2.  Pests are organisms that live in areas where they are not wanted. They cause harm to crops, people or animals.  Pesticides can help rid the areas of these pests. A pesticide is a chemical substance, biological agent (such as a virus or bacteria), antimicrobial, disinfectant or device used against any pest

3.  Pesticides are among the most widely used chemicals in the world, and also among the most dangerous to human health.

4.  They are a leading cause of poisonings in Canada and have been estimated to account for thousands deaths each year globally. Pesticides are not only man- made, but also occur in nature

5.  There is evidence that pesticides play a role in human cancers. For example, epidemiological studies have linked exposure to insecticides in the home to development of brain cancer and leukemia in children.  Studies have also documented reproductive abnormalities such as an increased rate of miscarriage in people with chronic exposure to pesticides.

6.  Because of the health hazards associated with pesticides, alternative methods are being developed that decrease the need to use pesticides.  Pest-resistant crops (genetically modified organisms) are being used to decrease the need for pesticides.

8.  Biomagnification, also known as bioamplification, or biological magnification is the increase in concentration of a substance, usually a pollutant like the pesticide DDT or the element mercury, in a food chain.

9.  The chemical usually enters the food chain through the producer, or first trophic level. The producer absorbs the chemical and stores it in its tissues.

10.  The producer is then eaten. As you know, the primary consumer needs a great deal of producers to meet its energy requirement. So along with the organism's nutritional needs, the herbivore consumes the pollutant and stores it in its tissues.

11.  When the secondary consumer eats the herbivore, it obtains and stores even more of the pollutant, so that the organisms at the top of the food chain are ingesting huge quantities of the pollutant.

12.  Therefore the quantity of the pollutant is magnified as it moves up the trophic levels.

13.  Bioaccumulation: a slow build up of chemicals in the bodies of organisms  Eg. bioaccumulation of PCBs in the B.C. Orcas. PCBs will affect the reproductive cycles of Orcas until at least 2030, even though they were banned in ‘77.