Water Pollution
G. Tyler Miller’s
Living in the Environment
14th Edition
Chapter 22
Water, Air, Land ….
The solution to
pollution is
dilution.
Chapter 22 Key Concepts
 Types, sources, and effects of water pollutants
 Major pollution problems of surface water
 Major pollution problems of groundwater
 Reduction and prevention of water pollution
 Drinking water quality
Water
makes
us
unique
and
gives
life to
Earth.
Section 1 Key Ideas
• What are major types and effects of water
pollution?
• How do we measure water quality?
• Point versus Nonpoint sources
• What are the major sources of pollution?
What is water pollution?
Any chemical, biological,
or physical change in
water quality that has a
harmful effect on living
organisms or makes
water unsuitable for
desired usage.
What is water pollution?
WHO:
• 3.4 million premature
deaths each year from
waterborne diseases
• 1.9 million from
diarrhea
• U.S. 1.5 million
illnesses
• 1993 Milwaukee
370,000 sick
What is water pollution?
Need to study Table 22-1 Page 492
Infectious Agents: bacteria and viruses often
from animal wastes
Oxygen Demanding Wastes: organic waste that
needs oxygen often from animal waste, paper
mills and food processing.
Inorganic Chemicals: Acids and toxic chemicals
often from runoff, industries and household
cleaners
What is water pollution?
Organic Chemicals: oil, gasoline, plastics,
detergents often from surface runoff, industries
and cleaners
Plant Nutrients: water soluble nitrates, ammonia
and phosphates often from sewage, agriculture
and urban fertilizers
Sediment: soils and silts from land erosion can
disrupt photosynthesis, destroy spawning
grounds, clog rivers and streams
Heat Pollution and Radioactivity: mostly from
powerplants
How do we measure water quality
Bacterial Counts: Fecal
coliform counts from
intestines of animals
• None per 100 ml for
drinking
• >200 per 100 ml for
swimming
Sources: human sewage,
animals, birds, raccoons, etc.
See table 22-2 on page 493 for
diseases transmitted by
contaminated drinking water.
How do we measure water quality
Dissolved Oxygen: BOD
Biological Oxygen
Demand…the amount
of oxygen consumed by
aquatic decomposers
Chemical Analysis:
looking for presence of
inorganic or organic
chemicals
Suspended Sediment
water clarity
How do we measure water quality
Indicator Species:
organisms that give an
idea of the health of the
water body.
• Mussels, oysters and
clams filter water
Types, Effects and Sources of Water
Pollution
Point sources
Refer to Tables 22-1 and
22-2 p. 492 and 493
Nonpoint sources
Fig. 22-3 p. 494
Water quality
Point and Nonpoint Sources
NONPOINT SOURCES
Rural homes
Cropland
Urban streets
Animal feedlot
Suburban
development
POINT
SOURCES
Factory
Wastewater
treatment
plant
Fig. 22-4 p. 494
Major Sources of Water Pollution
Agriculture: by far the
leader
• Sediment, fertilizers,
bacteria from livestock,
food processing, salt from
soil irrigation
Industrial: factories and
powerplants
Mining: surface mining
toxics, acids, sediment
Section 2-3 Key Ideas
• Freshwater pollution: What are major
problems in streams?
• Developed versus Developing Countries
• Lake Pollution: Why are lakes and reservoirs
more vulnerable?
• What is Eutrophication?
Freshwater Stream Pollution
Flowing streams can recover from
moderate level of degradable
water pollution if their flows are
not reduced.
• Natural biodegradation
process
• Does not work if
overloaded or stream flow
reduced
• Does not work against non
biodegradable pollutants
Pollution of Streams
 Oxygen sag curve  Factors influencing recovery
Fig. 22-5 p. 496
What factors will influence this oxygen sag curve?
Two Worlds
Developed Countries
U.S. and other developed
countries sharply reduced
point sources even with
population and economic
growth
• Nonpoint still a problem
• Toxic chemicals still
problem
• Success Cuyahoga River,
Thames River
Two Worlds
Developing Countries:
Serious and growing
problem
• Half of world’s 500 major
rivers heavily polluted
• Sewage treatment
minimal $$$
• Law enforcement difficult
• 10% of sewage in China
treated
• Economic growth with
little $$$ to clean up
India’s Ganges River
• Holy River (1 million take
daily holy dip)
• 350 million (1/3rd of pop) live
in watershed
• Little sewage treatment
• Used for bathing, drinking etc.
