Air and Water Chapter 5Air and Water Chapter 5Section 2Section 2

The Water The Water SupplySupply

Main IdeasMain 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 People and many other organisms require fresh water to carry out their life processes.water to carry out their life processes.

Although there are some natural sources of water Although there are some natural sources of water pollution, most pollution is the result of human pollution, most pollution is the result of human activities. Agriculture, industry, construction, and activities. Agriculture, industry, construction, and mining all produce wastes that can end up in mining all produce wastes that can end up in water.water.

Water a Limited SupplyWater a Limited Supply

¾ of the fresh water on Earth is in ¾ of the fresh water on Earth is in the form of ice.the form of ice.

Many areas do not have fresh water Many areas do not have fresh water available to them. They draw their available to them. They draw their water from hundreds of kilometers water from hundreds of kilometers away.away.

Most fresh water is located in ice Most fresh water is located in ice capscaps

Key TermsKey Terms

Groundwater: Water stored in underground layers of soil Groundwater: Water stored in underground layers of soil and rock.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 Water pollution: A change to water that has a harmful

effect.effect. Sewage: The water and human wastes that are washed Sewage: The water and human wastes that are washed

down sinks and toiletsdown sinks and toilets Fertilizer: A chemical that provides nutrients to help crops Fertilizer: A chemical that provides nutrients to help crops

grow better.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.

Water PollutionWater Pollution

Water Pollution is any change to Water Pollution is any change to water that has a harmful effect on water that has a harmful effect on people or other living organisms.people or other living organisms.

Even treated sewage can pollute.Even treated sewage can pollute. Fertilizers and Pesticides can pollute Fertilizers and Pesticides can pollute

nearby waters such as rivers.nearby waters such as rivers.

Sewage SystemSewage System

ReviewReview

Why isn’t most of the water on Earth’s Why isn’t most of the water on Earth’s surface available for people to use?surface available for people to use?

Most water on Earth is salty, and Most water on Earth is salty, and much of the fresh water is ice.much of the fresh water is ice.

Name four types of human activities Name four types of human activities that can be sources of water pollution.that can be sources of water pollution.

Agriculture, industry, construction, Agriculture, industry, construction, mining.mining.

ReviewReview

Why can finding the source of water pollution be Why can finding the source of water pollution be difficult?difficult?

The source can be far from the pollution. Pollutants The source can be far from the pollution. Pollutants can dissolve and move throughout a body of water. can dissolve and move throughout a body of water. Sources can be hidden underground.Sources can be hidden underground.

What is sewage? Why should it be treated before What is sewage? Why should it be treated before being released into the environment?being released into the environment?

Sewage is the water and human wastes that are Sewage is the water and human wastes that are washed down sinks and toilets. It contains disease washed down sinks and toilets. It contains disease causing organisms that can mix with water used for causing organisms that can mix with water used for drinking or swimming, and make people ill.drinking or swimming, and make people ill.