1. (c) McGraw Hill Ryerson 2007 12.3 Water Quality and Its Effects on Living Things Human activities are having many negative impacts on the water cycle. See page 454

2. Water Quality and Its Effect on Living Things We are adding far too many waste materials to the water system, and many wastes that do not break down quickly or efficiently. We are removing far more water from natural sources than the water cycle can naturally replace. Human demands for fresh drinking water and industrial water supplies increase every year. (c) McGraw Hill Ryerson 2007

3. Sources of Water Pollution Pollution = materials harmful to the environment. Point source pollutants  Point sources of pollution refer to locations that can be directly traced as the source of a pollutant entering the environment.  Examples include oil spills, waste-water pipes emptying into rivers, or a landfill leak into the groundwater. See page 455 - 456

4. Sources of Water Pollution Non-Point source pollutants  Non-point sources of pollutions come from many sources, and cannot be traced back to one single source. This makes them very difficult to control.  Examples include run-off from industry, dog parks and farms.  Groundwater is very susceptible, since it can be contaminated for hundreds of years. (c) McGraw Hill Ryerson 2007

5. The Effects of Water Pollution Humans have large demands for water, but we also are responsible for endangering its quality.  chemical - acid rain, pollutants  physical - oil spills, hydro projects  biological - bacteria, wastes See page 457 - 458 The remains of this albatross chick show how plastics can affect marine life.

6. The Effects of Water Pollution Oceans cannot decompose the large amounts of wastes, or their toxicity, that enters primarily along coastal areas. Plastics decompose over thousands of years, and can cause great damage to wildlife. (c) McGraw Hill Ryerson 2007

7. Oil pollution in oceans comes primarily from non-point sources such as people changing oil in their cars and pouring the used oil down the drain. Oil spills from tankers can be tragic, but occur infrequently. Small spills from pleasure craft and smaller boats add a constant, high-volume of pollution to the marine environment. The Effects of Water Pollution See pages 457 - 458

8. Acid Precipitation Acid precipitation contaminates all bodies of water.  The main sources of acid precipitation are nitrogen oxides and sulfur dioxides from the burning of fossil fuels. Burning coal, gas and oil is a primary source of energy.  Nitric acid and sulfuric acid are produced, and fall as acid precipitation (c) McGraw Hill Ryerson 2007

9. Acid Precipitation Water is naturally acidic, but the acidity increases from acid precipitation. This + other pollutants then enter the groundwater, fresh water and salt water environments. See page 459 - 460 Take the Section 12.1 - 12.3 Quiz