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Pesticides and the GREEN REVOLUTION can we feed the planet?. Since 1950 food grew faster than population: population growth: 1.7% per year food growth: 3% per year. 0% per year. land growth:. 10% of Earth’s surface produces food 37% of Earth’s land produces food
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Pesticides and the GREEN REVOLUTION can we feed the planet? Since 1950 food grew faster than population: population growth: 1.7% per year food growth: 3% per year 0% per year land growth:
10% of Earth’s surface produces food 37% of Earth’s land produces food Total surface area of earth 5.1 1014 m2 Land 25% 1.3 1014 m2 13 Bha 10% 4.8 Bha (1 hm = 102 m; 1 ha = 1 hm2 = 104 m2) pastures: 3.3 Bha cropland: 1.5 Bha
The Earth's Land Total Area: 13 Billion Hectares a"Other land" includes barren and developed land. Source: Food and Agriculture Organization from Committee for the National Institute for the Environment http://www.cnie.org/pop/conserving/landuse2.htm
The green revolution: [1] development of high yield strains of grains [2] increased use of inorganic fertilizers [3] irrigation [4] synthetic pesticide use increase production eliminate competition
3 times more food being produced then in 1950 Are there any environmental impacts?
Properties of DDT and other organic compounds very stable low stability in water high stability in hydrocarbonsolvents high toxicity to tissues relatively low toxicity to humans
The idea of BIOMAGNIFICATION
Fish are living separatory funnels They ingest water containing DDT The DDT dissolves in the fatty tissues of their bodies
Biomagnification in Long Island Sound [DDT] in sea water 0.000003 ppm [DDT] in plankton 0.04 ppm [DDT] in minnows 0.5 ppm [DDT] in needle fish 2 ppm [DDT] in cormorants 25 ppm
LD50 A measure of toxicity Feed DDT to rats (spike their food) Continue upping their dose until half of the die Measure concentration of DDT in the rats LD50 = (mass of DDT in rats) # Kg of rat