1. Biomagnification

2. Consequences of pyramids and ecosystem function
The concentration of toxic substances in food chains
The limited length of food chains
The vulnerability of top carnivores

3. Bioaccumulation
Bioaccumulation: Toxics build up in an organism over time
Chemicals that break down slowly or not at all
Materials that are not excreted
Examples: DDT, POPs, Mercury

4. Biomagnification
Biomagnification: Concentration of toxin increases up a food chain
Any consumer eats many individuals from the level below, acquiring all of toxins
Concentration may not affect lower trophic levels

5. Top Carnivores
Polar Bears and Seals have been found with pesticides in their tissues even though they were thousands of miles away from areas of use.
Biomagnification of DDT caused egg shell thinning
Top carnivores have a limited diet
Their numbers are already low because of energy transfer efficiency
Top carnivores are often
keystone species

6. Minamata Bay
Chisso Factory produced a variety of petro based substances
Fertilizer, plastics, etc.
Methyl Mercury was being slowly released into the bay from 1932 to 1968!
Estimated 24 tonnes
Beginning in the 1950s…
Minamata Disease