Debate over the use of DDT to control malaria is likely to continue. However, over the past several decades, much has been learned about how this insecticide works, and why its extensive use poses an environmental concern

Question

Discuss three characteristics of this chemical that cause it to be problematic.

Answer 1

DDT is a synthetic chemical, developed in the mid-1940s as an insecticide to be used against malaria. This chemical has many of the critical characteristics that cause it to be particularly harmful to a wide array of warm-blooded organisms, including humans. Its persistence, transport in the environment, and uptake by many non-target organisms contribute significantly to its environmental health concerns. DDT is not easily broken down in the environment, and even its by-products are toxic. DDT's environmental persistence is estimated to vary between 30 and 100 years. Because it is sprayed over wide areas, it easily gets into water supplies and affects aquatic food webs. Because it is taken up by insects and other small organisms found in lower trophic levels, its ability to bioaccumulate in higher organisms in the food chain is dependent on its fat solubility characteristic. That is, DDT is able to be stored in the tissues of living organisms without breaking down, and this characteristic leads to its biomagnification in the food web. Organisms that feed on other organisms whose tissues have stored DDT, are likely to store an even higher concentration. Some of the most well-documented environmental effects of DDT have been egg-shell thinning in birds of prey; however, cancer and developmental abnormalities have also been documented in amphibians and other higher vertebrates.