What is DDT?

Dichlorodiphenyltrichloroethane or DDT, is a synthetic pesticide. It was largely used to control common agricultural pests.

Pros and Cons of DDT

As previously mentioned, DDT was used in agriculture. In addition, it was used extensively during the 1950s to the 1960s to control various types of diseases, such as typhus and malaria. Malaria control measures significantly improve community health. Thus, DDT has not been banned because in regions where there is a extensive use of DDT, especially tropical regions, an outright ban would have greater negative consequences than continuing to use it.

As shown by the graph above, DDT was successful at containing malaria in Japan.

Effects of DDT on living organisms


While DDT was initially highly successful at containing diseases, it also had major drawbacks. Ecologically, significantly reducing or eliminating a particular species would cause a dramatic change in the entire ecosystem. Moreover, a side effect of DDT is bioaccumulation, which occurs when an organism absorbs a toxic substance at a rate greater than that at which the substance is lost. Despite its ability to contain diseases, bioaccumulation has brought extensive damage to organisms and declines in wildlife populations.

Effects of DDT on humans


DDT is believed to be potentially carcinogenic (cancer-causing), and in reviewing the human health effects of DDT exposure, it has been observed that DDT is related to conditions such as Type 2 diabetes, blood hormone levels, birth mass, a type of pancreatic cancer, and fertility. Also, it was concluded that exposures are often high in areas where DDT is applied in dwellings, and breast milk levels often exceed tolerable daily intakes recommended by agencies such as the World Health Organization.

Past efforts regarding DDT


The organization that we got in touch with was the US Environmental Protection Agency. In the early 1970s in the United States, all DDT products were cancelled because of concerns about carcinogenicity, bioaccumulation, biomagnification in food chains, and hazard to wildlife, and other chronic effects. As a response to this, regulatory actions were laid down by the US Environmental Protection Agency, including:
Pesticide Registration Notice 71-1, January 15, 1971 and 37 Federal Register 13369, July 7, 1971.
Regarding alternatives, the USEPA strongly recommended integrated pest management, also known as IPM. IPM programs rely on consideration of all alternatives before deciding on the best course of action. IPM was a science based approach to managing pests that considers the biology of the crop and the pest, without bringing much harm to either of them. It relies on pest identification, monitoring for pests, and identifying the levels of infestation that can be tolerated without causing unacceptable harm.

Ways to reduce the harmful effects of DDT
While DDT is a necessity in agriculture, it is a primary concern that human exposure be kept at a minimum. Many alternatives exist in which all the benefits of DDT enjoyed, while avoiding its negative effects. Our contact in India has pointed out that commercial DDT contains two separate DDT isomers, one being endocrine-active, as well as other components. It is possible, according to our source, that the endocrine-active isomer be removed while retaining its anti-malaria properties, thus effectively eliminating the negative side effects of DDT. Another suggestion was to implement changes in the application procedure of DDT as well as using  risk management policies, which in the long run will greatly reduce human exposure to DDT's as well as limit the harmful effects it has on pregnant mothers, breast-feeding mothers, babies, and toddlers. Finding a safer alternative to DDT would prove advantageous in the long run.

The World Health Assembly, WHO's governing body, has stated that countries should reduce reliance on insecticides for controlling malaria by promoting integrated vector management and other measures, and that DDT should be used only within such an integrated approach. 

Alternatives include;

• case detection and treatment with drugs
• control of mosquito larva by chemical and non-chemical methods
• use of chemical substitutes for spraying houses
• and distribution of bed nets treated with alternative chemicals

Until all nations can transition to effective and affordable alternatives, appropriate mechanisms are necessary to ensure that human health is not compromised as reliance on DDT is reduced.