Water Pollution

1
Chapter 21

• Water Pollution

2
Chapter Overview Questions

• What pollutes water, where do these pollutants
  come from, and what effects do they have?
• What are the major water pollution problems in
  streams and lakes?
• What causes groundwater pollution, and how can it
  be prevented?
• What are the major water pollution problems
  affecting oceans?

3
Chapter Overview Questions (contd)

• How can we prevent and reduce surface water
  pollution?
• How safe is drinking water, and how can it be
  made safer?

4
Updates Online

• The latest references for topics covered in this
  section can be found at the book companion
  website. Log in to the books e-resources page at
  www.thomsonedu.com to access InfoTrac articles.
• InfoTrac Cleaning Up an Effluent Society.
  Business Week Online, March 22, 2006.
• InfoTrac Nuclear Reactors Found to Be Leaking
  Radioactive Water. Matthew L. Wald. The New York
  Times, March 17, 2006 pA21(L).
• InfoTrac Water and farms towards sustainable
  use. Kevin Parris, Wilfrid Legg. OECD Observer,
  March 2006 i254 p14(3).
• WHO Arsenic in Drinking Water
• National Ocean Service Welcome to Nonpoint
  Source Pollution
• EPA Surface and Groundwater

5
Core Case Study Using Nature to Purify Sewage

• Ecological wastewater purification by a living
  machine.
• Uses the sun and a series of tanks containing
  plants, snails, zooplankton, crayfish, and fish
  (that can be eaten or sold for bait).

Figure 21-1
6
WATER POLLUTION SOURCES, TYPES, AND EFFECTS

• Water pollution is any chemical, biological, or
  physical change in water quality that has a
  harmful effect on living organisms or makes water
  unsuitable for desired uses.
• Point source specific location (drain pipes,
  ditches, sewer lines).
• Nonpoint source cannot be traced to a single
  site of discharge (atmospheric deposition,
  agricultural / industrial / residential runoff)

7

Table 21-2, p. 495
8
Major Water Pollutants and Their Effects

• A fecal coliform bacteria test is used to
  indicate the likely presence of disease-causing
  bacteria in water.

Figure 21-2
9
Major Water Pollutants and Their Effects

• Water quality and dissolved oxygen (DO) content
  in parts per million (ppm) at 20C.
• Only a few fish species can survive in water less
  than 4ppm at 20C.

Figure 21-3
10

Water Quality
DO (ppm) at 20C
Good
89
Slightly polluted
6.78
Moderately polluted
4.56.7
Heavily polluted
Below 4.5
Gravely polluted
Below 4
Fig. 21-3, p. 496
11
POLLUTION OF FRESHWATER STREAMS

• Flowing streams can recover from a moderate level
  of degradable water pollutants if they are not
  overloaded and their flows are not reduced.
• In a flowing stream, the breakdown of degradable
  wastes by bacteria depletes DO and creates and
  oxygen sag curve.
• This reduces or eliminates populations of
  organisms with high oxygen requirements.

12
Water Pollution Problems in Streams

• Dilution and decay of degradable,
  oxygen-demanding wastes and heat in a stream.

Figure 21-4
13

Normal clean water organisms (Trout, perch,
bass, mayfly, stonefly)
Trash fish (carp, gar, leeches)
Fish absent, fungi, sludge worms, bacteria (anae
robic)
Trash fish (carp, gar, leeches)
Clean Normal clean water organisms (Trout,
perch, bass, mayfly, stonefly)
Types of organisms
8 ppm
Dissolved oxygen (ppm)
8 ppm
Clean Zone
Biological oxygen demand
Recovery Zone
Septic Zone
Decomposition Zone
Clean Zone
Fig. 21-4, p. 497
14
POLLUTION OF FRESHWATER STREAMS

• Most developed countries have sharply reduced
  point-source pollution but toxic chemicals and
  pollution from nonpoint sources are still a
  problem.
• Stream pollution from discharges of untreated
  sewage and industrial wastes is a major problem
  in developing countries.

15
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 21-5
16
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.

17
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.

Figure 21-6
18
POLLUTION OF FRESHWATER LAKES

• Dilution of pollutants in lakes is less effective
  than in most streams because most lake water is
  not mixed well and has little flow.
• Lakes and reservoirs are often stratified and
  undergo little mixing.
• Low flow makes them susceptible to runoff.
• Various human activities can overload lakes with
  plant nutrients, which decrease DO and kill some
  aquatic species.

