If DDT was banned in the 1960s, why is it still an environmental concern today?
1 Answer
While DDT was banned in 1960s, it is a very persistent chemical.
Explanation:
While DDT, or dichloro-diphenyl-trichloroethane, was banned in 1960s, it is a very persistent chemical. The ban on DDT in the United States went into effect in 1972 (see a timeline of events here).
DDT used decades ago can still be found in the atmosphere, the soil, and even snow. The half-life of DDT in soil can be decades. While we're not producing DDT regularly anymore, we still have to worry about the DDT stored in the soil.
DDT bioaccumulates and is stored in fatty tissues. It leaves these tissues at a very slow pace.
DDT is absorbed by plants, which are eaten by fish, which are eaten by predatory fish, which are eaten by humans and other animals. All the while, DDT leaves these animals and plants at a very slow rate, meaning the chemical accumulates as we go up the food chain:
