ENVIRONMENTAL SCIENCE

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ENVIRONMENTAL SCIENCE
13e
CHAPTER 11Water Resources and Water Pollution
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Water video questions

• How much fresh water on earth?
• How much in rivers, lakes, and streams?
• How much is used for growing food?
• How much water needed to produced a pound of
  beef?
• A cup of coffee?
• In US how much water is used for flushing toilet?
• How much water does the average American use per
  day?
• How many people today lack access to clean, safe
  water supply?

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• http//www.youtube.com/watch?vFvkzjt3b-dU
• http//www.youtube.com/watch?v2pXuAw1bSQo

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Core Case Study The Colorado River Story

• 1400 miles through 7 states
• 14 dams and reservoirs
• Electricity for 30 million people
• Water for 15 of U.S. crops and livestock
• Water for desert cities
• Very little water reaches the Gulf of California

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5 major problems

• Colorado river basin includes some of driest
  lands in US and Mexico
• For its size river has only modest flows
• Legal pacts signed in 1922 and 1944 allocated
  more water for human use in US and Mexico than
  the river can supply (even when no drought) and
  allocated no water for environmental purposes)
• Since 1960 river has rarely flowed fully to Gulf
  of California because of reduced water flow
  (dams), increased water withdrawals, and
  prolonged drought
• Major Pollution
• Reference p. 242

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Fig. 11-1, p. 238
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Fig. 11-2, p. 238
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• http//earthobservatory.nasa.gov/IOTD/view.php?id
  1288

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11-1 Will We Have Enough Usable Water?

• Concept 11-1A We are using available freshwater
  unsustainably by wasting it, polluting it, and
  charging too little for this irreplaceable
  natural resource.
• Concept 11-1B One of every six people does not
  have sufficient access to clean water, and this
  situation will almost certainly get worse.

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Importance and Availability of Water (1)

• Earth as a watery world saltwater covers about
  71 of the earths surface
• Water is one of our most poorly managed resources
• Water access is a global health issue
• 3900 children under 5 die every day from
  waterborne disease
• Water is an economic issue because it is vital
  for reducing poverty and producing food and energy

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Importance and Availability of Water (2)

• National and global security issue because of
  increasing tensions within and between nations
  over access to limited water resources
• Environmental issue because excessive withdrawal
  of water from rivers and aquifers results in
  dropping water tables, lower river flows,
  shrinking lakes, and losses of wetlands

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• Freshwater availability 0.024
• Groundwater
• Lakes
• Rivers
• Streams

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(No Transcript)
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Fig. 11-3, p. 240
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Groundwaterimportant terms to know

• Groundwater water that sinks into the soil and
  is stored in slowly flowing and slowly renewed
  underground reservoirs called aquifers
• Zone of saturation area where all available
  pores in soil and rock are filled by water
• Water table upper surface of the zone of
  saturation
• Aquifers porous, water saturated layers of
  sand, gravel, or bedrock that can yield an
  economically significant amount of water
• Natural recharge natural replenishment of an
  aquifer by precipitation that percolates downward
  through soil and rock
• Lateral recharge recharge occurring from the
  side by rivers and streams

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• http//www.eoearth.org/article/Aquifer

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Surface Water

• Surface runoff
• Watershed (drainage) basin
• Reliable runoff 1/3 of total
• Runoff use (worldwide)
• Domestic 10
• Agriculture 70
• Industrial 20

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Case Study Freshwater Resources in the United
States (1)

• Uneven distribution
• Contamination by agriculture and industry
• Eastern U.S.
• Western U.S.
• Groundwater withdrawal 50 of total use
• Drought prolonged period in which precipitation
  is at least 70 lower and evaporation is higher
  than normal in an area that is normally not dry

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Case Study Freshwater Resources in the United
States (2)

• Arid and semiarid West
• 85 of water to irrigate thirsty crops
• Water hot spots
• Southwest permanent drying by 2050
• Water tables dropping
• 36 states to face water shortages by 2013
  (drought, rising temps, pop growth, urban sprawl,
  and excessive use and waste of water)

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Fig. 11-4, p. 241
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Water hotspots in 17 Western states that, by
2025, could face intense conflicts over scarce
water needed for urban growth, irrigation,
recreation, and wildlife. Some analysts suggest
that this is a map of places not to live in the
forseeable future.
Washington
North Dakota
Montana
Oregon
Idaho
South Dakota
Wyoming
Nebraska
Nevada
Utah
Kansas
Colorado
California
Oklahoma
Arizona
New Mexico
Texas
Highly likely conflict potential
Substantial conflict potential
Moderate conflict potential
Unmet rural water needs
Fig. 11-5, p. 242
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Freshwater Shortages

• Causes of water scarcity
• Dry climate
• Drought
• Too many people
• Wasting water
• 2050 60 countries will face water stress
• 1 of 7 people no regular access to clean water
• Potential international conflicts over water

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Stress on the worlds major river basins, based
on a comparison of the amount of water available
with the amount used by humans.
Fig. 11-6, p. 243
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11-2 How Can We Increase Water Supplies?

