Dichlorodiphenyltrichloroethane (DDT) Factsheet
Dichlorodiphenyltrichloroethane (DDT) is an insecticide used in agriculture. The United States banned the use of DDT in 1972. Some countries outside the United States still use DDT to control of mosquitoes that spread malaria. DDT and its related chemicals persist for a long time in the environment and in animal tissues.
DDT exposure in people
Exposure to DDT in people likely occurs from eating foods, including meat, fish, and dairy products. DDT exposure can occur by eating, breathing, or touching products contaminated with DDT. DDT can convert into DDE, and both persist in body and environment. In the body, DDT converts into several breakdown products called metabolites, including the metabolite dichlorodiphenyldichloroethene (DDE). The body’s fatty tissues store DDT and DDE. In pregnant women, DDT and DDE exposure can occur in the fetus. Both chemicals can be in breast milk, resulting in exposure to nursing infants.
How DDT Affects People’s Health
Human health effects from DDT at low environmental doses are unknown. Following exposure to high doses, human symptoms can include vomiting, tremors or shakiness, and seizures. Laboratory animal studies show DDT exposure can affect the liver and reproduction. DDT is a possible human carcinogen according to U.S. and International authorities.
Levels of DDT and DDE in the U.S. Population
CDC scientists measured DDT and its metabolite DDE in the serum (a clear part of blood) of 1,956 participants aged 12 years and older who took part in CDC’s National Health and Nutrition Examination Survey (NHANES) during 2003–2004. (National Report on Human Exposure to Environmental Chemicals and Updated Tables). By measuring DDT and DDE in the serum, scientists can estimate the amounts of these chemicals entering people’s bodies.
- A small portion of the population had measurable DDT. Most of the population had detectable DDE. DDE stays in the body longer than DDT, and DDE is an indicator of past exposure.
- Blood serum levels of DDT and DDE in the U.S. population appear to be five to ten times lower than levels found in smaller studies from the 1970s.
Finding measurable amounts of DDT and DDE in serum does not imply that the levels of these chemicals cause an adverse health effect. Biomonitoring studies of serum DDT and DDE provide physicians and public health officials with reference values. These reference values can determine whether higher levels of DDT and DDE exposure in people are present than in the general population. Biomonitoring data also help scientists plan and conduct research on exposure and health effects.