2 Water PollutionWater pollution is the introduction of chemical, physical, or biological agents into water that degrade water quality and adversely affect the organisms that depend on the water.The two main underlying causes of water pollution are industrialization and rapid human population growth.
3 Water PollutionDespite progress in cleaning up many polluted water supplies, some water is still dangerously polluted in the US and other countries.In developing countries the major cause of pollution is not industry, but often the only water available for drinking is polluted with sewage and agricultural runoff.To prevent water pollution, people must understand where pollutants come fromWater pollutions comes from two types of sources: point and nonpoint sources.
4 Point-Source Pollution Pollution discharged from a single source:A FactoryLeaking septic-tank systemsUnlined landfillsLeaking underground storage tanks that contain chemicals or fuelsPolluted water from abandoned and active minesPublic and Industrial wastewater treatment plants
6 Nonpoint-Source Pollution Comes from many different sources that are often difficult to identify:Chemicals added to road surfaces (salt & other de-icing agents)Water runoff from city and suburban streets that may contain oil, gasoline, animal feces, and trash)Pesticides, herbicides, and fertilizer from residential lawns, golf courses, and farmlandPrecipitation containing air pollutants
8 Point vs. Nonpoint Sources of pollution: Which one is harder to regulate and control? Nonpoint pollutants are extremely difficult to regulate and control because they come from many different sources and are difficult to traceThe accumulation of small amounts of pollution from many sources is a major pollution problem– 96% of the polluted bodies of water in the US were contaminated by nonpoint sources.
9 More Than Just Bad Drinking Water Biomagnification is the accumulation of pollutants at successive levels of the food chainPrimary consumers take in small amounts of pollutionSecondary consumers feed on numerous primary consumers, thus accumulating all of the pollutants from each primary consumerBiomagnification has alarming consequences for organisms at the top of the food chainWhat organism is at the top of most food chains?HUMANS
10 BiomagnificationSoil tainted with pesticides washes into a river system where it enters the bodies of zooplankton
12 BiomagnificationSoil tainted with pesticides washes into a river system where it enters the bodies of zooplanktonA hundred of these small organisms are eaten by one small fish
13 DDT in zooplankton: 0.04 ppm DDT in small fish: 0.5 ppm
14 BiomagnificationSoil tainted with pesticides washes into a river system where it enters the bodies of zooplanktonA hundred of these small organisms are eaten by one small fishA hundred of these small fish are eaten by one large fish
15 DDT in zooplankton: 0.04 ppm DDT in small fish: 0.5 ppmDDT in large fish: 2 ppm
16 BiomagnificationSoil tainted with pesticides washes into a river system where it enters the bodies of zooplanktonA hundred of these small organisms are eaten by one small fishA hundred of these small fish are eaten by one large fishA predatory bird eats 10 large fish
17 DDT in zooplankton: 0.04 ppm DDT in small fish: 0.5 ppmEach organism stores the pesticide in its tissues, so at each step along the food chain, the amount of the pesticide passed on to the next organism increases.DDT in eagle: 25 ppmDDT in large fish: 2 ppm
18 Preventing PollutionControlling pollution greatly depends on public awareness of the effects of activities such as spraying lawn chemicals and improper disposal of household wastesMany Federal Laws are designed to improve water qualityClean Water Act of 1972Oil Pollution Act of 1990
19 With freshwater pollution and shortages, why don’t we just turn seawater into safe drinking water?
20 DesalinationDesalination is the process of removing salt from salt water.Seawater desalination facilities are already vital in many arid areas of the world, but many of these desalination plants have been overly expensive, poorly designed, or inaccurately promoted.
21 Advantages of Desalination Supply of water is very reliablePotential to produce high-quality waterMay provide a solution to current and future political and economic conflicts concerning control of available water
22 Disadvantages of Desalination Desalination is substantially more expensive than most other water supply and demand management options, and future costs may actually increase rather than decrease.It is an energy-intensive process, and is more sensitive to changes in energy prices than other sources of water.Desalination has significant environmental impacts just like any other major industrial process.
23 What Now?The potential benefits of ocean desalination are great for human needs, but the economic, cultural, and environmental costs of worldwide commercialization remain high.The best thing you can do, as an individual, is to conserve water in your everyday life.
24 What can you do to conserve water? Take shorter showers and avoid taking baths unless you keep the water level lowInstall a low-flow shower headInstall a low flow toilet, or simply place a water-filled bottle inside your toilet tank to reduce the water used for each flush.Do not let the water run while you brush your teeth.Fill up the sink instead of letting it run while shaving, or washing dishes, etc.Wash only full loads in your dishwasher and washing machine.Water your lawn sparingly