• Concept 11-2A Groundwater used to supply cities
  and grow food is being pumped from aquifers in
  some areas faster than it is renewed by
  precipitation.
• Concept 11-2B Using dams, reservoirs, and
  transport systems to provide water to arid
  regions has increased water supplies in some
  areas, but has disrupted ecosystems and displaced
  people.

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11-2 How Can We Increase Water Supplies?

• Concept 11-2C We can convert salty ocean water
  to freshwater, but the cost is high, and the
  resulting salty brine must be disposed of without
  harming aquatic or terrestrial ecosystems.

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Increasing Freshwater Supplies

• Withdrawing groundwater
• Dams and reservoirs
• Transporting surface water
• Desalination
• Water conservation

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Trade-Offs
Withdrawing Groundwater
Advantages
Disadvantages
Useful for drinking and irrigation
Aquifer depletion from overpumping
Sinking of land (subsidence) from overpumping
Available year-round
Aquifers polluted for decades or centuries
Exists almost everywhere
Saltwater intrusion into drinking water supplies
near coastal areas
Renewable if not overpumped or contaminated
Reduced water flows into surface waters
No evaporation losses
Increased cost and contamination from deeper wells
Cheaper to extract than most surface waters
Fig. 11-7, p. 244
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Groundwater Withdrawal

• Most aquifers are renewable
• U.S. groundwater withdrawn 4X faster then its
  replenished
• Ogallala aquifer
• Californias Central Valley and agriculture

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Areas of greatest aquifer depletion from
groundwater overdraft in the continental United
States. Aquifer depletion in also high in Hawaii
and Puerto Rico (not shown).
Groundwater Overdrafts
High
Moderate
Minor or none
Fig. 11-8, p. 244
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Solutions
Groundwater Depletion
Control
Prevention
Raise price of water to discourage waste
Waste less water
Tax water pumped from wells near surface waters
Subsidize water conservation
Set and enforce minimum stream flow levels
Limit number of wells
Divert surface water in wet years to recharge
aquifers
Do not grow water-intensive crops in dry areas
Fig. 11-9, p. 245
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Science Focus Are Deep Aquifers the Answer?

• Could have enough water to supply billions of
  people for centuries
• Concerns
• Nonrenewable
• Geological and ecological impacts of pumping them
  is unknown
• No treaties to govern water rights
• Costs unknown and could be high

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Provides irrigation water above and below dam
Flooded land destroys forests or cropland
and displaces people
Large losses of water through evaporation
Provides water for drinking
Deprives downstream cropland and estuaries
of nutrient-rich silt
Reservoir useful for recreation and fishing
Risk of failure and devastating downstream floodin
g
Can produce cheap electricity (hydropower)
Reduces downstream flooding
Disrpupts migration and spawning of some fish
Fig. 11-10, p. 246
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Overtapped Colorado River Basin

• Only small amount reaches Gulf of California
• Threatened species
• Climate change will likely decrease flows
• Less water in Southwest
• Political and legal battles
• Silt behind dams not reaching delta and will
  eventually fill up reservoirs

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Hoover Dam completed (1935)
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Flow (billion cubic meters)
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Glen Canyon Dam completed (1963)
10
5
0
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
Year
Fig. 11-11, p. 247
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California Water Project

• Dams, pumps, aqueducts
• Southern California would otherwise be desert
• Climate change will reduce water availability in
  California
• People in southern California may have to move
• Groundwater already being depleted

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CALIFORNIA
NEVADA
Shasta Lake
UTAH
Sacramento River
Oroville Dam and Reservoir
Feather River
Lake Tahoe
North Bay Aqueduct
Sacramento
San Francisco
Hoover Dam and Reservoir (Lake Mead)
South Bay Aqueduct
Fresno
San Joaquin Valley
San Luis Dam and Reservoir
Colorado River
Los Angeles Aqueduct
California Aqueduct
ARIZONA
Colorado River Aqueduct
Santa Barbara
Central Arizona Project
Los Angeles
Phoenix
Salton Sea
San Diego
Tucson
MEXICO
Fig. 11-12, p. 247
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Aral Sea Disaster (1)