• Bodies (cremated or not)
thrown in river
• Good news is the Indian
government is beginning to
work on problem
Freshwater Lake Pollution
Dilution as a solution in
lakes less effective
• Little vertical mixing
• Little water flow
(flushing)
Makes them more
vulnerable
• Toxins settle
• Kill bottom life
• Atmospheric deposition
• Food chain disruptions
Biomagnifications
of PCBs in an
aquatic food
chain from the
Great Lakes.
See figure 22-6 on
page 498
Eutrophication of Lakes
Eutrophication: nutrient
enrichment of lakes
mostly from runoff of
plant nutrients (nitrates
and phosphates)
• During hot dry weather can
lead to algae blooms
• Decrease of photosynthesis
• Dying algae then drops DO
levels
• Fish kills, bad odor
Pollution of Lakes
Eutrophication
Fig. 22-7 p. 499
Eutrophication in Lakes
Solutions:
• Advanced sewage
treatment (N, P)
• Household detergents
• Soil conservation
• Remove excess weed
build up
• Pump in oxygen or
freshwater
Case Study: The Great Lakes
•Pollution levels
dropped, but
long way to go
•95% of U.S.
freshwater
•30% Canadian
pop, 14% U.S.
•38 million drink
•1% flow out St.
Lawrence
•Toxic fish
Section 4: Groundwater
• Why is groundwater pollution a serious
problem?
• What is the extent of the problem?
• What are the solutions?
Groundwater
Groundwater can become
contaminated
• No way to cleanse itself
• Little dilution and
dispersion
• Out of sight pollution
• Prime source for
irrigation and drinking
• REMOVAL of pollutant
difficult
Groundwater Pollution: Causes
 Low flow rates  Few bacteria
 Low oxygen
 Cold temperatures
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. 22-9 p. 502
Groundwater
• Pollution moves in
plumes
• Soil, rocks, etc. act
like sponge
• Cleansing does not
work (low O, low
flow, cold)
• Nondegradables may
be permanent
Prevention is the
most effective and
cheapest
Groundwater Pollution Prevention
 Monitor aquifers
 Find less hazardous substitutes
 Leak detection systems
 Strictly regulating hazardous waste disposal
 Store hazardous materials above ground
Section 5 Ocean Pollution
• How much pollution can the oceans tolerate?
• Coastal zones: How does pollution affect
coastal zones?
• What are major sources of ocean pollution and
what is being done?
• Oils spills
Ocean Pollution
Oceans can disperse and
break down large
quantities of degradable
pollution if they are not
overloaded.
• Pollution worst near heavily
populated coastal zones
• Wetlands, estuaries, coral
reefs, mangrove swamps
• 40% of world’s pop. Live
within 62 miles of coast
Mangrove Swamp
Estuaries
Ocean Pollution
• Large amounts of untreated
raw sewage (viruses)
• Leaking septic tanks
• Runoff
• Algae blooms from
nutrients
• Dead zones NO DO
• Airborne toxins
• Oil spills
Ocean Pollution
Fig. 22-11 p. 504
Case Study: Chesapeake Bay
 Largest US
estuary
 Relatively shallow
 Slow “flushing”
action to Atlantic
 Major problems with dissolved O2
Fig. 22-13 p. 506
Preventing and
reducing the
flow of
pollution from
land and from
streams
emptying into
the ocean is
key to
protecting
oceans
Oil Spills
 Sources: offshore wells, tankers, pipelines and
storage tanks
 Effects: death of organisms, loss of animal
insulation and buoyancy, smothering
 Significant economic impacts
 Mechanical cleanup methods: skimmers and
blotters
 Chemical cleanup methods: coagulants and
dispersing agents
Oil Spills
Section 6: Prevention and
Reduction
• How can we reduce surface water pollution:
point and also nonpoint.
