Water Pollution

1
Water Pollution
G. Tyler Millers Living in the
Environment Chapter 20
2
Types and Sources of Water Pollution

• Point sources

• Nonpoint sources

• Biological oxygen demand

• Water quality

Pg. 535
3
Point and Nonpoint Sources
4
Water pollution

• Bacteria,Viruses,Protozoa, Parasitic worms
• Oxygen demanding substances
• Inorganic plant nutrients
• Organic chemicals
• Sediment or suspended matter
• Thermal pollution
• Genetic pollution

5
Biological Magnification
6
Pollution of Streams

• Oxygen sag curve

Fig. 20-5
7
Pollution of Lakes

• Eutrophication

Fig .22.7, p. 499
8
Solutions to better water quality

• Drainage Area Management Plans
• Agriculture plots
• 1987 Water Quality Act

9

Leaking tank
Aquifer
Bedrock
Water table
Groundwater flow
Free gasoline dissolves in groundwater (dissolved
phase)
Gasoline leakage plume (liquid phase)
Migrating vapor phase
Water well
Contaminant plume moves with the groundwater
Fig. 20-12
10
Groundwater Pollution Causes

Hazardous waste injection well
Pesticides
Coal strip mine runoff
De-icing road salt
Buried gasoline and solvent tank
Cesspool septic tank
Pumping well
Gasoline station
Waste lagoon
Water pumping well
Sewer
Landfill
Leakage from faulty casing
Accidental spills
Discharge
Unconfined freshwater aquifer
Confined aquifer
Confined freshwater aquifer
Groundwater flow
Fig. 20-11
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Groundwater Pollution Prevention

• Monitoring aquifers

• Strictly regulating hazardous waste disposal

• Storing hazardous materials above ground

12

Urban sprawl Bacteria and viruses from sewers and
septic tanks contaminate shellfish beds
Cities Toxic metals and oil from streets and
parking lots pollute waters
Industry Nitrogen oxides from autos
and smokestacks, toxic chemicals, and heavy
metals in effluents flow into bays and estuaries.
Construction sites Sediments are washed
into waterways, choking fish and plants, clouding
waters, and blocking sunlight.
Farms Runoff of pesticides, manure, and
fertilizers adds toxins and excess nitrogen and
phosphorus.
Red tides Excess nitrogen causes explosive growth
of toxicmicroscopic 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. 20-15
Fig. 21-10, p. 505
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Reducing Water Pollution through Sewage Treatment

• Primary and Secondary sewage treatment.

Figure 20-19
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Technological Approach Using Wetlands to Treat
Sewage
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Global Outlook Stream Pollution in Developing
Countries

• Water in many of central China's rivers are
  greenish black from uncontrolled pollution by
  thousands of factories.

Figure 20-7
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Case Study Indias Ganges River Religion,
Poverty, and Health

• Religious beliefs, cultural traditions, poverty,
  and a large population interact to cause severe
  pollution of the Ganges River in India.
• Very little of the sewage is treated.
• Hindu believe in cremating the dead to free the
  soul and throwing the ashes in the holy Ganges.
• Some are too poor to afford the wood to fully
  cremate.
• Decomposing bodies promote disease and depletes
  DO.

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Case Study Indias Ganges River Religion,
Poverty, and Health

• Daily, more than 1 million Hindus in India bathe,
  drink from, or carry out religious ceremonies in
  the highly polluted Ganges River.

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Drinking Water Quality

• Bottled water

• Safe Drinking Water Act

• Maximum contaminant levels

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Is Bottled Water the Answer?

• Some bottled water is not as pure as tap water
  and costs much more.
• 1.4 million metric tons of plastic bottles are
  thrown away.
• Fossil fuels are used to make plastic bottles.
• The oil used to produce plastic bottles in the
  U.S. each year would fuel 100,000 cars.

20
Using Laws to Protect Drinking Water

• The U.N. estimates that 5.6 million Americans
  drink water that does not meet EPA standards.
• 1 in 5 Americans drinks water from a treatment
  plant that violated one or more safety standard.

21

What Can You Do?
Water Pollution
Fertilize garden and yard plants with manure
or compost instead of commercial inorganic
fertilizer.
Minimize your use of pesticides.
Do not apply fertilizer or pesticides near a
body of water.
Grow or buy organic foods.
Do not drink bottled water unless tests show
that your tap water is contaminated. Merely
refill and reuse plastic bottles with tap water.
Compost your food wastes.
Do not use water fresheners in toilets.
Do not flush unwanted medicines down the
toilet.
Do not pour pesticides, paints, solvents, oil,
antifreeze, or other products containing harmful
chemicals down the drain or onto the ground.
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Roger Rosenblatt

• It is a hard truth to swallow, but nature does
  not care if we live or die. We cannot survive
  without the oceans, for example, but they can do
  just fine without us.
• End chapter 20