• Large-scale water transfers in dry central Asia
• Water loss and salinity increase
• Wetland destruction and wildlife
• Fish extinctions hurt fishing industry

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Aral Sea Disaster (2)

• Wind-blown salt
• Water pollution
• Climatic changes
• Restoration efforts

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1976
2006
Satellite photos show the sea in 1976 and in 2006.
Stepped Art
Fig. 11-13, p. 248
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Aral Sea

• http//www.youtube.com/watch?v9HfkZXLRYu8
• http//www.youtube.com/watch?vZ0Pi61SyVSMfeature
  fvwrel

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Removing Salt from Seawater

• Desalination
• Distillation
• Reverse osmosis
• 13,000 plants in 125 countries

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Major Problems with Desalination

• High cost
• Death of marine organisms
• Large quantity of brine wastes

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11-3 How Can We Use Water More Sustainably?

• Concept 11-3 We can use water more sustainably
  by cutting water waste, raising water prices,
  slowing population growth, and protecting
  aquifers, forests, and other ecosystems that
  store and release water.

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Reducing Water Waste (1)

• Benefits of water conservation
• Worldwide 65-70 loss
• Evaporation, leaks
• Can be reduced to 15
• Increase the cost of water use
• End subsidies for wasteful water use
• Provide subsidies for efficient water use

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Reducing Water Waste (2)

• Improve irrigation efficiency
• Center pivot
• Low-pressure sprinkler
• Precision sprinklers
• Drip irrigation
• Use less in homes and businesses

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Stepped Art
Fig. 11-14, p. 251
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Fig. 11-16, p. 252
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Solutions
Sustainable Water Use
Waste less water and subsidize water conservation
Do not deplete aquifers
Preserve water quality
Protect forests, wetlands, mountain glaciers,
watersheds, and other natural systems that store
and release water
Get agreements among regions and countries
sharing surface water resources
Raise water prices
Slow population growth
Fig. 11-17, p. 253
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Fig. 11-18, p. 253
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11-4 How Can We Reduce the Threat of Flooding?

• Concept 11-4 We can lessen the threat of
  flooding by protecting more wetlands and natural
  vegetation in watersheds and by not building in
  areas subject to frequent flooding.

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Benefits of Floodplains

• Highly productive wetlands
• Provide natural flood and erosion control
• Maintain high water quality
• Recharge groundwater
• Fertile soils
• Nearby rivers for use and recreation
• Flatlands for urbanization and farming

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Floods

• Deposit rich soils on floodplains
• Deadly and destructive
• Human activities worsen floods
• Failing dams and water diversion
• Hurricane Katrina and the Gulf Coast
• Climate change will increase coastal flooding

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Fig. 11-19, p. 254
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Case Study Floodplains of Bangladesh

• Dense population on coastal floodplain
• Moderate floods maintain fertile soil
• Increased frequency of large floods
• Development in the Himalayan foothills
• Destruction of coastal wetlands

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Solutions
Reducing Flood Damage
Prevention
Control
Preserve forests on watersheds
Straighten and deepen streams (channelization)
Preserve and restore wetlands in floodplains
Build levees or floodwalls along streams
Tax development on floodplains
Use floodplains primarily for recharging
aquifers, sustainable agriculture and forestry
Build dams
Fig. 11-20, p. 256
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11-5 How Can We Deal with Water Pollution?

• Concept 11-5A Streams can cleanse themselves of
  many pollutants if we do not overload them or
  reduce their flows.
• Concept 11-5B Reducing water pollution requires
  preventing it, working with nature in treating
  sewage, cutting resource use and waste, reducing
  poverty, and slowing population growth.

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Water Pollution Sources

• Point sources
• Discharge at specific locations
• Easier to identify, monitor, regulate
• Nonpoint sources
• Broad, diffuse areas
• Runoff of chemicals and sediment
• Agriculture
• Control is difficult and expensive

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Table 11-1, p. 257
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Stream Pollution

• Natural recovery processes
• Oxygen sag curve
• Effective regulations in the U.S.
• Problems in developing countries

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Dilution and decay of degradable,
oxygen-demanding wastes (or heated water) in a
stream, showing the oxygen sag curve (blue) and
the curve of oxygen demand (red)
Point source
Normal clean water organisms(Trout, perch,
bass,mayfly, stonefly)
Pollutant- tolerant fishes (carp, gar)
Fish absent, fungi, sludge worms, bacteria
(anaerobic)
Pollutant- tolerant fishes (carp, gar)
Normal clean water organisms (Trout, perch,
bass, mayfly, stonefly)
8 ppm
Types of organisms
8 ppm
Dissolved oxygen (ppm)
Clean Zone
Biological oxygen demand
Recovery Zone
Septic Zone
Decomposition Zone
Clean Zone
Fig. 11-21, p. 258
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Highly polluted river in China.
Fig. 11-22, p. 259
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Individuals Matter John Beal p. 258

