Water Pollution


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Water Pollution

  1. 1. Presented by Dr. B. Victor Water Pollution
  2. 2. About the presenter <ul><li>Dr.B.Victor is a highly experienced postgraduate biology teacher, recently retired from the reputed educational institution St. Xavier’ s College, Palayamkottai, India-627001. </li></ul><ul><li>He was the dean of sciences and assistant controller of examinations. </li></ul><ul><li>He has more than 32 years of teaching and research experience </li></ul><ul><li>He has taught a diversity of courses ranging from pre- university to post graduate classes. </li></ul><ul><li>Send your comments to : bonfiliusvictor@gmail.com </li></ul>
  3. 3. Water is essential to life on earth.
  4. 4. Importance of water <ul><li>Organisms are composed of much water––70%-95% </li></ul><ul><li>Supportive external environment for aquatic organisms </li></ul><ul><li>Cellular medium within which biochemical reactions can occur </li></ul><ul><li>Transport medium for food, oxygen, and other things needed by cells </li></ul><ul><li>Means of support- Turgid plant cells /Hydrostatic animal support systems </li></ul>
  5. 5. Three forms of Water. <ul><li>Solids: When water becomes very cold and freezes it will change from a liquid to a solid. It has a definite form and shape. </li></ul><ul><li>Liquids: When water takes the shape of its container it is in a liquid form. </li></ul><ul><li>Gases: When water is seen in a vapor form and has no definite size or shape it is in a gas form. </li></ul>
  6. 6. Distribution of global water
  7. 7. The earth's water supply <ul><li>97.2% of the Earth's water supply is salt water. </li></ul><ul><li>Only 2.8% is fresh water! </li></ul>
  8. 8. Salt and freshwater relationship
  9. 9. World Water Supply 97.200% salt water in the oceans 02.014% ice caps and glaciers 00.600% groundwater 00.009% surface water 00.005% soil moisture 00.001% atmospheric moisture
  10. 10. Earth as water planet <ul><li>Earth is often referred to as `the water planet'. </li></ul><ul><li>Earth is unique amongst planets of our solar system because of its abundant water - in oceans, in the atmosphere, in glaciers and as fresh water on land. </li></ul><ul><li>Without water, life could not exist. </li></ul>
  11. 11. The earth's freshwater supply <ul><li>Only about 3% of Earth's water is fresh. </li></ul><ul><li>Two percent of the Earth's water (about 66% of all fresh water) is in solid form, found in ice caps and glaciers. </li></ul><ul><li>One percent of all the Earth's water in a form useable to humans and land animals. </li></ul><ul><li>This fresh water is found in lakes, rivers, streams, ponds, and in the ground. (A small amount of water is found as vapor in the atmosphere.)  </li></ul>
  12. 12. Distribution of water <ul><li>Ocean Water : The vast majority of water on the planet is the salt water in the oceans and seas. </li></ul><ul><li>Fresh Surface Water : This is the fresh water in rivers, streams, lakes, ponds and similar bodies of water. </li></ul><ul><li>Groundwater : The majority of the planet's liquid freshwater is stored in underground aquifers. Water that enters an aquifer remains there for an average of 1,400 years! </li></ul>
  13. 13. Water : A precious Natural Resource <ul><li>We use water for drinking, irrigation, industrial purposes and energy production. Water use </li></ul><ul><li>agriculture and energy production - 80% </li></ul><ul><li>industry and public use - 20% </li></ul>
  14. 14. Water is used in many ways <ul><li>as a nourisher of plant and animal life, </li></ul><ul><li>a bearer of food, </li></ul><ul><li>a prime element of industrial processes, and </li></ul><ul><li>a medium for transportation </li></ul>
  15. 15. Significance of water <ul><li>Water is an integral part of life on this planet. </li></ul><ul><li>It is an odorless, tasteless, substance that covers more than three-fourths of the Earth's surface. </li></ul><ul><li>Most of the water on Earth, 97% to be exact, is salt water found in the oceans. </li></ul><ul><li>We can not drink salt water or use it for crops because of the salt content. </li></ul><ul><li>We can remove salt from ocean water, but the process is very expensive. </li></ul>
  16. 16. Hydrologic cycle - water cycle   <ul><li>Two main processes: precipitation and evaporation </li></ul><ul><li>Powered by energy from the sun  </li></ul><ul><li>Hydrologic cycle purifies water </li></ul>
  17. 17. Global hydrologic cycle