19
Cultural Eutrophication

• Eutrophication the natural nutrient enrichment
  of a shallow lake, estuary or slow moving stream,
  mostly from runoff of plant nutrients from the
  surrounding land.
• Cultural eutrophication human activities
  accelerate the input of plant nutrients (mostly
  nitrate- and phosphate-containing effluents) to a
  lake.
• 85 of large lakes near major population centers
  in the U.S. have some degree of cultural
  eutrophication.

20
POLLUTION OF GROUNDWATER

• Groundwater can become contaminated with a
  variety of chemicals because it cannot
  effectively cleanse itself and dilute and
  disperse pollutants.
• The drinking water for about half of the U.S.
  population and 95 of those in rural areas comes
  from groundwater.

21

Polluted air
Pesticides and fertilizers
Hazardous waste injection well
Deicing road salt
Coal strip mine runoff
Buried gasoline and solvent tanks
Gasoline station
Pumping well
Cesspool, septic tank
Water pumping well
Waste lagoon
Sewer
Leakage from faulty casing
Landfill
Accidental spills
Discharge
Unconfined freshwater aquifer
Confined aquifer
Confined freshwater aquifer
Groundwater flow
Fig. 21-7, p. 501
22
POLLUTION OF GROUNDWATER

• It can take hundreds to thousand of years for
  contaminated groundwater to cleanse itself of
  degradable wastes.
• Nondegradable wastes (toxic lead, arsenic,
  flouride) are there permanently.
• Slowly degradable wastes (such as DDT) are there
  for decades.

23

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. 21-8, p. 502
24
POLLUTION OF GROUNDWATER

• Leaks from a number of sources have contaminated
  groundwater in parts of the world.
• According the the EPA, one or more organic
  chemicals contaminate about 45 of municipal
  groundwater supplies.
• By 2003, the EPA had completed the cleanup of
  297,000 of 436,000 underground tanks leaking
  gasoline, diesel fuel, home heating oil, or toxic
  solvents.

25
Case Study Arsenic in Groundwater - a Natural
Threat

• Toxic Arsenic (As) can naturally occur at high
  levels in soil and rocks.
• Drilling into aquifers can release As into
  drinking water supplies.
• According to WHO, more than 112 million people
  are drinking water with As levels 5-100 times the
  10 ppb standard.
• Mostly in Bangladesh, China, and West Bengal,
  India.

26

Solutions
Groundwater Pollution
Cleanup
Prevention
Pump to surface, clean, and return to aquifer
(very expensive)
Find substitutes for toxic chemicals
Keep toxic chemicals out of the environment
Inject microorganisms to clean up contamination
(less expensive but still costly)
Install monitoring wells near landfills and
underground tanks
Require leak detectors on underground tanks
Pump nanoparticles of inorganic compounds to
remove pollutants (may be the cheapest, easiest,
and most effective method but is still being
developed)
Ban hazardous waste disposal in landfills and
injection wells
Store harmful liquids in aboveground tanks with
leak detection and collection systems
Fig. 21-9, p. 504
27
OCEAN POLLUTION

• Oceans, if they are not overloaded, can disperse
  and break down large quantities of degradable
  pollutants.
• Pollution of coastal waters near heavily
  populated areas is a serious problem.
• About 40 of the worlds population lives near on
  or near the coast.
• The EPA has classified 4 of 5 estuaries as
  threatened or impaired.

28

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. 21-10, p. 505
29
OCEAN POLLUTION

• Harmful algal blooms (HAB) are caused by
  explosive growth of harmful algae from sewage and
  agricultural runoff.

Figure 21-11
30
Oxygen Depletion in the Northern Gulf of Mexico

• A large zone of oxygen-depleted water forms for
  half of the year in the Gulf of Mexico as a
  result of HAB.

Figure 21-A
31

Missouri River
Mississippi River Basin
Ohio River
Mississippi River
MS
LA
LOUISIANA
Mississippi River
TX
Depleted oxygen
Gulf of Mexico
Gulf of Mexico
Fig. 21-A, p. 507
32
Case Study The Chesapeake Bay An Estuary in
Trouble

• Pollutants from six states contaminate the
  shallow estuary, but cooperative efforts have
  reduced some of the pollution inputs.

