Leo Ramirez
March 10, 2013
Chemistry 105
DDT
Dichloro-diphenyl-trichloroethane (DDT) is a man-made molecule, synthetized in 1874 but its properties were not discovered until 1939. Its properties were discovered just in time to be used in the second half of World War II. Paul Hermann Müller was awarded the Nobel Prize in physiology and medicine for this discover. After World War II, it was used as an insecticide.
DDT is a mixture of related compounds and the major compound is p, p’isomer. Dichlorodiphenyldichoroethylene (DDE) and Dichlorodiphenyldichloroethane (DDD) make up the balance and they are also the major metabolites and breakdown products in the environment.
In 1962, an American biologist, Rachel Carson, wrote a book that talked about the environmental impacts of DDT for its indiscriminate use in the USA. This led to DDT being banned in the USA in 1972. After being banned in the USA, it was also banned worldwide for agricultural use. The impact was not only to the environment but to humans also. Although there are not many arguments or studies of the impacts on humans, some of the existing studies have found some diseases including reduced fertility, genital birth defects, breast cancer, diabetes, damage to developing brains, chronic liver damage, chronic hepatitis, immune suppression, and cytogenic effects. DDE can block male hormones. In South Africa, it has been used for about 60 years and is still being used to control malaria and it has caused damage in babies because of contaminated milk. "Unfortunately the smallest children are exposed to the highest DDT levels; they are also extra sensitive to chemical influence," Kylin says (ScienceDaily 2012).

DDT is a man-made chemical; it is an organochlorine insecticide. Its physical properties make DDT a unique molecule. The picture shows its structural formula. The molecular formula contains 14 carbons, 9 hydrogen’s and 5 chlorines (C14H9Cl5). Its color is white, it is a crystalline solid, it has no taste and is almost odorless. DDT is insoluble in water but soluble in fats and oils. Its boiling point is 185°C and it has a density of 1.016 kg/L at 20°C.
In War World II, DDT was used to control Malaria and Typhus that attacked not only soldiers but civilians. The way they did it was through spray.
It was a very common chemical after War World II. It was spread worldwide and was being used in agricultural activities as an insecticide. It was also used to kill any kind of bacteria or disinfectant. DDT is still used in South America, Africa, and Asia for the same purpose. In the United States, it is still manufactured but is sold to or used only by foreign countries. According to studies, 1.8 million tons have been produced all around the world. In the US, 600,000 tons were used before the 1972 ban (Wikipedia). Since its discovery, it has been the ideal chemical agent because of its effectiveness killing any type of insect. Some researchers working in Africa say that they have found a replacement for DDT. Its name is microencapsulated chlorpyrifos-methyl (CS) and it is just as effective as DDT.
Other chemicals like methoxychlor have been used after DDT but they have not been as effective as DDT. Also chemicals like Borax Powder and boric acid are being used but still not as effective as DDT.
There has been a controversy among scientists for its use. They have been questioning whether it is worse than malaria. DDT is very soluble in fat, which means it is easy to get into the human body and cause health problems like previously mentioned. It can be very helpful in an epidemic emergency but can also be very dangerous if used indiscriminate. Malaria remains as a public health problem in many countries. In 2008, there were approximately 243 million cases and 863,000 deaths. Most of these deaths occurred in Africa; it killed mostly children less than 5 years of age. In humans, the half- life of DDT is 6 to 10 years and during this time, it can cause enormous damages to the body. A test conducted in 2008 in the United States by Center for Disease Control, showed that DDT was present in all blood samples. After its indiscriminate use, if left disastrous impacts on the environment. Since it is soluble in fats and oils, it also finds its way to get into any type of living organism and the most affected of all of these is the one on top of the food chain (human). In 2007, at least 3,950 tons of DDT was sprayed for mosquito control in Africa and Asia, according to a report by the United Nations Environment Programme (Marla Cone 2009).
Depending on the half-life of soil and conditions, DDT ranges from 22 days to 30 years. Due to its hydrophobic properties, it is absorbed by aquatic organisms, leaving little DDT absorbed in water.
DDT is also lipophilic. Therefore, it can accumulate in fats and oils; accumulation occurs mostly in body fat. The most affected are birds. DDT and DDE make the birds’ eggs thin by making them break, killing the embryo. Studies show that predator birds are more affected than other animals in the same environment (Wikipedia). It was the cause of the decline of the Bald Eagle in the United States. After it was banned, the Bald Eagle came back In conclusion, DDT has properties that make it unique compared to the rest of the chemical compounds. These properties make it a very dangerous compound to both humans and the environment. There is concern among people who know what DDT is and how it affects nature and the human health. It can be also be a good tool to use in case of an epidemic attack but should be restricted to only those that know how to use it properly without putting human life at risk. Since DDT is lipophilic, it is easy to get into body fat and stay there for years and cause fatal diseases. It should be kept away from living organisms if its use is needed. Living organisms have oil and fat that can absorb DDT, for instance plants. It gets to the roots and is spread to its fruit, which will be eaten later either by humans or animals. We cannot blame anybody for inappropriate use in the past. There was a need and people had to make a choice between letting their family die or use DDT to kill the problem. Now we have a more advanced science that can use other methods to solve these types of situations. I chose this molecule because it is related to my field of study (environmental science) and because I wanted to be aware of the damages it causes on the environment and humans. I also chose DDT because it was suggested by my professor, Dr. Sherpa.

Works Cited ScienceDaily. March 8, 2013, http://www.sciencedaily.com/releases/2012/09/120903142949.htm Wikipedia, March 5, 2013, http://en.wikipedia.org/wiki/DDT. Marla Cone and Environmental Health News, March 8, 2013, http://www.scientificamerican.com/article.cfm?id=ddt-use-to-combat-malaria. Dr. Nida Besbelli, Poison Center, March 8, 2013, 206203. http://www.inchem.org/documents/pims/chemical/pim127.htm. Hank Lacey, March 10, 2013, http://www.examiner.com/article/researchers-say-they-ve- found-a-ddt-replacement.