• Restored Hamm Creek in Washington State
• Persuaded companies to stop polluting the creek,
  hauled out many truckloads of trash, began 15 yr
  project of planting thousands of trees along
  streams banks, also restored natural waterfalls
  and salmon spawning beds
• Outstanding example of Stewardship based on the
  idea that All sustainability is local
• http//www.youtube.com/watch?v5smNWchqo6o

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Lake Pollution

• Dilution less effective than with streams
• Stratification
• Low flow
• Lakes are more vulnerable than streams
• Eutrophication natural aging process
• Oligotrophic

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Cultural Eutrophication

• Nitrate- and phosphate-containing effluents
• Dense colonies of plants, algae, cyanobacteria
• Can lead to die-off of fish and other animals
• Prevent by limiting phosphate and nitrate use
• Lakes can be cleaned, and can recover

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Groundwater Pollution (1)

• Pollution sources
• Slow flow, dilution, dispersion
• Low dissolved oxygen
• Fewer bacteria
• Cooler temperatures

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Groundwater Pollution (2)

• Long time scale for natural cleansing
• Degradable wastes organic matter
• Slowly degradable wastes DDT
• Nondegradable wastes lead, arsenic

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Polluted air
Hazardous waste injection well
Pesticides and fertilizers
Deicing road salt
Coal strip mine runoff
Buried gasoline and solvent tanks
Cesspool, septic tank
Gasoline station
Pumping well
Water pumping well
Waste lagoon
Sewer
Landfill
Leakage from faulty casing
Accidental spills
Discharge
Confined aquifer
Unconfined freshwater aquifer
Groundwater flow
Confined freshwater aquifer
Fig. 11-23, p. 260
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Extent of Groundwater Pollution

• Global scale not much known
• Monitoring is very expensive
• Underground fuel tank leakage
• Arsenic
• Protecting groundwater prevention is best and
  least expensive

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Solutions
Groundwater Pollution
Prevention
Cleanup
Pump to surface, clean, and return to
aquifer (very expensive)
Find substitutes for toxic chemicals
Keep toxic chemicals out of the environment
Install monitoring wells near landfills and
underground tanks
Inject microorganisms to clean up
contamination (less expensive but still costly)
Require leak detectors on underground tanks
Ban hazardous waste disposal in landfills and
injection wells
Store harmful liquids in aboveground tanks with
leak detection and collection systems
Pump nanoparticles of inorganic compounds
to remove pollutants (still being developed)
Fig. 11-24, p. 261
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Purifying Drinking Water

• Developed countries
• Reservoir storage
• Purification plant
• Developing countries without purification plants
• Clear plastic bottle in sun, with black side
• http//www.grilink.org/sunwater.htm
• LifeStraw

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The Lifestraw, designed by Torben Vestergaard
Frandsen http//www.youtube.com/watch?featurefvwp
NR1vfZwe5B8FaoU
Fig. 11-25, p. 263
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Science Focus Is Bottled Water the Answer?

• 500-1000 times the cost of tap water
• Americans spent 15 billion in 2007
• About 1/4 is ordinary tap water
• About 40 of bottled water contaminated
• Water testing standards lower than for tap water
• Environment energy use, pollution

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Bottled Water

• http//www.mnn.com/food/healthy-eating-recipes/sto
  ries/5-reasons-not-to-drink-bottled-water

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Ocean Pollution

• Coastal areas highly productive ecosystems
• Occupied by 40 of population
• Coastal populations will double by 2050
• About 80 marine pollution originates on land
• Ocean dumping controversies
• Algal blooms
• Oxygen-depleted zones

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Urban sprawl Bacteria and viruses from sewers and
septic tanks contaminate shellfish beds and close
beaches runoff of fertilizer from lawns
adds nitrogen and phosphorus.
Cities Toxic metals and oil from streets
and parking lots pollute waters sewage adds
nitrogen and phosphorus.
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 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. 11-26, p. 263
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Pacific Garbage Patch

• http//www.youtube.com/watch?vSQh898IcOgMfeature
  related

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Science Focus Oxygen Depletion in the Northern
Gulf of Mexico

