Point-source Pollution and Dissolved Oxygen

Answer the following questions about the Dissolved Oxygen Depletion curve.

1. Give three examples of point-source pollution that could be coming from the pipe illustrated in the decomposition zone, use page 284 to help you answer.

2. What type of pollutants are commonly found in from the point-sources you listed?

3. What units are used to report dissolved oxygen?

4. What happens to dissolved oxygen in the decomposition zone? What happens to biochemical oxygen demand in the decomposition zone?

5. How do changes in DO and BOD in the decomposition zone affect the number species present in the water? How do the changes affect the types of species found in the decomposition zone?

6. What types of species are found in the water when dissolved oxygen is 2ppm? 8ppm?

7. What happens to biochemical oxygen demand in the septic zone? What do you think causes this change? 

8. What happens to dissolved oxygen in the recovery zone? What is the relationship between dissolved oxygen and biochemical oxygen demand? 

9. Trout, perch, and bass are indicator species. What do you think these species tell us about the water quality in lake, stream or river?

10. Thermal pollution is a point-source pollutant, commonly found near power plants which discharge cooling water. Draw the following table on your paper, and fill the data from the overhead as I demonstrate the affect of thermal pollution on dissolved oxygen.

Temperature	Dissolved Oxygen

 11. Graph the change in temperature and dissolved oxygen over time. Make sure you use different colors to indicate DO and temperature.