1. APES Lesson 7 - Demogrphy
AP Environmental Science
Mr. Grant
Lesson 73
Solutions to Depletion of Fresh Water
&
Freshwater Pollution and Its Control

2. Mastery Check
Why are sources of freshwater unreliable for some people and plentiful for others?
The natural distribution of fresh water is very uneven in both space and time.

3. Objectives: Define the term desalination.
APES Lesson 72 - How We Use Water & Solutions to Depletion of Fresh Water
Objectives:
Define the term desalination.
Assess problems of water supply and propose solutions to address depletion of fresh water.

4. Define the term sinkhole.
APES Lesson 72 - How We Use Water & Solutions to Depletion of Fresh Water
Define the term sinkhole.
Desalination:
The removal of salt from seawater.

5. Privatization of water supplies is a much-debated issue.
APES Lesson 72 - How We Use Water & Solutions to Depletion of Fresh Water
Assess problems of water supply and propose solutions to address depletion of fresh water.
Desalination increases water supply, but is expensive and energy-intensive.
Solutions to reduce demand include technology, market-based approaches, and consumer products that increase efficiency in agriculture, industry, and the home.
Privatization of water supplies is a much-debated issue.
Political tensions over water may heighten in the future.

6. Solutions to Depletion of Fresh Water
Reducing demand is harder politically in the short term
International aid agencies are funding demand-based solutions over supply-based solutions
Offers better economic returns
Causes less ecological and social damage

7. Desalinization “makes” more fresh water
Desalination (desalinization) = the removal of salt from seawater or other water of marginal quality
Distilling = evaporates and condenses ocean water
Reverse osmosis = forces water through membranes to filter out salts

8. Desalinization “makes” more fresh water
Over 2000 desalinization facilities operate around the world, but there are problems with it
Is expensive
Requires large energy inputs (usually fossil fuels)
Kills aquatic life at the water intakes
Generates a concentrated salty waste

9. Agricultural demand can be reduced
Agriculture uses the largest amount of water of any use, but a number of measures can be taken to reduce waste
Line irrigation canals to prevent leaks
Level fields to reduce runoff
Use efficient irrigation methods
Low-pressure spray irrigation sprays water downward
Drip irrigation systems target individual plants
Match crops to land and climate
Eliminate water subsidies
Use selective breeding and genetic modification to produce crops that require less water

10. Agricultural demand can be reduced
APES Lesson 72 - How We Use Water & Solutions to Depletion of Fresh Water
Agricultural demand can be reduced
Line irrigation canals
Level fields to reduce runoff
Use efficient irrigation methods
Low-pressure spray irrigation sprays water downward
Drip irrigation systems target individual plants
Match crops to land and climate
Eliminate water subsidies
Selective breeding and genetic modification to produce crops that require less water
Eat less meat

11. We can lower residential and industrial water use
Residential water use can be cut in a number of ways
Install low-flow faucets, toilets, etc.
Rainwater harvesting = capturing rain from roofs
Gray water = wastewater from showers and sinks that can be used to water lawns
Xeriscaping = using plants adapted to arid conditions
Industries and municipalities can save water
Shift to processes that use less water
Recycle wastewater
Use surface water runoff to recharge aquifers
Find and patch leaky pipes

12. Residential demand can be reduced
APES Lesson 72 - How We Use Water & Solutions to Depletion of Fresh Water
Residential demand can be reduced
Xeriscaping uses plants adapted to arid conditions
Install low-flow faucets, showerheads, washing machines, and toilets
Rainwater harvesting = capturing rain from roofs
Gray water = wastewater from showers and sinks
Water lawns at night
We can save hundreds or thousands of gallons/day

13. Market-based approaches to water conservation are being debated
End government subsidies of inefficient practices
Let the price of water reflect its true cost of extraction
But since industrial uses are more profitable than agricultural uses, poorer, less developed countries suffer
Privatize water supplies: construction, maintenance, management, and ownership
May improve efficiency
Little incentive to provide access to the poor
Decentralization of water control may conserve water
Shift control to the local level

