1. Science 10 Mr. Francis 5.3 – Bioaccumulation and Biomagnification

2. Key Concepts Many pollutants can bioaccumulate in organisms Biomagnification of pollutants can occur in organisms at the top of food chains / food webs

3. Bioaccumulation is the buildup of chemical substances within the tissues of organisms over time. Biomagnification occurs as you move up the food chain: small amounts of pollutants at the primary producer level can become lots at the tertiary consumer level

4. Biomagnification and Bioaccumulation 1000 particles of pesticide in each grasshopper Which means there are 400 particles of pesticide in each shrew Totalling 12,000 particles of pesticide in the owl

5. Pesticides Pesticides are anything we use to control pests. A pest is anything that we don’t want. A common pesticide was DDT (dichloro- diphynltrichloroethane) used to kill mosquitos.

6. DDT bioaccumulated in the bodies of organisms and biomagnified in each higher trophic level. A result was birds that could not reproduce due to fragile eggshells.

7. Not all pesticides bioaccumulate. Newer pesticides used today have short half-lives meaning they break apart after only a few hours and are no longer toxic to plants or animals.

8. Heavy metals are used in industry and are toxic or poisonous even at low levels. They are: Arsenic (As) Cadmium (Cd) Chromium (Cr) Copper (Cu) Lead (Pb) Mercury (Hg)

9. Mercury can be released into the atmosphere through burning coal. It is used in many devices that we use, even in our teeth! Bacteria convert mercury into another form which can be absorbed by plankton in the oceans. Mercury poisoning can cause paralysis.

10. Lead also bioaccumulates in our bodies. It used to be used for many household things like paint, pipes, and gasoline. It usually enters food chains through the air then eaten by consumers. Lead poisoning causes irreversible nervous system damage.

11. Many chemicals that bioaccumulate affect normal hormone function and are called EDC’s (endocrine disrupting compounds). These pretend to be natural hormones and impair normal reproduction and cause skeletal abnormalities.

12. Assignment Textbook page 125 Q 2, 3, 5, 6, 8, 10, 12