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 land growth: 0% per year

10% of Earth’s surface produces food 37% of Earth’s land produces food Total surface area of earth  5.1  m 2 Land  25%  1.3  m 2  13 Bha 10%  4.8 Bha (1 hm = 10 2 m; 1 ha = 1 hm 2 = 10 4 m 2 ) 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

[1] development of high yield strains of grains [2] increased use of inorganic fertilizers [3] irrigation [4] synthetic pesticide use The green revolution: increase production eliminate competition

3 times more food being produced then in 1950 Are there any environmental impacts?

Metabolic breakdown product, DDE:

Properties of DDT and other organic compounds 1. very stable 2. low stability in water 3. high stability in hydrocarbon solvents 4. high toxicity to tissues 5. 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 ppm [DDT] in plankton0.04 ppm [DDT] in minnows0.5 ppm [DDT] in needle fish2 ppm [DDT] in cormorants25 ppm

LD 50 A measure of toxicity 1. Feed DDT to rats (spike their food) 2. Continue upping their dose until half of the die 3. Measure concentration of DDT in the rats 4. LD 50 = (mass of DDT in rats) # Kg of rat