Guided Notes on the Human Impact on Water Resources Chapter 27, Section 4

Compare and contrast point sources and nonpoint sources of pollution:  Point sources generate pollution from a single source of origin, such as a septic tank  Nonpoint sources generate pollution from widely spread areas, such as acid precipitation

2. Rainwater dissolves pesticides and fertilizers and carries them into streams as it drains farms and lawns. Runoff from roads and parking lots containing oil, gasoline, and chemicals is another nonpoint source of pollution.

3. 50% of the U.S. population lives near coastlines, and pollutants from such cities often end up in estuaries and near-shore regions.

How does sewage water create dead zones on the ocean floor?  The high levels of nitrogen and phosphorus in sewage create blooms of cyanobacteria that later die and use up oxygen in the water as they decompose.

5. It is much cheaper and more efficient to prevent pollution than it is to clean it up later.

6. Since 1972, the number of people served by sewage-treatment plants has increased, while the annual rate of wetland losses has decreased. This is a sign that the Clean Water Act is working.

7. Water conservation is the most common solution to excessive demand. Efficient irrigation practices can greatly reduce the demand for water.