Water Pollution - PowerPoint PPT Presentation

1 / 58
About This Presentation
Title:

Water Pollution

Description:

Chapter 21 Water Pollution – PowerPoint PPT presentation

Number of Views:560
Avg rating:3.0/5.0
Slides: 59
Provided by: you79
Category:

less

Transcript and Presenter's Notes

Title: Water Pollution


1
Chapter 21
  • Water Pollution

2
Chapter Overview Questions
  • What are the causes and effects of water
    pollution?
  • 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?
  • How can we best deal with water pollution?

3
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)

4
Leading causes of Water pollution
  • Agricultural activities
  • Sediment erosion, fertilizers, pesticides,
    bacteria from livestock
  • Industrial facilities
  • Organic and inorganic chemicals
  • Mining
  • Sediment erosion, runoff of toxic chemicals

5
Plastics
  • New form of water pollution
  • Polymers break down very slowly and
  • in the process pollute many waterways
  • Harmful to
  • wildlife

http//fojailnohel.wordpress.com/2009/04/18/plasti
c-pollution-in-sea-water/
6
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.

7
Water Pollution Problems in Streams
  • Dilution and decay of degradable,
    oxygen-demanding wastes and heat in a stream.

Figure 21-4
8

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)
Type 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
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
  • 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.

12
Global Outlook Stream Pollution in Developed
Countries
  • Water pollution control laws enacted in the 70s
    increased the number and quality of water
    treatment plants and required industries to
    reduce point-source pollution

http//jalcorn.net/weblog/categories/9-Cleveland,-
OH
In 1969 this River caught fire Click on the
picture to read more
13
Global Outlook Stream Pollution in Developing
Countries
  • Untreated sewage and industrial wastes are a
    serious and growing problem.
  • Most cant afford to build waste treatment plants
  • The same water is used for drinking water,
    bathing, and washing clothes

Figure 21-5
14
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.
  • 300 million people do not have access to
    drinkable water.

Figure 21-5
15
Case Study Indias Ganges River Religion,
Poverty, and Health
  • Religious beliefs, cultural traditions, poverty,
    a large population cause severe pollution
  • Very little of the sewage is treated.
  • Hindu believe in cremating the dead 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.

16
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
17
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.

18
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.

19
http//lincoln.ne.gov/city/pworks/watrshed/educate
/fertiliz/index.htm
20
POLLUTION OF GROUNDWATER
  • Groundwater can become contaminated with a
    variety of organic and inorganic substances
    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

Exposure to infections disease through
contaminated drinking water is a major water
pollution problem
Table 21-2, p. 495
22
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
23

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
24
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.

25

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
26
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.

27
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.

28
  • Preventing contamination is the least expensive
    and most effective way to protect groundwater
    resources.

Fig. 21-9, p. 504
29
Ways to purify Drinking Water
http//marketplace.publicradio.org/display/web/200
8/05/23/waterworks
  • Water purification plants
  • Developed countries
  • Nanofilters
  • Reusable low cost
  • water filters
  • Lifestraw

http//www.thebluesun.co.uk/lifestraw.htm
30
Ways to purify Drinking Water
Solar disinfection method
http//www.drinking-water.org/html/en/ImageView/00
000295.html
http//doultonusa.com/doulton_water_filters/Emerge
ncy-treatment-of-drinking-water.htm
31
Is Bottled water the Answer?
  • Each year, consumers worldwide spend about 100
    billion on bottle water
  • The cost to provide access to safe drinking water
    for 1.1 billion people who now lack it would be
    11.9 billion
  • The number of plastic bottles thrown away in a
    year could circle the equator 8 times if lined up
    end to end
  • Back to the Tap movement based on boycotting
    bottled water

32
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.

33
OCEAN POLLUTION
  • Majority originates on land
  • Includes
  • Oil and other toxic chemicals
  • Solid wastes

http//www.oilgoneeasy.com/oil_spill_blog/index.ph
p/page/2
http//www.inhabitat.com/2009/08/28/great-pacific-
garbage-patch-is-worse-than-we-thought/
Click on the picture to learn more about the 2010
Oil Spill in the Gulf of Mexico
34
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.

35

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
36
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 on or
    near the coast.
  • The EPA has classified 4 of 5 estuaries as
    threatened or impaired.

37
OCEAN POLLUTION
  • Harmful algal blooms (HAB) are caused by
    explosive growth of harmful algae from sewage and
    agricultural runoff.

Figure 21-11
38
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
39

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
40
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
41

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
42
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.

43
How Would You Vote?
  • Discuss together keeping in mind that you must
    consider the ecological, economical and political
    viewpoints.
  • 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.

44
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 for
    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.

45
Reducing Water Pollution through Sewage Treatment
  • Septic tanks and various levels of sewage
    treatment can reduce point-source water pollution.

Figure 21-15
46
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.

47
Reducing Water Pollution through Sewage Treatment
  • Primary and Secondary sewage treatment.

Figure 21-16
48
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
49
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.

50
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.

51
How Would You Vote?
  • Discuss together keeping in mind that you
    must consider the ecological, economical and
    political viewpoints.
  • 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.

52
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.

53
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.

54
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.

55
How Would You Vote?
  • Discuss together keeping in mind that you
    must consider the ecological, economical and
    political viewpoints.
  • 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.

56
How Would You Vote?
  • Discuss together keeping in mind that you must
    consider the ecological, economical and political
    viewpoints.
  • 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
Write a Comment
User Comments (0)
About PowerShow.com