• How do sewage treatment plants work?
• How successful has the U.S. been at reducing
water pollution? Clean Water Act
Solutions: Preventing and Reducing
Surface Water Pollution
Nonpoint Sources
Reduce runoff
Buffer zone
vegetation
Point Sources
Clean Water Act
Water Quality Act
Reduce soil erosion
 Only apply pesticides and fertilizers as needed
Nonpoint Sources
Reduce runoff
Nonpoint Sources
Buffer Zones Near
Streams
Nonpoint
Prevent soil erosion and only apply
needed pesticides and fertilizers
Point Sources
Most developed countries
use laws to set water
pollution standards.
Federal Water Pollution
Control Act (Clean
Water Act 1972, ’77,
’87)
• Regulates navigable
waterways..streams,
wetlands, rivers, lake
Clean Water Act
• Sets standards for key
pollutants
• Requires permits for
discharge
• Requires sewage treatment
• Require permits for
wetland destruction
• Does not deal with
nonpoint sources well
• Goal All Waterways
fishable and swimable
Technological Approach: Septic
Systems
Require suitable soils and maintenance
•¼ of all U.S. homes
have Septic tanks
•Can be used in
parking lots, business
parks, etc.
Fig. 22-15 p. 510
Combined sewer
overflow is a
problem in many
older towns
•EPA: 1.8 M to
3.85 M sick from
swimming in
water
contaminated by
sewer overflows
•EPA: $100 billion
to fix
Technological Approach: Sewage
Treatment
Physical and biological treatment
Fig. 22-16 p. 511
Primary: removes 60% of
solids and 30-40% oxygen
demanding wastes
(physically)
Secondary: uses biological
processes to remove up to
90% of biodegradables
Tertiary: advanced
techniques only used in 5%
of U.S. $$$$
Disinfection: chlorine,
ozone, UV
What is not taken out???
Technological Approach: Advanced
(Tertiary) Sewage Treatment
Uses physical and chemical processes
Removes nitrate and phosphate
Expensive
Not widely used
Sludge disposal…using as fertilizer
Technological Approach: Using
Wetlands to Treat Sewage
Fig. 22-18 p. 513
The Good News
Largely thanks to CWA:
• Between 1972 – 2002
fishable and swimmable
streams 36% to 60%
• 74% served by sewage
treatment
• Wetlands loss dropped by
80%
• Topsoil losses dropped by 1
billion tons annually
The Bad News
• 45% of Lakes, 40% streams
still not fishable and
swimmable
• Nonpoint sources still huge
problem
• Livestock and Ag. Runoff
• Fish with toxins
Section 7 Drinking Water
• How is drinking water purified? High tech
way.
• How can we purify drinking water in
developing nations?
• What is the Safe Drinking Water Act?
• Is bottled water a good answer or an expensive
rip-off?
Drinking Water Quality
 Purification of urban drinking water
 Protection from terrorism
 Purification of rural drinking water
 Safe Drinking Water Act
 Maximum contaminant levels (MCLs)
 Bottled water
Purification of urban drinking
water
Surface Water: (like
Delaware River)
• Removed to reservoir to
improve clarity
• Pumped to a treatment
plant to meet drinking
water standards
Groundwater: often does
not need much
treatment
Purification of rural drinking
water
There can be simple ways
to purify water:
• Exposing to heat and UV
rays
• Fine cloths to filter water
• Add small amounts of
chlorine
Safe Drinking Water Act
• 54 countries have
drinking water laws
SDWA passed 1974
requires EPA to set
drinking water
standards
Maximum Contaminating
Levels (MCLs)
Safe Drinking Water Act
• Privately owned wells
exempt from SDWA
SDWA requires public
notification of failing to
meet standards and fine.
MCLs often stated in
parts per million or
parts per billion
Bottle Water
U.S. has the world’s
safest tap water due to
billions of $$$ of
investment
Bottle water 240 to
10,000 times more
expensive than tap
water
25% of bottle water is tap
water
Bottle Water
1.4 million metric tons of
bottle thrown away
each year
Toxic fumes released
during bottling
Bottles made from oil
based plastics
Water does not need to
meet SDWA