14. Nations often cooperate to resolve water disputes
Freshwater depletion leads to shortages, which can lead to conflict
261 major rivers cross national borders
Water is a key element in hostilities among Israel, Palestinians, and neighboring countries
Conflicts also exist between states in the United States
Many nations have cooperated with neighbors to resolve disputes
India has agreements to co-manage rivers with Pakistan, Bangladesh, Bhutan, and Nepal
European nations on the Rhine and Danube signed treaties

15. Will we see a future of water wars?

16. APES Lesson 73 - Fresh Water Polution and its Control & Wastewater and its Treatment
Describe the major classes of water pollution and propose solutions to address water pollution.
Water pollution stems from point sources and nonpoint sources.
Water pollutants include toxic chemicals, microbial pathogens, excessive nutrients, biodegradable wastes, sediment, and thermal pollution.
Groundwater pollution can be more persistent and difficult to address than surface water pollution.
Legislation and regulation have improved water quality in developed nations in recent decades.

17. Freshwater pollution and its control
APES Lesson 73 - Fresh Water Polution and its Control & Wastewater and its Treatment
Freshwater pollution and its control
Water for human consumption and other organisms needs to be:
Disease-free
Nontoxic
Half of the world’s major rivers are seriously depleted and polluted
They poison surrounding ecosystems
Threatening the health and livelihood of people
The invisible pollution of groundwater has been called a “covert crisis”

18. Freshwater Pollution and Its Control
People affect aquatic ecosystems and human health when we introduce toxic substances and diseases
Half of the world’s major rivers are seriously depleted and polluted
They degrade and poison surrounding ecosystems, threatening the health and livelihood of people
55% of U.S. streams and rivers are in poor condition
The invisible pollution of groundwater has been called a “covert crisis”
Preventing pollution is easier and more effective than mitigating it later

19. Water pollution comes from point and non-point sources
Pollution = the release of matter or energy that causes undesirable impacts on the health and well-being of humans or other organisms
Water pollution comes in many forms and causes diverse impacts
Point sources = discrete locations of water pollution
Factories, sewer pipes
Addressed by the U.S. Clean Water Act
Non-point sources = sources of pollution arising from multiple inputs over larger areas (farms, city streets, neighborhoods)
The major source of U.S. water pollution

20. Point and nonpoint sources of pollution
APES Lesson 73 - Fresh Water Polution and its Control & Wastewater and its Treatment
Point and nonpoint sources of pollution
Pollution = the release of matter or energy that causes undesirable impacts on the health and well-being of humans or other organisms
**Point sources = discrete locations of water pollution
Factories, sewer pipes**
Addressed by the U.S. Clean Water Act
Nonpoint sources = pollution arises from multiple inputs over larger areas (farms, city streets, neighborhoods)
The major source of U.S. water pollution

22. Water pollution takes many forms
Toxic chemicals: waterways have become polluted with toxic organic chemicals of our own making
Pesticides, petroleum products, synthetic chemicals; arsenic, lead, mercury, acid rain, acid
Effects include poisoned animals and plants, altered aquatic ecosystems, and decreased human health

23. APES Lesson 73 - Fresh Water Polution and its Control & Wastewater and its Treatment
Toxic chemicals
Pesticides, petroleum products, synthetic chemicals
Arsenic, lead, mercury, acid rain, acid drainage from mines
Effects include poisoned animals and plants, altered aquatic ecosystems, and decreased human health
Solutions:
Issue and enforce more stringent regulations of industry
Modify industrial processes
Modify our purchasing decisions
Many of these chemicals are potentially harmful and can spawn health problems.

