked to band the substance in 1972 in America. Many of the physical properties of the DDT made it an ideal chemical to use as an insecticide. One of the features is its low vapor pressure, allowing it to last longer. Having no ionic charger also makes it extremely insoluble in water, meaning that it can t be washed away by rain or water. Finally, it is extremely stable that it is unreactive with almost everything. These factors allowed DDT to protect ones crops for weeks, months or even years. Unfortunately the qualities that made it extremely stable meant that once the environment was exposed it would last in the environment for many years to come. Since the initial band of DDT, the EPA has ben studying the concentration of DDT in the environment. The chart below shows a concentration drop of DDT since its initial ban. Since 1969the EPA has been studying the concentration of DDT in the environment. (9) Even if the amount of DDT concentration would decrease to almost negligible amounts, DDT would still pose a threat to birds, through something know as bio magnification. Bio magnification is the increase of toxicity in a species the farther up the food chin one goes; this is cause by small animals that are at the bottom of the food chain

4 are unaffected due to the low amount of DDT concentration in the water, but as predators eat many of these small creature the percent of toxicity in the animals increase, until it reaches the top of the food chains where the apex predators have a high percentage of toxicity. This affects mostly apex animals, usually birds of pray and even humans. With bio magnification DDT can still have great environmental effects even when the concentration is low. There has been lots of criticism about Rachel Carson s Silent Spring; many have accused her of exaggerating the negative effects DDT has on humans and the environment. Many claim that Caron s book is nothing more than a puff piece, and flawed science with antidotal evidence and is nothing more than a crusade to vilify DDT (4). Some people go as far as to unjustly blame Rachel Carson for the death of millions of people who have died from malaria due to the banning of DDT. When comparing the negative effects of malaria are far worse than those of DDT Carson s opponents would argue that the benefits of DDT outweigh the negatives. The World Health organization estimates that in 2012 more than 600,000 deaths were cause by malaria (5), mostly in Africa. Although DDT is band in almost all western countries, many countries through out the world still use DDT as a means of controlling and preventing the spread of malaria. Government that chose to use DDT don t use it cause they are ignorant of the negative effects on environment or cause they are willfully evil, but because the consequences of not using DDT out weighted the negative effects on the environment. When a country decides to use pesticides to combat malaria, DDT is usually the best choice due to its low cost, and its long lasting effectiveness means it only has to be applied every few months. Further more the effects of DDT on the environment can be reduce by only indoor residual spraying; where only the inside and around windows and door ways of building are sprayed (5). When sprayed indoor DDT is effective for 9-12 months (5). Although some insect have become resistant to the effects of DDT; DDT still repeals them and only the effectiveness is reduced not its ability to kill insects. DDT is prime examples of the apposing views people have about pesticides; some people would cast DDT as nothing more than a poison that ruins the environment, but others would say that it is important tool that can save peoples lives. Even Rachel Caron never advocate the complete banning of DDT, but rather that DDT should be carefully used in a controlled fashion. That is why pesticides should not be viewed as evil or good but as a tool; a tool that each society should weigh the consequences to determine whether or not to use them. 1 DDT- A Brief History and Status. Environmental Protective Agency. 12 Feb < 2. DDT and other Organichlorine Insecticides. Fish and wildlife. Web. 12 Feb < 3. Physical and Chemical Properties people.chem.duke.edu. Web. 12 Feb <

5 4. Miller, Henry. Conko, Gregory. Rachel Carson s Deadly Fantasies. Forbes. Web. 12 Feb < 5 Malaria: key facts. World Health Organization. Web. 15 Feb < 7 DDT. National Pesticide information center. Web. 12 Feb. 2014< 8. The Nobel Prize in Physiology or Medicine Nobelprize.org.Nobel Media AB Web. 10 Mar 2014 < 9. Pesticides in the Nation s Streams and Ground Water, U.S. Geological Survy. < Web. 10 Mar. 2014

From VOA Learning English, this is SCIENCE IN THE NEWS. I m June Simms.

From VOA Learning English, this is SCIENCE IN THE NEWS. I m June Simms. And I m Bob Doughty. Today we tell about a new animal species native to South America. We tell how agricultural chemical products