1. Bioaccumulation and Biomagnification

2. Bioaccumulation This is the way materials become concentrated in the tissues of a living organism. Biomagnification This is the way substances become concentrated in living things as the substance moves through a food chain. (up trophic levels)

3. Bioaccumulation This is the process by which pollutants are absorbed and stored in living org’s. Chronic exposure over long periods may lead to bioaccumulation. Initial exposure may have been to concentrations too low to cause problems but accumulation of pollutant may result in poisoning

4. Bioaccumulation This is the process of the accumulation of materials in living things. Bioaccumulation occurs when the rate at which the material is absorbed and stored in the organism is faster than the rate at which it is removed. Removal may be through excretion or because of the breakdown of the substance.

5. Bioaccumulation cont’d Liposoluble pollutants tend to build up in lipid stores... Water soluble pollutants tend to be excreted more easily. Chlorinated organic compounds (eg organochlorine insecticides, dioxins and PCBs and heavy metals all bioaccumulate. dioxin

7. Biomagnification This is the concentration of pollutants that bioaccumulate as a result of them passing up trophic levels. Pollutants that bioaccumulate in one organism are eaten by predators, and as large quantities of prey are eaten over a long time the pollutant becomes increasingly concentrated.

9. The mercury concentration in the tissues of the tuna is....

11. The more trophic levels there are in a food chain the.....

12. Biomagnification of DDT

15. Biomagnification http://techalive.mtu.edu/meec/module02/FoodChain.html

16. Synergism Substances act synergistically when their combined affect is greater than the sum of their individual affects e.g. the synergy between oxides of nitrogen and sulphur dioxide Also their is a synergistic affect between zinc and cadmium

17. Mutagenicity Substances or forms of energy that cause changes to DNA are termed mutagens The effect of a mutagen depends not only on the extent of the damage to DNA but also depends on the type of cells that are affected PCBs, dioxins, asbestos and ionising radiation

18. Carcinogenicity Any substance that can cause cancer is termed a carcinogen. These are mutagens that affect normal tissue growth Cadmium, asbestos, DDT, carbon tetrachloride and many more!

20. Teratogenicity Teratogens are substances that can cause birth defects without altering DNA They work by disrupting normal development Mercury and the herbicide 2,4,5T are examples of pollutant teratogens