Figure 21-12
33
OCEAN OIL POLLUTION

• Most ocean oil pollution comes from human
  activities on land.
• Studies have shown it takes about 3 years for
  many forms of marine life to recover from large
  amounts of crude oil (oil directly from ground).
• Recovery from exposure to refined oil (fuel oil,
  gasoline, etc) can take 10-20 years for marine
  life to recover.

34
OCEAN OIL POLLUTION

• Tanker accidents and blowouts at offshore
  drilling rigs can be extremely devastating to
  marine life (especially diving birds, left).

Figure 21-13
35

Solutions
Coastal Water Pollution
Prevention
Cleanup
Reduce input of toxic pollutants
Improve oil-spill cleanup capabilities
Separate sewage and storm lines
Ban dumping of wastes and sewage by maritime and
cruise ships in coastal waters
Sprinkle nanoparticles over an oil or sewage
spill to dissolve the oil or sewage without
creating harmful by-products (still under
development)
Ban ocean dumping of sludge and hazardous dredged
material
Protect sensitive areas from development, oil
drilling, and oil shipping
Require at least secondary treatment of coastal
sewage
Regulate coastal development
Use wetlands, solar-aquatic, or other methods to
treat sewage
Recycle used oil
Require double hulls for oil tankers
Fig. 21-14, p. 509
36
PREVENTING AND REDUCING SURFACE WATER POLLUTION

• The key to reducing nonpoint pollution most of
  it from agriculture is to prevent it from
  reaching bodies of water.
• Farmers can reduce runoff by planting buffers and
  locating feedlots away from steeply sloped land,
  flood zones, and surface water.

37
How Would You Vote?

• To conduct an instant in-class survey using a
  classroom response system, access JoinIn Clicker
  Content from the PowerLecture main menu for
  Living in the Environment.
• Should we greatly increase efforts to reduce
  water pollution from nonpoint sources even though
  this could be quite costly?
• a. No. Most farmers and ranchers can't afford
  more regulations.
• b. Yes. Nonpoint source water pollution is a
  serious environmental and human health threat.

38
PREVENTING AND REDUCING SURFACE WATER POLLUTION

• Most developed countries use laws to set water
  pollution standards, but such laws rarely exist
  in developing countries.
• The U.S. Clean Water Act sets standards fro
  allowed levels of key water pollutants and
  requires polluters to get permits.
• EPA is experimenting with a discharge trading
  policy similar to that for air pollution control.

39
Reducing Water Pollution through Sewage Treatment

• Septic tanks and various levels of sewage
  treatment can reduce point-source water pollution.

Figure 21-15
40

Manhole cover (for cleanout)
Septic tank
Gas
Distribution box
Scum
Wastewater
Sludge
Drain field (gravel or crushed stone)
Vent pipe
Perforated pipe
Fig. 21-15, p. 510
41
Reducing Water Pollution through Sewage Treatment

• Raw sewage reaching a municipal sewage treatment
  plant typically undergoes
• Primary sewage treatment a physical process that
  uses screens and a grit tank to remove large
  floating objects and allows settling.
• Secondary sewage treatment a biological process
  in which aerobic bacteria remove as much as 90
  of dissolved and biodegradable, oxygen demanding
  organic wastes.

42
Reducing Water Pollution through Sewage Treatment

• Primary and Secondary sewage treatment.

Figure 21-16
43

Primary
Secondary
Chlorine disinfection tank
Grit chamber
Bar screen
Settling tank
Aeration tank
Settling tank
To river, lake, or ocean
Sludge
Raw sewage from sewers
(kills bacteria)
Activated sludge
Air pump
Sludge digester
Disposed of in landfill or ocean or applied to
cropland, pasture, or rangeland
Sludge drying bed
Fig. 21-16, p. 511
44
Reducing Water Pollution through Sewage Treatment

• Advanced or tertiary sewage treatment
• Uses series of chemical and physical processes to
  remove specific pollutants left (especially
  nitrates and phosphates).
• Water is chlorinated to remove coloration and to
  kill disease-carrying bacteria and some viruses
  (disinfect).

45
Reducing Water Pollution through Sewage Treatment

• Sewage sludge can be used as a soil conditioner
  but this can cause health problems if it contains
  infectious bacteria and toxic chemicals.
• Preventing toxic chemicals from reaching sewage
  treatment plants would eliminate such chemicals
  from the sludge and water discharged from such
  plants.

