Pesticides and theGREEN 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 food37% 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 Bhacropland: 1.5 Bha

A rab lelan d11 %

(1 .4 4 b illio nhec ta re s)

O the r land33 %

(4 .3 5 b illio nhec ta re s)

a

F orest and w ood land30 %

(3 .8 9 b illio nhec ta re s)

P e rm an en tm eado w s & p astu re s

26 %(3 .3 6 b illio n

hec ta re s)

17 % o f a rab le landis irriga ted(2 40 m illion h ec tare s)

The Earth's LandTotal Area: 13 Billion Hectares

a"Other land" includes barren and developed land.

Source: Food and Agriculture Organization

from Committee for the National Institute for theEnvironment

http://www.cnie.org/pop/conserving/landuse2.htm

[1] development of high yield strains of grains

[2] increased use of inorganic fertilizers

[3] irrigation[4] synthetic pesticide use

The green revolution:

increase productioneliminate competition

3 times more foodbeing produced

then in 1950

Are thereany

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 hydrocarbonsolvents

4. high toxicity to tissues

5. relatively low toxicity to humans

The idea ofBIOMAGNIFICATION

Fish are living separatory funnels

They ingest water containing DDT

The DDT dissolves in the fatty tissues of their bodies

Biomagnificationin 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

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. LD50 = (mass of DDT in rats) # Kg of rat