Water Pollution

  • View

  • Download

Embed Size (px)

Text of Water Pollution

  • 1.Presented by Dr. B. Victor Water Pollution

2. About the presenter

  • Dr.B.Victor is a highly experienced postgraduate biology teacher, recently retired from the reputed educational institution St. Xavier s College, Palayamkottai, India-627001.
  • He wasthe dean of sciences and assistant controller of examinations.
  • He has more than 32 years of teaching and research experience
  • He hastaught a diversity of courses ranging from pre-university to post graduate classes.
  • Send your comments to : bonfiliusvictor@gmail.com

3. Water is essential to life on earth. 4. Importance of water

  • Organisms are composed of much water70%-95%
  • Supportive external environment for aquatic organisms
  • Cellular medium within which biochemical reactions can occur
  • Transport medium for food, oxygen, and other things needed by cells
  • Means of support- Turgid plant cells /Hydrostatic animal support systems

5. Three forms of Water.

  • Solids:When water becomes very cold and freezes it will change from a liquid to a solid.It has a definite form and shape.
  • Liquids: When water takes the shapeof its container it is in a liquid form.
  • Gases:When water is seen in a vapor form and has no definite size or shape it is in a gas form.

6. Distribution of global water 7. The earth's water supply

  • 97.2% of the Earth's water supply is salt water.
  • Only 2.8% is fresh water!

8. Salt and freshwater relationship 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. Earth as water planet

  • Earth is often referred to as`the water planet'.
  • 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.
  • Without water, life could not exist.

11. Theearth'sfreshwater supply

  • Only about3%of Earth's water is fresh.
  • Two percentof the Earth's water (about 66% of all fresh water) is in solid form, found in ice caps and glaciers.
  • One percent of all the Earth's water in a form useable to humans and land animals.
  • 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.)

12. Distribution of water

  • Ocean Water :The vast majority of water on the planet is the salt water in the oceans and seas.
  • Fresh Surface Water :This is the fresh water in rivers, streams, lakes, ponds and similar bodies of water.
  • 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!

13. Water : A precious Natural Resource

  • We use water for drinking, irrigation, industrial purposes and energy production.Water use
  • agriculture and energy production - 80%
  • industry and public use - 20%

14. Water is used in many ways

  • as a nourisher of plant and animal life,
  • a bearer of food,
  • a prime element of industrial processes, and
  • a medium for transportation

15. Significance of water

  • Water is an integral part of life on this planet.
  • It is an odorless, tasteless, substance that covers more than three-fourths of the Earth's surface.
  • Most of the water on Earth, 97% to be exact, is salt water found in the oceans.
  • We can not drink salt water or use it for crops because of the salt content.
  • We can remove salt from ocean water, but the process is very expensive.

16. Hydrologic cycle - water cycle

  • Two main processes: precipitation and evaporation
  • Powered by energy from the sun
  • Hydrologic cycle purifies water

17. Global hydrologic cycle 18. Water Cycle

  • Saltwater evaporates from sun's energy producing fresh water in clouds; leaves salts in ocean.
  • Water vapor cools and condenses to precipitation over oceans and land.
  • Runoff forms fresh water lakes, streams, ponds, groundwater, and is held in plants and transpired.

19. Water consumption/ countries 20. Human activity disrupts local water cycles

  • Irrigation
  • Clear cutting of forests
  • Watershed disturbance
  • Loss of minerals through runoff
  • Desertification

21. Water consumption/use 22. Daily use of water 23. Pollution of water 24. Water Pollution 25. Where do Water pollutants come from?

  • 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 .
  • 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.

26. PollutionofWater

  • 1. Industrial pollution
  • 2. Surface pollution
  • 3. Groundwater contamination
  • 4. Sewage pollution
  • 5.Oil pollution
  • 6.Thermal pollution

27. Sources of Water pollution 28. Water pollutants

  • Industrial Effluents This waste water may contain acids, alkalis, salts, poisons, oils and in some cases harmful bacteria.
  • Mining and Agricultural Wastes Mines, especially gold and coal mines, are responsible for large quantities of acid water.
  • Agricultural pesticides, fertilizers and herbicidesmay wash into rivers and stagnant water bodies.
  • Sewage Disposal and Domestic Wastes Sewage as well as domestic and farm wastes were often allowed to pollute rivers and dams.

29. Water pollution 30. Non-persistent (degradable )Water pollutants

  • Domesticsewage
  • Fertilizers
  • Someindustrial wastes

31. Non-persistent (degradable) water pollutants

  • These compounds can be broken down by chemical reactions or by natural bacteria into simple, non-polluting substances such as carbon dioxide and nitrogen.
  • if the pollution load is high, this process can lead to low oxygen levels and eutrophication.
  • This damage is reversible.

32. Persistent Water pollutants

  • some pesticides (e.g., DDT, dieldrin)
  • some leachate components from landfill sites (municipal, industrial)
  • petroleum and petroleum products
  • PCBs, dioxins, polyaromatic hydrocarbons (PAHs)
  • radioactive materials such as strontium-90, cesium-137, radium-226, and uranium
  • metals such as lead, mercury, cadmium

33. Persistent Water pollutants

  • This is the most rapidly growing type of pollution
  • This includes substances that degrade very slowly or cannot be broken down at all;
  • Theymay remain in the aquatic environment for years or longer periods of time.
  • The damage they cause is either irreversible or repairable only over decades or centuries

34. Otherw ater quality pollutants

  • warm water from cooling towers (thermal pollution)
  • floating debris
  • garbage
  • foam
  • These physical pollutants interfere mainly with the usability and/or aesthetic appeal of the water. In certain cases, thermal pollution can kill fish.

35. 1 . ClassesofWater pollutants

  • Pathogens Bacteria, Viruses, Protozoa, Parasitic Worms, Colliform Bacteria Used As Indicators Of Water Quality
  • Oxygen Demanding Wastes Organics That Are Decomposed By Bacteria And That Use A Lot Of O2, Dissolved Oxygen (DO) Decreases, And BOD Increases
  • Water Soluble Inorganic Chemicals Acids, Salts, Toxic Metal Compounds Like Mercury, And Lead.
  • Inorganic Plant Nutrients Water Soluble Phosphates, Nitrates => Algal Blooms, Decreased Dissolved O2, Increased BOD, Methemoglobinemia (="blue baby syndrome")

36. 2. ClassesofWater pollutants

  • Organic Chemicals Oil, Gas, Plastics, Pesticides, Cleaning Solvents, Detergents, Etc.
  • Sediment & Suspended Mater Insoluble Soil Particulates & Other Solids.Clouds The Water, Decreasing Photosynthesis, Carries Pesticides And Disrupts Aquatic Food Webs.
  • Radioactive Isotopes Are Biologically Amplified To Higher Concentrations In The Food Chain.Ionizing Radiation & Birth Defects, Cancer.
  • Warmed Water From Power Plants, Decreases DO And Increases Susceptibility To Diseases And Parasites And Toxic Wastes.
  • Alien Species Zebra Mussels, Asiatic Catfish, Sea Lamprey, etc.Out compete Native Species And Ultimately Decrease Biodiversity

37. Industrial Water pollution

  • Industries discharge a variety of pollutants in their wastewater including heavy metals , resin pellets, organic toxins, oils, nutrients, and solids.


  • Over 1 bil