Pesticides

1. Pesticides What are they? DDT The advantages The disadvantages Biomagnification By Nasser Alsharif 9M

2. Pesticides are chemicals used by farmers to kill various pests. Pests are insects, fungus, bacteria and other things that feed on crops, are vectors for disease, nuisances, and things that destroy property. The basically compete with us for the crops. Farming is a big business and some companies will do anything for profit, pesticides and genetically modified organisms are how they insure that they will get the crop yield they demand every season, no matter what the consequences. Pesticides are sprayed on the crops, so they can take effect and kill the pests when they try to eat the crops.

3. The Advantages of Pesticides Pesticides allow farmers to produce a greater yield each season. This means that more produce is available in markets and, due to the rules of supply and demand, it will be cheaper. The crops also grow bigger, better and most likely each crop will produce more fruits, seeds, etc… Pesticides also ensure that when we buy an apple, for example, we won’t find a worm buried inside it, that vegetables we buy won’t have holes in them where pests have eaten.

4. The Disadvantages of Pesticides Pesticides can contribute to air pollution . Pesticide drift is when pesticides suspended in the air as particles are carried by wind to other areas, potentially contaminating them. Pesticides that are sprayed on crops can be blown by the wind into nearby areas, potentially posing a threat to the wildlife. Nitrogen fixation, which is when plants take in nitrogen from the air and convert it into a usable form, is hindered by pesticides. This prevents plants from getting all the nitrogen they need. If the use of pesticides is reduced then the world could save $10 billion in synthetic nitrogen based fertilizer every year. Pesticide can be hazardous to Aquatic Life and can pollute drinking water when it is washed of into water bodies.

6. DDT DDT is one of the world’s most well known synthetic pesticides. It was first introduced in the early-to-mid 1900s. DDT was used extensively during World War II by the Allies to control the rapid spread of typhus by killing off insects carrying the disease. It was also used in the South Pacific to control the spread of Malaria. DDT was viewed as a savior back then but nowadays we are questioning whether it was a wise decision to release such tremendous amounts of this chemical without knowing exactly how it could effect the environment and us humans. DDT is toxic to a wide range of animals, not only insects, such as marine animals and many species of fish. It is less toxic to mammals, but may be moderately toxic to some amphibian species

8. Biomagnification Biomagnification (also known as bio amplification) is the increase of the concentration of a substance, DDT in this case, in a food chain.It can be caused by when the substance can’t be broken down, easily or at all, by natural processes or by the consumers digestive systems. DDT is a substance of that type; it can’t be broken down easily by animals in a food chain. DDT in water bodies is eaten by organisms living under the water such as fish, which in turn are eaten by large birds, animals or humans. The substances become more concentrated in the bodies of the different organisms as you move up the food chain. The high concentrations of DDT have had a large impact on the population of predatory birds, interfering with their reproductive organs and causing the eggs they lay to have thin shells that crack during incubation.

9. PPM = parts per million

10. Credits • Information from: • http://en.wikipedia.org/wiki/Environmental_effects_of_pesticides • http://en.wikipedia.org/wiki/Biomagnification • http://www.globalhealingcenter.com/effects-of-pesticides.html • http://en.wikipedia.org/wiki/DDT I hope you enjoyed the presentation and now have a better understanding on this topic  By Nasser Alsharif 9M