Transcript No Slide Title

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  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:
cropland:
3.3 Bha
1.5 Bha
The Earth's Land
Total Area: 13 Billion Hectares
Arable
land
11%
(1.44 billion
hectares)
Other landa
33%
(4.35 billion
hectares)
17% of arable land
is irrigated
(240 million hectares)
Permanent
meadows & pastures
26%
(3.36 billion
hectares)
Forest and woodland
30%
(3.89 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]
[2]
[3]
[4]
development of high yield
strains of grains
increased use of inorganic
fertilizers
irrigation
synthetic pesticide use
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
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