Water Pollution

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Water Pollution
Thanks to Miller and Clements
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Key Concepts

• Types, sources, and effects of water pollutants

• Major pollution problems of surface water

• Major pollution problems of groundwater

• Reduction and prevention of water pollution

• Drinking water quality

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Types and Sources of Water Pollution

• Point sources

• Nonpoint sources

• Biological oxygen demand

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Pollution of Streams

• Oxygen sag curve

• Factors influencing recovery

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Pollution of Lakes

• Eutrophication

• Slow turnover

• Thermal stratification

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Case Study The Great Lakes
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Groundwater Pollution Sources

• Low flow rates

• Cold temperatures

• Fewbacteria

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Groundwater Pollution Prevention

• Monitoring aquifers

• Leak detection systems

• Strictly regulating hazardous waste disposal

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Ocean Pollution
Industry Nitrogen oxides from autos and
smokestacks toxic chemicals, and heavy metals in
effluents flow into bays and estuaries.
Cities Toxic metals and oil from streets
and parking lots pollute waters sewage adds
nitrogen and phosphorus.
Urban sprawl Bacteria and viruses from sewers and
septic tanks contaminate shellfish beds and
close beaches runoff of fertilization from lawns
adds nitrogen and phosphorus.
Construction sites Sediments are washed into
waterways, choking fish and plants,
clouding waters, and blocking sunlight.
Farms Run off of pesticides, manure,
and fertilizers adds toxins and excess nitrogen
and phosphorus.
Red tides Excess nitrogen causes explosive growth
of toxic microscopic algae, poisoning fish and
marine mammals.
Closed shellfish beds
Closed beach
Oxygen-depleted zone
Toxic sediments Chemicals and toxic
metals contaminate shellfish beds, kill spawning
fish, and accumulate in the tissues of bottom
feeders.
Healthy zone Clear, oxygen-rich waters promote
growth of plankton and sea grasses, and support
fish.
Oxygen-depleted zone Sedimentation and
algae overgrowth reduce sunlight, kill beneficial
sea grasses, use up oxygen, and degrade habitat.
Fig. 19.11, p. 489
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Oil Spills

• Sources offshore wells, tankers, pipelines and
  storage tanks

• Effects death of organisms, loss of animal
  insulation and buoyancy, smothering

• Significant economic impacts

• Mechanical cleanup methods skimmers and blotters

• Chemical cleanup methods coagulants and
  dispersing agents

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Solutions Preventing and Reducing Surface Water
Pollution
Nonpoint Sources
Point Sources

• Reduce runoff

• Clean Water Act

• Buffer zone vegetation

• Water Quality Act

• Reduce soil erosion

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Technological Approach Septic Systems

• Require suitable soils and maintenance

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Technological Approach Sewage Treatment

• Mechanical and biological treatment

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Technological Approach Advanced Sewage Treatment

• Removes specific pollutants

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Technological Approach Using Wetlands to Treat
Sewage
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