• Mouth of Mississippi River in spring and summer
• Suffocates fish, crab, shrimp
• Cultural eutrophication
• Caused by fertilizer use in Mississippi watershed
• Need less and more intelligent use of fertilizers
• Need better flood control

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A large zone of oxygen-depleted water forms each
year during the spring and summer in the Gulf of
Mexico as a result of oxygen-depleting algal
blooms. Evidence indicates that it is created
mostly by huge inputs of nitrate plant nutrients
from farms, cities, factories, and sewage
treatment plants in the vast Mississippi River
basin.
Stepped Art
Fig. 11-A, p. 265
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Case Study Ocean Pollution from Oil

• Crude and refined petroleum
• Tanker accidents Exxon Valdez
• Urban and industrial runoff is largest source

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Effects of Oil Pollution on Ocean Ecosystems

• Volatile organic hydrocarbons
• Kill larvae
• Destroy natural insulation and buoyancy of birds
  and mammals
• Heavy oil
• Sinks and kills bottom organisms
• Coral reefs die

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Gulf of Mexico Oil Spill

• http//www.youtube.com/watch?v8Uax5FRWnvsfeature
  related

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Oil Cleanup Methods

• Current methods recover no more than 15
• Prevention is most effective method
• Control runoff
• Double-hull tankers

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Solutions
Coastal Water Pollution
Prevention
Cleanup
Improve oil-spill cleanup capabilities
Reduce input of toxic pollutants
Separate sewage and storm lines
Use nanoparticles on sewage and oil spills
to dissolve the oil or sewage (still under
development)
Ban dumping of wastes and sewage by ships
in coastal waters
Ban ocean dumping of sludge and hazardous dredged
material
Require secondary treatment of coastal sewage
Regulate coastal development, oil drilling, and
oil shipping
Use wetlands, solar-aquatic, or other methods to
treat sewage
Require double hulls for oil tankers
Fig. 11-27, p. 264
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Preventing Nonpoint Source Pollution (1)

• Mostly agricultural waste
• Use vegetation to reduce soil erosion
• Reduce fertilizer use

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Preventing Nonpoint Source Pollution (2)

• Use plant buffer zones around fields and animal
  feedlots
• Keep feedlots away from slopes, surface water,
  and flood zones
• Integrated pest management
• Organic farming methods

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Laws for Reducing Point Source Pollution

• Clean Water Act
• Water Quality Act
• Discharge trading controversies
• Cap-and-trade of pollutants

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Case Study Reducing Water Pollution from Point
Sources in the U.S.

• Impressive achievements since 1972 law
• Bad news 2006 survey
• 45 of lakes and 40 of streams too polluted for
  fishing and swimming
• Runoff polluting 7 of 10 rivers
• Fish caught in 1/4 of waterways unsafe to eat
• Gasoline storage tanks tens of thousands leaking

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Sewage Treatment Systems

• Rural and suburban areas septic tanks
• Urban areas wastewater treatment plants
• Primary sewage treatment physical process
• Secondary sewage treatment biological process
• Chlorination bleaching and disinfection

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Primary and secondary sewage treatment.
Secondary
Primary
Chlorine disinfection tank
Settling tank
Aeration tank
Settling tank
Bar screen
Grit chamber
To river, lake, or ocean
Sludge
Raw sewage from sewers
(kills bacteria)
Activated sludge
Air pump
Disposed of in landfill or ocean or applied to
cropland, pasture, or rangeland
Sludge digester
Sludge drying bed
Fig. 11-28, p. 268
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Improving Sewage Treatment

• Systems that exclude hazardous and toxic
  chemicals
• Require businesses to remove harmful chemicals
  before sewage sent to treatment plant
• Reduce or eliminate use of toxic chemicals
• Composting toilet systems
• Wetland-based sewage treatment

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Science Focus Treating Sewage by Working with
Nature

• Living machines
• Tanks with increasingly complex organisms
• Artificially created wetlands
• Scientific principles of sustainability

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Fig. 11-29, p. 269
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Fig. 11-30, p. 269
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Three Big Ideas from This Chapter - 1

• One of the worlds major environmental problems
  is the growing shortages of freshwater in parts
  of the world.

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Three Big Ideas from This Chapter - 2

• We can use water more sustainably by cutting
  water waste, raising water prices, slowing
  population growth, and protecting aquifers,
  forests, and other ecosystems that store and
  release water.

96
Three Big Ideas from This Chapter - 3

• Reducing water pollution requires preventing it,
  working with nature in treating sewage, cutting
  resource use and waste, reducing poverty, and
  slowing population growth.