Transcript Water Pollution

Water Pollution
G. Tyler Miller’s
Living in the Environment
Chapter 20
Types and Sources of Water Pollution
Point sources
Nonpoint sources
Biological oxygen demand
Water
Quality
Do (ppm) at 20˚C
Good
Water quality
8-9
Slightly
polluted
6.7-8
Moderately
polluted
Heavily
polluted
Gravely
polluted
4.5-6.7
Below 4.5
Below 4
Pg. 535
Point and Nonpoint Sources
NONPOINT SOURCES
Rural homes
Cropland
Urban streets
Animal feedlot
Suburban
development
POINT
SOURCES
Wastewater
treatment
plant
Factory
Water pollution

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
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Bacteria,Viruses,Protozoa, Parasitic worms
Oxygen demanding substances
Inorganic plant nutrients
Organic chemicals
Sediment or suspended matter
Thermal pollution
Genetic pollution
Biological
Magnification
Water
0.000002 ppm
Herring gull
124 ppm
Phytoplankton
0.0025 ppm
Herring gull eggs
124 ppm
Lake trout
4.83 ppm
Zooplankton
0.123 ppm
Rainbow smelt
1.04 ppm
Pollution of Streams
 Oxygen sag curve
Fig. 20-5
Pollution of Lakes
 Eutrophication
Discharge of untreated
municipal sewage
(nitrates and phosphates)
Nitrogen compounds
produced by cars
and factories
Discharge of
detergents
( phosphates)
Discharge of treated
municipal sewage
(primary and secondary
treatment:
nitrates and phosphates)
Natural runoff
(nitrates and
phosphates
Manure runoff
From feedlots
(nitrates and
Phosphates,
ammonia)
Runoff from streets,
lawns, and construction
Lake ecosystem lots (nitrates and
nutrient overload
phosphates)
and breakdown of
chemical cycling
Runoff and erosion
Dissolving of
(from from cultivation,
nitrogen oxides
mining, construction,
(from internal combustion
and poor land use)
engines and furnaces)
Fig .22.7, p. 499
Solutions to better water quality
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Drainage Area Management Plans
Agriculture plots
1987 Water Quality Act
Leaking
tank
Water
table
Groundwater
flow
Free gasoline
dissolves in
Gasoline
groundwater
leakage plume
(dissolved
(liquid phase)
phase)
Migrating
vapor phase
Contaminant plume moves
with the groundwater
Water well
Fig. 20-12
Groundwater Pollution: Causes
Hazardous waste injection well
Pesticides
Coal strip
mine runoff
De-icing
road salt
Pumping
well
Waste lagoon
Gasoline
station
Water pumping
well Landfill
Buried gasoline
and solvent tank
Cesspool
septic tank
Sewer
Leakage from faulty
casing
Accidental
spills
Discharge
Confined aquifer
Groundwater
flow
Fig. 20-11
Groundwater Pollution Prevention
Monitoring aquifers
Strictly regulating hazardous waste
disposal
Storing hazardous materials above
ground
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;
Urban sprawl
Bacteria and viruses
from
sewers and septic
tanks contaminate
shellfish beds
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.
Closed
shellfish beds
Closed
beach
Oxygen-depleted
zone
Red tides
Excess nitrogen causes
explosive growth of
toxicmicroscopic algae,
poisoning fish and
marine mammals.
Toxic sediments
Chemicals and toxic
metals contaminate
shellfish beds, kill
spawning fish, and
accumulate in the tissues
of bottom feeders.
Fig. 20-15
Oxygen-depleted zone
Sedimentation and algae
overgrowth reduce sunlight,
kill beneficial sea grasses, use
up oxygen, and degrade habitat.
Healthy zone
Clear, oxygen-rich
waters promote growth
of plankton and sea grasses,
and support fish.
Fig. 21-10, p. 505
Reducing Water Pollution through
Sewage Treatment

Primary and Secondary sewage treatment.
Figure 20-19
Technological Approach: Using
Wetlands to Treat Sewage
(
Sewage
Treated
water
Wetland type
plants
First concrete pool
(
Wetland type
plants
45 centimeter
layer of limestone
gravel coated with
decomposing bacteria
Second concrete pool
Global Outlook: Stream Pollution in
Developing Countries
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Water in many of
central China's rivers
are greenish black from
uncontrolled pollution
by thousands of
factories.
Figure 20-7
Case Study: India’s Ganges River: Religion,
Poverty, and Health
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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.
Case Study: India’s Ganges River: Religion,
Poverty, and Health
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Daily, more than 1
million Hindus in India
bathe, drink from, or
carry out religious
ceremonies in the
highly polluted Ganges
River.
Drinking Water Quality
 Bottled water
 Safe Drinking Water Act
 Maximum contaminant levels
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.
Using Laws to Protect Drinking
Water
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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.
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.
Roger Rosenblatt
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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