  18. 18. Water Cycle <ul><li>Saltwater evaporates from sun's energy producing fresh water in clouds; leaves salts in ocean. </li></ul><ul><li>Water vapor cools and condenses to precipitation over oceans and land. </li></ul><ul><li>Runoff forms fresh water lakes, streams, ponds, groundwater, and is held in plants and transpired. </li></ul>
  19. 19. Water consumption/ countries
  20. 20. Human activity disrupts local water cycles <ul><li>Irrigation </li></ul><ul><li>Clear cutting of forests </li></ul><ul><li>Watershed disturbance </li></ul><ul><li>Loss of minerals through runoff </li></ul><ul><li>Desertification </li></ul>
  21. 21. Water consumption/use
  22. 22. Daily use of water
  23. 23. Pollution of water
  24. 24. Water Pollution
  25. 25. Where do Water pollutants come from? <ul><li>Point Sources – A single definable source of the pollution, e.g. a factory, a sewage plant, etc. Point-source pollution is usually monitored and regulated . </li></ul><ul><li>Non-point sources – No one single source, but a wide range of sources, e.g. runoff from urban areas, or farmland. Non-point sources are much more difficult to monitor and control. </li></ul>
  26. 26. Pollution of Water <ul><li>1. Industrial pollution </li></ul><ul><li>2. Surface pollution </li></ul><ul><li>3. Groundwater contamination </li></ul><ul><li>4. Sewage pollution </li></ul><ul><li>5.Oil pollution </li></ul><ul><li>6.Thermal pollution </li></ul>
  27. 27. Sources of Water pollution
  28. 28. Water pollutants <ul><li>Industrial Effluents This waste water may contain acids, alkalis, salts, poisons, oils and in some cases harmful bacteria. </li></ul><ul><li>Mining and Agricultural Wastes Mines, especially gold and coal mines, are responsible for large quantities of acid water. </li></ul><ul><li>Agricultural pesticides, fertilizers and herbicides may wash into rivers and stagnant water bodies. </li></ul><ul><li>Sewage Disposal and Domestic Wastes Sewage as well as domestic and farm wastes were often allowed to pollute rivers and dams. </li></ul>
  29. 29. Water pollution
  30. 30. Non-persistent (degradable ) Water pollutants <ul><li>Domestic sewage </li></ul><ul><li>Fertilizers </li></ul><ul><li>Some industrial wastes </li></ul>
  31. 31. Non-persistent (degradable) water pollutants <ul><li>These compounds can be broken down by chemical reactions or by natural bacteria into simple, non-polluting substances such as carbon dioxide and nitrogen. </li></ul><ul><li>if the pollution load is high, this process can lead to low oxygen levels and eutrophication. </li></ul><ul><li>This damage is reversible. </li></ul>
  32. 32. Persistent Water pollutants <ul><li>some pesticides (e.g., DDT, dieldrin) </li></ul><ul><li>some leachate components from landfill sites (municipal, industrial) </li></ul><ul><li>petroleum and petroleum products </li></ul><ul><li>PCBs, dioxins, polyaromatic hydrocarbons (PAHs) </li></ul><ul><li>radioactive materials such as strontium-90, cesium-137, radium-226, and uranium </li></ul><ul><li>metals such as lead, mercury, cadmium </li></ul>
  33. 33. Persistent Water pollutants <ul><li>This is the most rapidly growing type of pollution </li></ul><ul><li>This includes substances that degrade very slowly or cannot be broken down at all; </li></ul><ul><li>They may remain in the aquatic environment for years or longer periods of time. </li></ul><ul><li>The damage they cause is either irreversible or repairable only over decades or centuries </li></ul>
  34. 34. Other w ater quality pollutants <ul><li>warm water from cooling towers (thermal pollution) </li></ul><ul><li>floating debris </li></ul><ul><li>garbage </li></ul><ul><li>foam </li></ul><ul><li>These physical pollutants interfere mainly with the usability and/or aesthetic appeal of the water. In certain cases, thermal pollution can kill fish. </li></ul>
  35. 35. 1 . Classes of Water pollutants <ul><li>  Pathogens  Bacteria, Viruses, Protozoa, Parasitic Worms, Colliform Bacteria Used As Indicators Of Water Quality </li></ul><ul><li>Oxygen Demanding Wastes  Organics That Are Decomposed By Bacteria And That Use A Lot Of O2, Dissolved Oxygen (DO) Decreases, And BOD Increases </li></ul><ul><li>Water Soluble Inorganic Chemicals  Acids, Salts, Toxic Metal Compounds Like Mercury, And Lead. </li></ul><ul><li>Inorganic Plant Nutrients  Water Soluble Phosphates, Nitrates => Algal Blooms, Decreased Dissolved O2, Increased BOD, Methemoglobinemia (=&quot;blue baby syndrome&quot;) </li></ul>
