Env Ch15b

  1. The Aral Sea
    • •Once the fourth-largest lake on Earth
    • -It has lost more than 80% of its volume in just 45 years
    • The two rivers leading into the Aral Sea were diverted to irrigate cotton fields
    • •Consequences of a shrinking sea
    • 60,000 fishing jobs are gone
    • Pesticide-laden dust from the lake bed is blown into the air
    • The cotton cannot bring back the region’s economy
  2. Desalinization
    the removal of salt from seawater or other water of marginal quality
  3. Distilling
    hastens evaporation and condenses the vapor
  4. Reverse Osmosis
    forces water through membranes to filter out salts
  5. Xeriscaping
    landscaping using plants adapted to arid conditions
  6. Half of the world’s major rivers are seriously depleted and polluted
    • Water for human consumption and other organisms needs to be…
    • Disease-free
    • Nontoxic
  7. Pollution
    the release of matter or energy into the environment that causes undesirable impacts on the health and well-being of humans or other organisms
  8. Solution to water polution
    • Phosphate-free detergents
    • Planting vegetation to increase nutrient uptake
    • Treat wastewater
    • Reduce fertilizer application
  9. Pathogens and waterbourne diseases
    • Enters water supply via inadequately treatedhuman waste and animal waste via feedlot
    • Causes more human health problems than any other type of water pollution
    • Fecal coliform bacteria indicate fecal contamination of water
    • -The water can hold other pathogens, such as giardiais, typhoid, hepatitis A
  10. Pathogens in Waters
    • Currently, 1.1 billion people are without safe drinking water
    • 2.4 billion have no sewer or sanitary facilities
    • Mostly rural Asians and Africans
    • An estimated 5 million people die per year
  11. Sediment Pollution
    • -Clear-cutting, mining, poor cultivation practices
    • -Dramatically changes aquatic habitats, and fish may not survive
    • -Solutions: better management of farms and forests; avoid large-scale disturbance of vegetation
  12. Thermal Pollution
    • •Warmer water holds less oxygen
    • -Dissolved oxygen decreases as temperature increases
    • -Industrial cooling heats water
    • -Removing streamside cover also raises water temperature
    • •Water that is too cold causes problems
    • -Water at the bottom of reservoirs is colder
    • -When water is released, downstream water temperatures drop suddenly and may kill aquatic organisms
  13. Point Source Water Pollution
    • •discrete locations of pollution
    • -Factory or sewer pipes
  14. Nonpoint Source Water Pollution
    • •pollution from multiple cumulative inputs over a large area
    • -Farms, cities, streets, neighborhoods
    • •The U.S. Clean Water Act
    • -Addressed point sources
    • -Targeted industrial discharge
    • In the U.S., nonpoint sources have a greater impact on quality
    • -Limit development on watershed land surrounding reservoirs
  15. Primary Treatment
    the physical removal of contaminants in settling tanks (clarifiers)
  16. Secondary Treatment
    water is stirred and aerated so aerobic bacteria degrade organic pollutants
Card Set
Env Ch15b