DDT, or dichlorodiphenyltrichloroethane, is a chemical compound that was first synthesized in 1874 and is an organochlorine insecticide. It was used to control malaria, typhus, body lice, and bubonic plague, and was a key element of malaria eradication in Italy and the United States. DDT acts upon the sodium ion channels in the neurons of insects, making them fire in a spontaneous manner, causing the insects to undergo spasms and eventually die. However, certain mutations in insects can make them resistant to DDT. DDT is a persistent organic pollutant that is readily adsorbed to soils and sediments, which can act both as sinks and as long-term sources of exposure affecting organisms.

DDT exposure can occur by eating, breathing, or touching products contaminated with DDT, and it can convert into DDE, which is a metabolite that persists in the body and environment. The body’s fatty tissues store DDT and DDE, and measurable amounts of DDT and DDE in serum do not imply that the levels of these chemicals cause an adverse health effect. However, biomonitoring studies of serum DDT and DDE provide physicians and public health officials with reference values to determine whether higher levels of DDT and DDE exposure in people are present than in the general population.

DDT was banned in the United States in 1972 due to its adverse environmental effects, such as those to wildlife, as well as its potential human health risks. DDT is known to act as an endocrine disruptor and is suspected to be a human carcinogen, although many studies suggest that it is not directly genotoxic. DDT is also believed to interfere with the regular thyroid function in pregnant women and has been linked to a higher risk of developing autism in children.