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

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

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

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

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

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

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

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

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

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

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

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

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