Biomagnification

1. Biomagnification

2. Biomagnification • Biomagnification, also known as bioamplification or biological magnification, is the increase in concentration of a substance, such as the pesticide DDT, that occurs in a food chain as a consequence of: • Persistence • Food chain energetics • Low rate of internal degradation/excretion of the substance (often due to water-insolubility)

3. Mercury • Minamata a disease or neurological syndrome caused by severe mercury poisoning. • Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, narrowing of the field of vision and damage to hearing and speech. In extreme cases, insanity, paralysis, coma and death follow within weeks of the onset of symptoms

4. Mercury case study • Humans generally uptake mercury in two ways: • As methylmercury (CH3Hg+) from fish consumption, OR • By breathing vaporous mercury (Hg0) emitted from various sources such as metallic mercury, dental amalgams, and ambient air. • Our bodies are much more adapted for reducing the potential toxicity effects from vaporous mercury, so health effects from this source are relatively rare.

6. Biomagnification • So what is happening because methylmercury (CH3Hg+) is Persistent meaning it can not be broken down through natural process it moves up the food chain. • At each level in the food chain there is a greater concentration, because it is not broken down at the lower levels.

8. Other things which Biomagnify • DDT’s which are a pesticide which use to be used all the time. It was later found out it Biomagnifies up the food chain and makes bird eggs soft. The use stopped in most industrialized countries after a large environmental movement.

9. DDT’s still in use • Some countries with large pest problems and little money still use DDT’s • Do you think this is right?