Pesticides, diseases, and DDT1) What are two ways chemicals get into the environment?
b) What is the difference between persistent and non-persistent?
2) What is the difference between pesticides, herbicides, and insecticides?
3) What does ingestion and absorption mean?
4) What is one pro and one con for DDT?
Looking at this photo: How are chemicals getting into our water system?
Types of wastesNon- persistent: Will break down by natural ways in the environment. Ex) sewage
Persistent: Will not break down in the environment very easily. Ex) DDT, mercury
Pesticides
Pesticide: Herbicides Insecticides
What they control plants insects
Example pests Weeds Mosquitoes
Example pesticides Roundup DDT
DDT
• Dichlorodiphenyltrichloroethane
… We’ll just call it DDT
DDT
- Used in WWII to exterminate lice.
PRO
DDT: Lice/Typhus- The lice carried the disease typhus, which cause devastating effects, sometimes even death, on the soldiers.
PRO
DDT: Mosquitoes/ malaria- Mosquitoes carry malaria, which causes your red blood cells to burst open. This means they can no longer carry oxygen.
PRO
Pros of DDT:
- In African countries, the use of DDT caused a drop of malaria from 70% to 5% in just 6 years.
PRO
How DDT gets into organisms
Ingestion: eat it. Digestive system
Inhalation: Breath it in. Respiratory system
Absorption: absorbed through the skin. Circulatory system
Evidence against DDT-It has a half-life of 12 years. Meaning it does not leave the environment for many many generations.
- It is fat-soluble meaning it dissolves into fat stores and stays in organisms for decades.
CON
Peregrine Falcon-Stops the flow of calcium from mother to eggs. This meant the eggs were not at thick and strong as they should be.- These brittle eggs would break, resulting in less falcons making it to adulthood.- These birds almost went extinct
CON
DDT: collects in the food chain- As DDT moves up the food chain. More of it collects in the fat stores of animals.
Biomagnification
- Build up of substances, such as pesticides, in an organism.
- It is being absorbed faster than the substance is lost.
DDT debate
• Life-saving or life-threatening?
Pesticides, diseases, and DDT1) What are two ways chemicals get into the environment?
b) What is the difference between persistent and non-persistent?
2) What is the difference between pesticides, herbicides, and insecticides?
3) What does ingestion and absorption mean?
4) What is one pro and one con for DDT?
