Water Pollution



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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
  • Nonpoint sources
  • Water quality
  • Refer to Tables 22-1 and 22-2 p. 492 and 493
  • Fig. 22-3 p. 494

Point and Nonpoint Sources

  • NONPOINT 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 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
  • Cold temperatures
  • Coal strip mine runoff
  • Pumping well
  • Waste lagoon
  • Accidental spills
  • Groundwater flow
  • Confined aquifer
  • Discharge
  • Leakage from faulty casing
  • Hazardous waste injection well
  • Pesticides
  • Gasoline station
  • Buried gasoline and solvent tank
  • Sewer
  • 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
  • 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 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
  • 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 Sources
  • Reduce runoff
  • Buffer zone vegetation
  • Reduce 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

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
  • 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
  • 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 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


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