  36. 36. 2. Classes of Water pollutants <ul><li>Organic Chemicals  Oil, Gas, Plastics, Pesticides, Cleaning Solvents, Detergents, Etc.   </li></ul><ul><li>Sediment & Suspended Mater  Insoluble Soil Particulates & Other Solids. Clouds The Water, Decreasing Photosynthesis, Carries Pesticides And Disrupts Aquatic Food Webs.   </li></ul><ul><li>Radioactive Isotopes  Are Biologically Amplified To Higher Concentrations In The Food Chain. Ionizing Radiation & Birth Defects, Cancer. </li></ul><ul><li>  </li></ul><ul><li>Warmed Water  From Power Plants, Decreases DO And Increases Susceptibility To Diseases And Parasites And Toxic Wastes.   </li></ul><ul><li>Alien Species  Zebra Mussels, Asiatic Catfish, Sea Lamprey, etc. Out compete Native Species And Ultimately Decrease Biodiversity </li></ul>
  37. 37. Industrial Water pollution <ul><li>Industries discharge a variety of pollutants in their wastewater including heavy metals , resin pellets, organic toxins, oils, nutrients, and solids. </li></ul>
  38. 38. <ul><li>Over 1 billion people lack access to safe water supplies, while 2.6 billion people lack adequate sanitation. This has led to widespread microbial contamination of drinking water. </li></ul><ul><li>Water-associated infectious diseases claim up to 3.2 million lives each year, approximately 6% of all deaths globally. </li></ul>Microbial contamination of water
  39. 39. Eutrophication <ul><li>Increases in nutrient loading may lead to eutrophication . </li></ul><ul><li>Organic wastes such as sewage impose high oxygen demands on the receiving water leading to oxygen depletion. </li></ul>
  40. 40. Drought <ul><li>D rought causes more damage and suffering than any other natural disaster. </li></ul><ul><li>80 countries experience droughts lasting more than 1 year. </li></ul><ul><li>According to the UN, almost 500 million people, in 31 countries (~40% of the world’s population) experience chronic water shortages today. </li></ul>
  41. 41. Flooding: o versupply of water <ul><li>Water Logged Soil </li></ul><ul><li>Nutrient Leakage </li></ul><ul><li>Topsoil Erosion </li></ul>
  42. 42. Acid rain <ul><li>Acid rain is formed when moisture in the clouds mixes with sulfur or nitrogen in the air. </li></ul><ul><li>Acid rain includes rain, sleet or snow with a pH level that falls below 5.6 (normal rainwater). </li></ul><ul><li>The sulfur and nitrogen get into the air by the burning of fossil fuels such as coal and gasoline. The average pH of rainfall is 4.3. </li></ul>
  43. 44. River pollution <ul><li>Asian rivers are the most polluted in the world. </li></ul><ul><li>Three times as many bacteria from human waste as the global average </li></ul><ul><li>20 times more lead than rivers in industrialized countries. </li></ul>
  44. 45. Mass fish kills
  45. 46. Plastic waste in water <ul><li>Each year, plastic waste in water and coastal areas kills up to: </li></ul><ul><li>100,000 marine mammals, </li></ul><ul><li>1 million sea birds, and </li></ul><ul><li>countless fish. </li></ul>
  46. 47. Water borne diseases <ul><li>Diseases caused by the ingestion of water contaminated with pathogenic bacteria, viruses, or parasites include: </li></ul><ul><li>cholera </li></ul><ul><li>typhoid </li></ul><ul><li>schistosomiasis </li></ul><ul><li>dysentery and other diarrheal diseases </li></ul>
  47. 48. Disease burden from water pollution <ul><li>Water-associated infectious diseases claim up to 3.2 million lives each year, approximately 6% of all deaths globally. </li></ul><ul><li>The burden of disease from inadequate water, sanitation, and hygiene totals 1.8 million deaths and the loss of greater than 75 million healthy life years. </li></ul>
  48. 49. Water and sanitation <ul><li>It is well established that investments in safe drinking water and improved sanitation show a close correspondence with improvement in human health and economic productivity. </li></ul><ul><li>Each person needs 20 to 50 liters of water free of harmful chemical and microbial contaminants each day for drinking and hygiene. </li></ul><ul><li>There remain substantial challenges to providing this basic service to large segments of the human population. </li></ul>
  49. 50. Oil Pollution of water <ul><li>Both Point and Nonpoint Sources </li></ul><ul><li>Largest source of oil pollution is pipeline leaks and runoff </li></ul><ul><ul><li>61% ocean oil pollution river & urban runoff </li></ul></ul><ul><ul><li>30% intentional discharges from tankers </li></ul></ul><ul><ul><li>5% accidental spills from tankers </li></ul></ul>
  50. 51. Remedial measures <ul><li>Locate the point sources of pollution. </li></ul><ul><li>Work against acid rain. </li></ul><ul><li>Educate your community. </li></ul><ul><li>Ensure sustainable sewage treatment. </li></ul><ul><li>Watch out for toxins. </li></ul><ul><li>Be careful what you throw away. </li></ul><ul><li>Use water efficiently. </li></ul><ul><li>Prevent pollution . </li></ul><ul><li>Think globally, act locally. </li></ul>
  51. 52. Thank you