Bioaccumulation and Biomagnification Animation 2

How DDT Moves Through the Food Chain

DDT is a toxic pesticide that builds up in organisms and becomes more concentrated at higher levels of the food chain.

Bioaccumulation and Biomagnification

Bioaccumulation occurs when an organism absorbs DDT and it builds up in its tissues over time. Even when DDT concentrations in marsh water are low, plankton can take it in.

Small fish accumulate larger doses by eating many plankton. Larger fish accumulate still more DDT by eating smaller fish. Birds that eat fish, such as herons, can receive the highest doses because they consume many contaminated fish throughout their lives.

The increasing concentration of a toxic substance at successively higher levels of the food chain is called biological magnification, or biomagnification. The video says DDT levels in body tissues can increase by more than 100,000-fold from plankton to birds, and links this effect to drastic declines in several predatory bird populations.

Speakers and Sources

• Narrator: An unnamed voice explains the process in an educational animation.
• Other speakers: None identified.