1. Chapter 4 Land, Water and Air Resources Section 3 Water Pollution and Solutions Notes 4-3

2. Limited Supply  Most water on Earth is salty  97%  Only 3% of all water is usable (fresh)  2/3 of all fresh water is in the form of ice  Groundwater is another form of fresh water  Water stored in layers of soil and rock under the surface of the earth

3. Renewing Supply  Fresh water is renewable  Water cycle continuously renews fresh water  When water evaporates, it leaves the pollution behind  Water is fresh once it is in the form of water vapor  However, water can re-pollute itself if it falls through pollution  Forms acid rain

4. Water Shortages  Occur when people use water fast than it can be renewed  Happens often in a drought  Can also make fresh water, for places that do not have enough rain fall to produce the water that they need, by taking salt out of sea water

5. Water Pollution  Any change in water that has a harmful effect on people or other living things  Iron or copper: make drink and bathing unpleasant  Mercury or benzene: cause sickness or death  Most pollution is caused by human activities  Sewage: water and human waste washed down sinks, toilets and showers  Can make people very ill

6. Water Pollution  Agricultural Waste:  Animals waste and farm chemicals  Fertilizers: chemicals that provide nutrients to help crops grow better  Pesticides: chemicals that kill crop-destroying organisms  These can build up to harmful concentrations

7. Water Pollution  Industry and Mining:  Chemical plants, paper and textile mills, and factories use metal that can pollute.  Metal can harm ecosystems: people, animals, plants and environment  Sediments:  Tiny particles of rock, silt and sand  Can be washed into areas where it covers food, nesting sites and eggs of organisms

8. Water Pollution  Oil and Gasoline:  Oil spills kill fish, birds and other life in ocean areas  Gasoline can leak out of underground tanks and get into groundwater and drinking water  Heat:  Power plants sometimes put hot water used to cool devices back into the environment too soon  Causes plants and animals to die  Cooling towers are now used to keep this from happening

9. Cleaning Up the Water  To reduce water pollution: 1.Treat wastes so they are less harmful 2.Find substitutes for pollutants  Sewage Treatment  Primary Treatment: removes solid materials from wastewater  Water passes through filters  Solids are held in tanks and particles settle out

10. Cleaning Up the Water  Secondary Treatment: bacteria break down solid wastes  Water is treated with chlorine to kill disease causing organisms  Arcata, CA  Wastewater flows into ponds with algae  Algae breaks down sewage  Water moves to marshes with cattails and bulrushes to clean the water  Areas are also for habitats for fish and birds  Also areas for bike riding and trails for recreation

11. Cleaning Up the Water  Oil and Gasoline  Oil spills can be cleaned up with bacteria  Bacteria eat the oil and reproduce as long as there is food  They die off as soon as their food disappears  Big oil spills affect the wildlife before the bacteria can restore the ecosystem  Gasoline spills are hard to clean up  Soil can be removed  However, if gasoline reaches the groundwater…much worse!  Water has to be pumped out and cleaned  Then it can be put back into the ground

12. Cleaning Up the Water  Industrial Chemicals  Industries can recycle their wastes  They save money and reduce pollution  Industries can change how they produce their product  Use less water or create less harmful wastes  Farming Chemicals  Finding alternatives to pesticides and fertilizers  DDT (dichloro-diphenyl-trichloroethane)  1972 DDT usage was stopped  Today it is labeled as a probable human carcinogen  Stays in an organism for a long time

13. What can you do?  Little changes can make a big difference  Don’t pour harsh chemicals down the drain  Don’t dump them in the grass  Paint thinner  Motor oil  Garden chemicals  Use environmentally friendly cleaning supplies