Science 9 - Pesticides

1
Pesticides
2
Pesticides

• Chemicals designed to kill pests which damage
  food crops
• Types of Pesticides include

Insecticides
Fungicide
Bactericide
Kills Insects
Kills Fungi
Kills Bacteria
3
Pesticides
4
(No Transcript)
5
Problem with Pesticides

• Some pesticides are
• Persistent not breaking down, staying active
• Fat Soluble get stored in the fat of living
  things

6
Bioaccumulation

• DEMO

7
Dangers of Pesticides

• Biomagnification
• Pesticides increases in concentration as you move
  up a food chain
• It occurs because toxins remain within the living
  tissue

8
Dangers of Pesticides

• Bioaccumulation
• The idea that more toxins gather and accumulate
  at higher trophic levels

9
Bioaccumulation
E.g DDT
10
Environmental Toxins
11
Mercury

• Most mercury from coal power-plants and waste
  incinirators
• Enters into atmosphere, but falls into lakes and
  oceans as methylmercury

12
Mercury
13
Mercury

• Methylmercury is a dangerous neurotoxin (brain
  killer)
• Eating contaminated fish results in higher
  chances of birth defects

14
Mercury
15
DDT

• A insecticide invented to kill insects (mainly
  mosquitoes)
• Used from 1839 until 1968, largely to prevent
  malaria

16
DDT
17
Malaria
18
(No Transcript)
19
DDT

• Problems
• Causes cancer and birth defects in humans
• Makes bird shells soft and fragile, therefore
  breaking easily

20
DDT
21
PCBs

• Used widely in glue, pesticides, wood sealants,
  and in electrical wiring until being banned in
  the late 1970s
• Toxin levels found in fish and birds
• Dangers
• Damages liver resulting in death
• In humans affects immune system, pregnancy, and
  reproduction

22
PCBs