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Hydrosphere

Hydrosphere. Environmental Studies IDC3O3 Ms. Nguyen. More than two thirds of the world ’ s households must fetch water from outside the home When water is scarce and difficult to obtain, it discourages proper sanitation Availability doesn ’ t always mean affordability

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Hydrosphere

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  1. Hydrosphere Environmental Studies IDC3O3 Ms. Nguyen

  2. More than two thirds of the world’s households must fetch water from outside the home • When water is scarce and difficult to obtain, it discourages proper sanitation • Availability doesn’t always mean affordability • Water sellers offer delivery to homes in most countries, but the quality often is questionable • Price may be more than most families can afford Lack Access to Clean Water

  3. A typical family in in Lima, Peru uses one-sixth as much water as a middle class American household but pays three times as much for it • If government recommendations were followed to boil the water to prevent diseases, up to one-third of poor family’s income could be used in acquiring and purifying water For example:

  4. Water pollution is anything that degrades water quality • Two types of pollution: • Point source: discharge pollution from specific location such as drain pipes, ditches or sewer outfalls • Example: factories, power plants, sewage treatment plants, underground coal mines and oil wells • Nonpoint source: water pollution are scattered or diffuse, having no specific locations where they discharge into a particular body of water • Run-off from farm fields and feedlots, golf courses, lawns and gardens, construction sites, logging areas, roads, streets and parking lots • Difficult to monitor, regulate and treat than point sources Water Pollution

  5. a major nonpoint pollution is atmospheric deposition of contaminates carried by air currents and precipitated into watersheds or directly onto surface water as snow, rain or dry particles. • For example: • The Great Lakes have been found to be accumulating industrial chemicals such as PCBs, dioxins, and agricultural toxins such as insecticide toxaphene • 26,000 metric tons of PCBs over the past 12 years have “disappeared” from Lake Superior and carried by air currents to other areas Continue…

  6. Point and nonpoint sources of pollution

  7. Amount of oxygen dissolved in water is a good indicator of water quality • Oxygen with a water content above 6 parts per million (ppm) will support many forms of aquatic life • Less than 2ppm, oxygen will only support worms, bacteria, fungi and other detritus feeders and decomposers • We use aquatic microorganisms as bioindicators • Caddisflies and dragonfly larvae = good water quality; worms = poor What is a good indicator of water quality?

  8. Oxygen is added to water by diffusion from the air, especially when turbulence and mixing rates are high • By photosynthesis of green plants, algae and cyanobacteria (blue –green bacteria) • Oxygen is removed from water by respiration and chemical processes that consume oxygen How is oxygen cycled in water?

  9. Eutrophication = process by which a body of water acquires a high concentration of nutrients, especially phosphates and nitrates or organic wastes • E.g. Organic waste such as sewage, paper pulp or food waste are rich in nutrients • Impact = Increases plant and algae growth The Impact of Eutrofication

  10. With increased growth comes increased rate of death and decay  results in the growth of oxygen demanding decomposing bacteria • Biochemical oxygen demand (BOD) = measure of the oxygen used by microorganisms to decompose organic matter • High levels of BOD mean low levels of dissolved oxygen in the water • Since low levels of DO is available in the water, fish & other aquatic organisms may not survive • The affects of oxygen-demanding wastes on rivers depends to a great extent on the volume, flow and temperature of the river water The Impact of Eutrofication

  11. Oxygen decline downstream is called the oxygen sag Continue…

  12. http://www.scivee.tv/node/14602 Continue…

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