24. Water pollution takes many forms
Scientists measure a range of water characteristics to assess water quality (color, pH, temperature, etc.)
Solutions:
Issue and enforce more stringent regulations
Modify industrial processes and our purchasing decisions to rely less on these substances

25. Pathogens and waterborne diseases
Viruses, protists, and bacteria enter water supplies through inadequately treated human waste and animal waste from feedlots
Fecal coliform bacteria indicate fecal contamination
Usually are not pathogenic organisms
Indicate that the water may hold other disease- causing pathogens (e.g., giardiasis, typhoid, hepatitis A)

26. Pathogens and waterborne diseases
Bacterial pollution causes more human health problems than any other type of water pollution
Conditions are improving, but 800 million people lack reliable access to safe water
Treating wastewater and personal hygiene reduce risks

27. Pathogens cause human health problems
APES Lesson 73 - Fresh Water Polution and its Control & Wastewater and its Treatment
Pathogens cause human health problems
1 billion are still without safe water
2.6 billion have inadequate sewer or sanitary facilities
Mostly rural Asians and Africans
Health impacts kill 5 million people per year
Solutions:
Disinfect drinking water
Treat sewage
Public education to encourage personal hygiene
Government enforcement of regulations protecting food
Pathogens that can be spread through drinking water

28. Nutrient pollution
Nutrient pollution from fertilizers, farms, sewage, lawns, golf courses leads to eutrophication
Fertilizers add phosphorus to water, which boosts algal and aquatic plant growth
Spreading algae cover the surface, decreasing sunlight
Bacteria eat dead algae, reducing dissolved oxygen
Fish and shellfish die

29. Nutrient pollution Areas of low oxygen can become “dead zones”
Solutions include treating wastewater
Reducing fertilizer application
Using phosphate-free detergents
Planting vegetation to increase nutrient uptake

30. APES Lesson 73 - Fresh Water Polution and its Control & Wastewater and its Treatment
Nutrient pollution
Nutrient pollution from fertilizers, farms, sewage, lawns, golf courses leads to eutrophication
Fertilizers add phosphorus to water, which boosts algal and aquatic plant growth
Spreading algae cover the surface, decreasing sunlight
Bacteria eat dead algae, reducing dissolved oxygen
Fish and shellfish die
Solutions include treating wastewater
Reducing fertilizer application
Using phosphate-free detergents
Planting vegetation to increase nutrient uptake
The Dümmer See, a lake in Germany's Lower Saxony, suffers from heavy nutrient pollution.

31. Eutrophication is a natural process, but…
APES Lesson 73 - Fresh Water Polution and its Control & Wastewater and its Treatment
Eutrophication is a natural process, but…
Human activities dramatically increase the rate at which it occurs

32. Biodegradable Wastes and Sediment
Introducing large amounts of biodegradable waste into water decreases dissolved oxygen
Wastewater = water affected by human activities; can be a source of biodegradable wastes
Sediment is the eroded material carried by rivers

33. Biodegradable wastes and Sediment
Clear-cutting, mining, clearing land for housing, and cultivating farm fields expose soil to erosion
It dramatically changes aquatic habitats
Fish may not survive
Solutions:
Better management of farms and forests
Avoid large-scale disturbance of vegetation

34. APES Lesson 73 - Fresh Water Polution and its Control & Wastewater and its Treatment
Sediment pollution
Sediment in rivers can impair aquatic ecosystems
Clear-cutting, mining, clearing land for housing, and cultivating farm fields expose soil to erosion
It dramatically changes aquatic habitats
Fish may not survive
Solutions:
Better management of farms and forests
Avoid large-scale disturbance of vegetation

35. Thermal pollution Water that is too warm causes problems
Warmer water holds less oxygen
Dissolved oxygen decreases as temperature increases
Industrial cooling heats water
Removing streamside cover raises water temperature
Water that is too cold also causes problems
Water at the bottom of reservoirs behind dams is colder
When water is released, downstream water temperatures drop suddenly, favoring cold-loving invasive fish

36. APES Lesson 73 - Fresh Water Polution and its Control & Wastewater and its Treatment
Thermal pollution
Water that is too warm causes problems
Warmer water holds less oxygen
Dissolved oxygen decreases as temperature increases
Industrial cooling heats water
Removing streamside cover raises water temperature
Water that is too cold also causes problems
Water at the bottom of reservoirs behind dams is colder
When water is released, downstream water temperatures drop suddenly, killing aquatic organisms

