DDT Dichlorodiphenyltrichloroethane

A brief history

Dichlorodiphenyltrichloroethane (DDT) is a pesticide that was first synthesized in 1874 by Othmar Zeidler. It wasn't initially advertised as a pesticide until after World War I, when it became one of the first chemicals in widespread use as pesticide. It was advertised to the public as the "wonder-chemical" that could defeat any pest problem, large or small. It was mass produced and used world wide. That was until 1972 when it was banned in most developed countries.

DDT on the Environment

As stated previously, DDT's was originally used as a pesticide. It was used to control mainly lice and mosquitoes. Its use slowed once these pest started to develop a resistance to the chemical. Once the insect's resistance began to build, there were no longer an benefits to using the chemical.

DDT was commonly used for agricultural purposes. It was spread throughout the fields to protect crops. The spread DDT would drain into aquatic systems, such as rivers, ponds, and lakes. The fish in the systems and the animals that lived off of them were greatly affected. The animal that was most greatly affect was the American Bald Eagle. The DDT in the fish the eagles would eat along with the contaminated water lead to health issues. The biggest concern being that their eggshells were thinning, which made reproduction an issue. Their population went down dramatically and the species is still recovering from this.

DDT's Effects on Humans

DDT is classified as a class 2 insecticide, meaning that it is moderately toxic. It is important to note that the main reason DDT was banned was due to its effects on human health. Low to moderate exposure to the compound could lead to nausea, diarrhea, irritation of the eyes, nose, or throat. High exposure could lead to tremors or convulsions.

The main concern came about when researchers found that DDT was staying in our bodies. It was found that during the 1950's, the prime DDT era, the average American was receiving .025 milligrams of the chemical a day. They were being exposed to it from contaminated fish and livestock. DDT deposits were mostly found in the thyroid, testes, and adrenals. There were small concentrations found within the liver and kidneys. DDT tends to stay in the fatty bodies in humans, so high concentrations of DDT were found in human milk. Those who were exposed to DDT occupationally suffered from chromosomal damage.

Importance of Understanding

It is important to understanding the key factors about DDT to protect ourselves and the environment. Understanding DDT and the problems that come about with using it can prevent the future use of it.

Chemical Side of DDT

  • Chemical Formula: C14H9Cl5
  • Molar mass 354.48 g·mol−1
  • Density 0.99 g/cm3
  • Melting point 108.5 °C (227.3 °F; 381.6 K)
  • Boiling point 260 °C (500 °F; 533 K) (decomposes)

Organic Grouping

DDT belongs to Alkyl Halide organic group.

Development

  • 1874: DDT was first synthesized by Othmar Zeidler under the supervision of Adolf von Baeyer.
  • 1934: The insecticide properties were described in a patent by Wolfgang von Leuthold
  • 1939: DDT's insecticidal properties were discovered by the Swiss scientist Paul Hermann Müller

Major ReActions

Formation

It is produced by the reaction of chloral (CCl3CHO) with chlorobenzene (C6H5Cl) in the presence of a sulfuric acid catalyst.

Insecticide

In insects, DDT opens sodium ion channels in neurons, causing them to fire spontaneously, which leads to spasms and eventual death. Insects with certain mutations in their sodium channel gene are resistant to DDT and similar insecticides.

Common Uses

  • Used by the military in WW II to control malaria, typhus, body lice, and bubonic plague
  • Pesticide for insect control in the United States (canceled in 1972 by the EPA)

Works Cited

"DDT - A Brief History and Status." EPA. Environmental Protection Agency, 22 Nov. 2016. Web. 16 Mar. 2017.

"The DDT Story." Pesticide Action Network. N.p., n.d. Web. 16 Mar. 2017.

"DDT'S EFFECTS ON THE EARTH AND HUMANS." DDT's Effects on the Environment and Humans. N.p., n.d. Web. 16 Mar. 2017.

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