1. Air and Water Chapter 5 Section 2 The Water Supply

2. Main Ideas Most of Earth’s water – about 97% is salt water. Most of Earth’s water – about 97% is salt water. People and many other organisms require fresh water to carry out their life processes. People and many other organisms require fresh water to carry out their life processes. Although there are some natural sources of water pollution, most pollution is the result of human activities. Agriculture, industry, construction, and mining all produce wastes that can end up in water. Although there are some natural sources of water pollution, most pollution is the result of human activities. Agriculture, industry, construction, and mining all produce wastes that can end up in water.

3. Water a Limited Supply ¾ of the fresh water on Earth is in the form of ice. ¾ of the fresh water on Earth is in the form of ice. Many areas do not have fresh water available to them. They draw their water from hundreds of kilometers away. Many areas do not have fresh water available to them. They draw their water from hundreds of kilometers away.

5. Most fresh water is located in ice caps

6. Key Terms Groundwater: Water stored in underground layers of soil and rock. Groundwater: Water stored in underground layers of soil and rock. Drought: A period of less rain than normal. Drought: A period of less rain than normal. Water pollution: A change to water that has a harmful effect. Water pollution: A change to water that has a harmful effect. Sewage: The water and human wastes that are washed down sinks and toilets Sewage: The water and human wastes that are washed down sinks and toilets Fertilizer: A chemical that provides nutrients to help crops grow better. Fertilizer: A chemical that provides nutrients to help crops grow better. Pesticide: A chemical that kills crop=destroying organisms. Pesticide: A chemical that kills crop=destroying organisms. Sediments: Particles of rocks and sand. Sediments: Particles of rocks and sand.

7. Water Pollution Water Pollution is any change to water that has a harmful effect on people or other living organisms. Water Pollution is any change to water that has a harmful effect on people or other living organisms. Even treated sewage can pollute. Even treated sewage can pollute. Fertilizers and Pesticides can pollute nearby waters such as rivers. Fertilizers and Pesticides can pollute nearby waters such as rivers.

8. Sewage System

9. Review Why isn’t most of the water on Earth’s surface available for people to use? Why isn’t most of the water on Earth’s surface available for people to use? Most water on Earth is salty, and much of the fresh water is ice. Most water on Earth is salty, and much of the fresh water is ice. Name four types of human activities that can be sources of water pollution. Name four types of human activities that can be sources of water pollution. Agriculture, industry, construction, mining. Agriculture, industry, construction, mining.

10. Review Why can finding the source of water pollution be difficult? Why can finding the source of water pollution be difficult? The source can be far from the pollution. Pollutants can dissolve and move throughout a body of water. Sources can be hidden underground. The source can be far from the pollution. Pollutants can dissolve and move throughout a body of water. Sources can be hidden underground. What is sewage? Why should it be treated before being released into the environment? What is sewage? Why should it be treated before being released into the environment? Sewage is the water and human wastes that are washed down sinks and toilets. It contains disease causing organisms that can mix with water used for drinking or swimming, and make people ill. Sewage is the water and human wastes that are washed down sinks and toilets. It contains disease causing organisms that can mix with water used for drinking or swimming, and make people ill.