1. KEY CONCEPT Pollution of Earth’s freshwater supply threatens habitat and health. Water is a renewable resource which could become nonrenewable in the near future.

2. Water pollution affects ecosystems.
Pollution can put entire freshwater ecosystems at risk.
Chemical contaminants such as fertilizers and pesticides, raw sewage, trash, animal wastes

3. Fertilizers can cause an algal bloom
Fertilizers can cause an algal bloom. Population explosion Reduces oxygen levels which can lead to the demise of the ecosystem. Ex. Red Tide (dinoflagellates) shellfish poisoning

4. Great Pacific Garbage Patch

5. Amphibians (frogs and salamanders) top predators
Indicator species (bioindicator) provide a sign of an ecosystem’s health. Aquatic indicators show the direct effects of pollution.
Amphibians (frogs and salamanders)
top predators
Discuss pollution in terms of the water cycle.

6. Biomagnification causes accumulation of toxins in the food chain.
Pollutants can move up the food chain.
Fat-soluble stays in body.
Water-soluble is excreted.
predators eat contaminated prey
pollution accumulates at each stage of the food chain
Top consumers, including humans, are most affected.
Ex. DDT (pesticide), mercury,
PCB’s, fluoride, boron, dioxins (measured in ppm).

8. Excerpts from 'Silent Spring’ Rachel Carson 1962
"These sprays, dusts and aerosols are now applied almost universally to farms, gardens, forests and homes -- non-selective chemicals that have the power to kill every insect, the "good" and the"bad"... Can anyone believe it is possible to lay down such a barrage of poisons on the surface of the earth without making it unfit for all life? They should not be called 'insecticides" but "biocides.'"
"All this is not to say there is no insect problem and no need of control. I am saying, rather, that ... the methods employed must be such that they do not destroy us along with the insects."
"We have subjected enormous numbers of people to contact with these poisons without their consent and often without their knowledge."
"It is ironic to think that man might determine his own future by something so seemingly trivial as the choice of an insect spray."
"Man is a part of nature, and his war against nature is inevitably a war against himself."
"In nature nothing exists alone.”
This was the start of the Environmental Movement. DDT banned in Lead to the development of the Environmental Protection Agency