46

Odors Odors may cause illness or indicate
presence of harmful gases.
Dust Particles Particles of dried sludge carry
viruses and harmful bacteria that can be inhaled,
infect cuts or enter homes.
BUFFER ZONE
Exposure Children may walk or play in fertilized
fields.
Livestock Poisoning Cows may die after grazing
on sludge-treated fields.
Sludge
Groundwater Contamination Harmful chemicals and
pathogens may leach into groundwater and
shallow wells.
Surface Runoff Harmful chemicals and pathogens
may pollute nearby streams,lakes, ponds, and
wetlands.
Fig. 21-17, p. 513
47
How Would You Vote?

• To conduct an instant in-class survey using a
  classroom response system, access JoinIn Clicker
  Content from the PowerLecture main menu for
  Living in the Environment.
• Should we ban the discharge of toxic chemicals
  into pipes leading to sewage treatment plants?
• a. No. Many small businesses and manufacturers
  can't afford tougher regulations.
• b. Yes. Dangerous wastes are still being released
  into sewage treatment plants.

48
Reducing Water Pollution through Sewage Treatment

• Natural and artificial wetlands and other
  ecological systems can be used to treat sewage.
• California created a 65 hectare wetland near
  Humboldt Bay that acts as a natural wastewater
  treatment plant for the town of 16,000 people.
• The project cost less than half of the estimated
  price of a conventional treatment plant.

49
Reducing Water Pollution through Sewage Treatment

• Water pollution laws have significantly improved
  water quality in many U.S. streams and lakes but
  there is a long way to go.
• Some want to strengthen the U.S. Clean Water Act
  (CWA) to prevent rather than focusing on
  end-of-the-pipe removal.
• Many farmers and developers see the CWA as
  limiting their rights as property owners to fill
  in wetlands.

50
How Would You Vote?

• To conduct an instant in-class survey using a
  classroom response system, access JoinIn Clicker
  Content from the PowerLecture main menu for
  Living in the Environment.
• Should the U.S. Clean Water Act be strengthened?
• a. No. Many farmers, ranchers and small
  businesses can't afford additional regulations.
• b. Yes. It will further reduce pollution and
  protect the environment and human health.

51
DRINKING WATER QUALITY

• Centralized water treatment plants and watershed
  protection can provide safe drinking water for
  city dwellers in developed countries.
• Simpler and cheaper ways can be used to purify
  drinking water for developing countries.
• Exposing water to heat and the suns UV rays for
  3 hours can kill infectious microbes.

52
Using Laws to Protect Drinking Water

• While most developed countries have drinking
  water quality standards and laws, most developing
  countries do not.
• The U.S Safe Drinking Water Act requires the EPA
  to establish national drinking water standards
  (maximum contaminant levels) for any pollutant
  that may have adverse effects on human health.

53
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.
• Industry pressures to weaken the Safe Drinking
  Act
• Eliminate national tests and public notification
  of violations.
• Allow rights to pollute if provider cannot afford
  to comply.

54
How Would You Vote?

• To conduct an instant in-class survey using a
  classroom response system, access JoinIn Clicker
  Content from the PowerLecture main menu for
  Living in the Environment.
• Should the U.S. Safe Drinking Water Act be
  strengthened?
• a. No. Rural people, small businesses and
  manufacturers can't afford more regulations.
• b. Yes. Strengthening the Act would protect the
  environment and the health of millions of people.

55
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.

56
How Would You Vote?

• To conduct an instant in-class survey using a
  classroom response system, access JoinIn Clicker
  Content from the PowerLecture main menu for
  Living in the Environment.
• Should pollution standards be established for
  bottled water?
• a. No. Competition within the free market and the
  media would better solve the problems.
• b. Yes. Too many bottled waters contain bacteria
  and other dangerous contaminants.

57

Solutions
Water Pollution
Prevent groundwater contamination
Reduce nonpoint runoff
Reuse treated wastewater for irrigation
Find substitutes for toxic pollutants
Work with nature to treat sewage
Practice four R's of resource use (refuse,
reduce, recycle, reuse)
Reduce air pollution
Reduce poverty
Reduce birth rates
Fig. 21-18, p. 517
58

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.
Fig. 21-19, p. 517