Ppt on water pollution


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Water Pollution

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Ppt on water pollution

  1. 1. Presentation on WATER POLLUTION Dr. Vivek Kumar
  2. 2. Water makes us unique and gives life to Earth.
  3. 3. What is water pollution? Any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired usage.
  4. 4. What is water pollution? WHO: • 3.4 million premature deaths each year from waterborne diseases • 1.9 million from diarrhea • U.S. 1.5 million illnesses • 1993 Milwaukee 370,000 sick
  5. 5. What is water pollution? Need to study Table 22-1 Page 492 Infectious Agents: bacteria and viruses often from animal wastes Oxygen Demanding Wastes: organic waste that needs oxygen often from animal waste, paper mills and food processing. Inorganic Chemicals: Acids and toxic chemicals often from runoff, industries and household cleaners
  6. 6. What is water pollution? Organic Chemicals: oil, gasoline, plastics, detergents often from surface runoff, industries and cleaners Plant Nutrients: water soluble nitrates, ammonia and phosphates often from sewage, agriculture and urban fertilizers Sediment: soils and silts from land erosion can disrupt photosynthesis, destroy spawning grounds, clog rivers and streams Heat Pollution and Radioactivity: mostly from powerplants
  7. 7. How do we measure water quality Bacterial Counts: Fecal coliform counts from intestines of animals • None per 100 ml for drinking • >200 per 100 ml for swimming Sources: human sewage, animals, birds, raccoons, etc. See table 22-2 on page 493 for diseases transmitted by contaminated drinking water.
  8. 8. How do we measure water quality Dissolved Oxygen: BOD Biological Oxygen Demand…the amount of oxygen consumed by aquatic decomposers Chemical Analysis: looking for presence of inorganic or organic chemicals Suspended Sediment water clarity
  9. 9. How do we measure water quality Indicator Species: organisms that give an idea of the health of the water body. • Mussels, oysters and clams filter water
  10. 10. Types, Effects and Sources of Water Pollution  Point sources  Nonpoint sources  Water quality Fig. 22-3 p. 494
  11. 11. Point and Nonpoint Sources NONPOINT SOURCES Urban streets Suburban development Wastewater treatment plant Rural homes Cropland Factory Animal feedlot POINT SOURCES Fig. 22-4 p. 494
  12. 12. Major Sources of Water Pollution Agriculture: by far the leader • Sediment, fertilizers, bacteria from livestock, food processing, salt from soil irrigation Industrial: factories and powerplants Mining: surface mining toxics, acids, sediment
  13. 13. Freshwater Stream Pollution Flowing streams can recover from moderate level of degradable water pollution if their flows are not reduced. • Natural biodegradation process • Does not work if overloaded or stream flow reduced • Does not work against non biodegradable pollutants
  14. 14. Pollution of Streams  Oxygen sag curve  Factors influencing recovery Fig. 22-5 p. 496 What factors will influence this oxygen sag curve?
  15. 15. Two WorldsDeveloping Countries: Serious and growing problem • Half of world’s 500 major rivers heavily polluted • Sewage treatment minimal $$$ • Law enforcement difficult • 10% of sewage in China treated • Economic growth with little $$$ to clean up
  16. 16. India’s Ganges River • Holy River (1 million take daily holy dip) • 350 million (1/3rd of pop) live in watershed • Little sewage treatment • Used for bathing, drinking etc. • Bodies (cremated or not) thrown in river • Good news is the Indian government is beginning to work on problem
  17. 17. Freshwater Lake Pollution Dilution as a solution in lakes less effective • Little vertical mixing • Little water flow (flushing) Makes them more vulnerable • Toxins settle • Kill bottom life • Atmospheric deposition • Food chain disruptions
  18. 18. Biomagnifications of PCBs in an aquatic food chain from the Great Lakes. See figure 22-6 on page 498
  19. 19. Eutrophication of Lakes Eutrophication: nutrient enrichment of lakes mostly from runoff of plant nutrients (nitrates and phosphates) • During hot dry weather can lead to algae blooms • Decrease of photosynthesis • Dying algae then drops DO levels • Fish kills, bad odor
  20. 20. Pollution of Lakes Eutrophication Fig. 22-7 p. 499
  21. 21. Groundwater Pollution: Causes  Low flow rates  Few bacteria  Cold temperatures Coal strip mine runoff Pumping well Waste lagoon Accidental spills Groundwater flow Confined aquifer Discharge Leakage from faulty casing Hazardous waste injection well Pesticides Gasoline station Buried gasoline and solvent tank Sewer Cesspool septic tank De-icing road salt Water pumping well Landfill  Low oxygen Fig. 22-9 p. 502
  22. 22. Groundwater Pollution Prevention  Monitor aquifers  Leak detection systems  Strictly regulating hazardous waste disposal  Store hazardous materials above ground  Find less hazardous substitutes
  23. 23. Ocean Pollution Oceans can disperse and break down large quantities of degradable pollution if they are not overloaded. • Pollution worst near heavily populated coastal zones • Wetlands, estuaries, coral reefs, mangrove swamps • 40% of world’s pop. Live within 62 miles of coast
  24. 24. Ocean Pollution Fig. 22-11 p. 504
  25. 25. Thank you