Bioaccumulation Flashcards
What is DDT, and what was its original purpose?
DDT is an insecticide used since the 1940s to kill insects that transmit diseases like malaria and typhus and to protect crops from pests.
Why did people initially believe DDT was safe?
They thought it only harmed insects and did not consider its effects on other organisms or the environment.
Who raised awareness about the dangers of DDT, and how?
Rachel Carson, through her 1962 book Silent Spring, explained how DDT was killing not only insects but also birds and harming the environment.
Who raised awareness about the dangers of DDT, and how?
Rachel Carson, through her 1962 book Silent Spring, explained how DDT was killing not only insects but also birds and harming the environment.
What does “persistent chemical” mean in relation to DDT?
It means DDT does not break down and remains in the environment for many years, even resisting decomposition.
How does DDT spread in the environment?
When sprayed, DDT can be carried into the air and transported long distances from where it was applied.
What happens to DDT in an animal’s body?
DDT stays in the animal’s body for its entire life, as it does not break down.
How does DDT harm birds?
It makes their eggshells thin and fragile, causing them to break before hatching.
What did the photograph in the text show regarding DDT’s impact on birds?
It showed broken eggs of an ibis bird, which could not hatch because the female had DDT in her body.
What is biomagnification?
Biomagnification is the process where the concentration of a chemical, like DDT, increases as it moves up the food chain.
How does DDT enter the food chain in water ecosystems?
DDT is sprayed into water to kill mosquito larvae. Tiny single-celled protists absorb the DDT, starting the chain.
How many times greater is the concentration of DDT in a cormorant than in a minnow?
The concentration in a cormorant is 52.8 times greater than in a minnow (26.40 ÷ 0.50).
Why is the concentration of DDT higher in cormorants than in minnows?
Cormorants eat many minnows, accumulating all the DDT stored in the minnows’ bodies over time. This process amplifies the concentration at higher trophic levels.
