Water Pollution

G. Tyler Miller’sLiving 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 qualityBacterial Counts: Fecal

coliform counts from intestines of animals

• None per 100 ml for drinking• >200 per 100 ml for

swimmingSources: 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 qualityDissolved 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

Nonpoint sources

Water quality

Refer to Tables 22-1 and 22-2 p. 492 and 493

Fig. 22-3 p. 494

Point and Nonpoint SourcesNONPOINT SOURCES

Urban streets

Suburban development

Wastewater treatment plant

Rural homes

Cropland

Factory

Animal feedlot

POINT SOURCES

Fig. 22-4 p. 494

Major Sources of Water PollutionAgriculture: 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 PollutionFlowing 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 WorldsDeveloped CountriesU.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 PollutionDilution 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 LakesEutrophication: 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 LakesSolutions:• 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?

GroundwaterGroundwater 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

Cold temperatures

Coal strip mine runoff

Pumping well

Waste lagoon

Accidental spills

Groundwater flow

Confined aquifer

Discharge

Leakage from faulty casing

Hazardous waste injection wellPesticides

Gasoline station

Buried gasoline and solvent tank

Sewer

Cesspool septic tank

De-icing road salt

Unconfined freshwater aquifer

Confined freshwater aquifer

Water pumping well Landfill

Low oxygen

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

Leak detection systems

Strictly regulating hazardous waste disposal

Store hazardous materials above ground

Find less hazardous substitutes

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 PollutionOceans 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 O2Fig. 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 Point SourcesReduce runoffBuffer zone

vegetationReduce soil erosion

Clean Water Act

Water Quality Act

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 SystemsRequire suitable soils and maintenance

Fig. 22-15 p. 510

•¼ of all U.S. homes have Septic tanks

•Can be used in parking lots, business parks, etc.

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 TreatmentPhysical 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 processesRemoves nitrate and phosphateExpensive

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

Safe Drinking Water Act

Maximum contaminant levels (MCLs)

Purification of urban drinking water

Bottled water

Protection from terrorism

Purification of rural drinking water

Purification of urban drinking waterSurface 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 WaterU.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 Water1.4 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