1. TONIGHTS HW – SCIENCE IV (Brown book) Read p48-51 Q’s 1,2,3abc,4,5,9

2. Things that cause pollution Fertilizers – (N,P,K) organic, inorganic Pesticides – herbicides, insecticides, fungicides Sewage – organic and inorganic components Toxic Substances from landfills and industry

3. Pesticides Chemicals that are designed to kill pests Pests – are any organism that people consider harmful or inconvenient As early as 500 B.C. chemicals like Sulfur were used to kill crop eating pests. Today almost 2.3 million tons of pesticides are used yearly. This is about.4 kg per person.

4. Problems with Pesticides Can enter the food chain by being eaten directly or through runoff Move through the food chain as organisms eat each other Take a long time to break down Can be fat soluble not water soluble (stay in the body) Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species Can cause birth defects and cancer in humans

5. Biomagnification (Bioamplification) The build up of toxic chemicals through successive trophic levels in the food chain The most effected animals are at the top of the food chain.

6. Example DDT

7. EXAMPLE MERCURY

8. In order for a pollutant to biomagnify, the following conditions must be met: The pollutant must be “long-lived”. And can not be broken down easily. Why? The pollutant must be concentrated by producers. (Bioaccumulation) Why? The pollutant must be fat-soluble. Why?