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Toxicants may accumulate in the food chain

Toxicants may accumulate in the food chain. Some toxicants are not easily broken down in the body and build up in the body Some substances are stored in fat or muscle tissue Bioaccumulation refers to the process where toxicants build up in an organisms.

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Toxicants may accumulate in the food chain

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  1. Toxicants may accumulate in the food chain • Some toxicants are not easily broken down in the body and build up in the body • Some substances are stored in fat or muscle tissue • Bioaccumulation refers to the process where toxicants build up in an organisms

  2. Toxicants may accumulate in the food chain • Biomagnification occurs when the concentration of toxicants increases each step up the food chain • Ex) the most famous example of this occurred with DDT into birds; this caused many species of birds in the US to decline

  3. Case study on pesticides: Bhopal, India • On December 3, 1984 the world’s worst industrial accident occurred at a Union Carbide pesticide plant • An underground storage tank exploded and released a large quantity of toxic gas used to produce pesticides • 600,000 people were exposed and at least 22,000 died • The company was found to be at fault

  4. Dose Response Curves • Sometimes, a response only occurs above a certain dose, the threshold dose • This occurs when the body can metabolize or excrete toxins until they are overwhelmed at high doses

  5. Dose Response Curves

  6. Dose Response Curves • The LD50 is the amount of toxicant it takes to kill half the population of study animals • A high LD50 indicates low toxicity and a low LD50 indicates high toxicity

  7. Dose Response Curves • The LD50 is the amount of toxicant it takes to kill half the population of study animals • A high LD50 indicates low toxicity and a low LD50 indicates high toxicity

  8. Questions • LD 50 • LD 75 • LD 25

  9. Question 7 • chemical A has an LD 50 of 7, and chemical B has an LD50 of 20. Which is more toxic?

  10. Question 8

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