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Pesticides, diseases, and DDT. 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 ? What does ingestion and absorption mean?
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Pesticides, diseases, and DDT 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? 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 wastes Non- 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
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 DDT 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? What does ingestion and absorption mean? 4) What is one pro and one con for DDT?