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Bioaccumulation and Biomagnification

Bioaccumulation and Biomagnification. Bioaccumulation vs. Biomagnification. Bioaccumulation: The increase in concentration of a substance in an organism over time (taken in and stored faster than they are broken down) Biomagnification :

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Bioaccumulation and Biomagnification

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  1. Bioaccumulation and Biomagnification

  2. Bioaccumulation vs.Biomagnification • Bioaccumulation: • The increase in concentration of a substance in an organism over time (taken in and stored faster than they are broken down) • Biomagnification: • The increase in concentration of a pollutant from one link in the food chain to another

  3. Properties of substances that bioaccumulate • The substancemust be: • Long lived • Mobile • Fat soluble (typically) • Biologically active Can you think of situation where bioaccumulation is positive?

  4. A Classic Example: DDT • DDT – dichloro-dipheny-trichloroethane (chlorinated hydrocarbon) • It has a half-life of 15 years – that means if 100 kg of DDT is used it will break down as follows:

  5. So, after 100 years, there will still be over a pound of DDT in the environment!

  6. DDT (cont’d) • DDT has rather low toxicity to humans • But • high toxicity to insects • If accidentally swallowed in large amounts, it can cause a person to become excitable, have tremors and seizures • In animals, harmful effects in reproduction and in the nervous system • Causes shell-thinning in birds, in particular carnivorous birds (raptors) such as ospreys and bald eagles

  7. Biomagnification of DDT

  8. Biomagnification of Other Pollutants

  9. Biomagnification of Mercury

  10. Rachel Carson • "Man's attitude toward nature is today critically important simply because we have now acquired a fateful power to alter and destroy nature. But man is a part of nature, and his war against nature is inevitably a war against himself…[We are] challenged as mankind has never been challenged before to prove our maturity and our mastery, not of nature, but of ourselves."

  11. Movie • http://www.biocourse.com/mhhe/bcc/resources/concept.xsp?id=000012091&type=MOVIE

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