37. Groundwater pollution is a difficult problem
Most pollution control efforts focus on surface water
Groundwater is increasingly contaminated but is hidden from view and difficult to monitor
“Out of sight, out of mind”
Groundwater pollution is harder to address than surface water pollution
Rivers flush pollutants out, but groundwater retains contaminants for decades and longer
It takes longer for contaminants to break down because of lower sunlight, microbes, and dissolved oxygen

38. Sources of groundwater pollution
APES Lesson 73 - Fresh Water Polution and its Control & Wastewater and its Treatment
Sources of groundwater pollution
Some toxic chemicals occur naturally
Aluminum, fluoride, sulfates
Pollution from human causes wastes leach through soils
Pathogens enter through improperly designed wells
Leaking underground storage and septic tanks

39. There are many sources of groundwater pollution
Some toxic chemicals occur naturally
Aluminum, fluoride, sulfates
Pollution from human causes is widespread
Industrial wastes can leach through soil
Pathogens enter through improperly designed wells
Leaking underground storage tanks are a source of carcinogenic pollutants from solvents and gasoline
EPA has confirmed leaks from 510,000 tanks and cleaned up 430,000 of them over the last 15 years

40. Groundwater pollution is a difficult problem
APES Lesson 73 - Fresh Water Polution and its Control & Wastewater and its Treatment
Groundwater pollution is a difficult problem
Groundwater is increasingly contaminated
But is hidden from view and difficult to monitor
“Out of sight, out of mind”
Groundwater pollution is hard to address
It retains contaminants for decades and longer
It takes longer for contaminants to break down because of lower sunlight, microbes, and dissolved oxygen
So far, the EPA has cleaned up 388,000 leaking tanks

41. There are many sources of groundwater pollution
Leaking radioactive waste also pollutes groundwater
In 2013, officials revealed that five underground storage tanks at the Hanford Nuclear Reservation in Washington were leaking radioactive waste
Billions of dollars have been spent on remediation

42. There are many sources of groundwater pollution
Agricultural pollution comes from several sources
Pesticides are in most of the shallow aquifers tested
Nitrates from fertilizers have caused cancer, miscarriages, and “blue-baby” syndrome
Pathogens such as Escherichia coli (E. coli) can cause illness

43. Agriculture and industry pollute groundwater
APES Lesson 73 - Fresh Water Polution and its Control & Wastewater and its Treatment
Agriculture and industry pollute groundwater
Agricultural pollution comes from several sources
Pesticides are in most of the shallow aquifers tested
Nitrates from fertilizers have caused cancer, miscarriages, and “blue-baby” syndrome
Pathogens like Escherichia coli (E. coli)
Manufacturing industries and military sites have been heavy polluters
By-products seep into water from miles around
Radioactive wastes will contaminate water for 750,000 years

44. Legislative efforts reduce pollution
APES Lesson 73 - Fresh Water Polution and its Control & Wastewater and its Treatment
Legislative efforts reduce pollution
Water pollution was worse decades ago
Citizen activism and government response resulted in legislation during the 1960s and 1970s
The situation is much better now
The Federal Water Pollution Control Act (1972)
Renamed the Clean Water Act in 1977
It is illegal to discharge pollution without a permit
Sets standards for industrial wastewater
Funded sewage treatment plants

45. Legislative and regulatory efforts have helped to reduce pollution
Water pollution was worse decades ago
Citizen activism and government response resulted in legislation during the 1960s and 1970s
Rivers and lakes are cleaner now
The Federal Water Pollution Control Act (1972)
Renamed as the Clean Water Act in 1977
Made it illegal to discharge pollution without a permit
Set standards for industrial wastewater
Funded sewage treatment plants

46. Legislative and regulatory efforts have helped to reduce pollution
Underfunded and understaffed state and federal regulatory agencies succumbed to pressure by industries and politicians who received money from them
Violations of the Clean Water Act have risen to over 100,000 documented violations/year
10% of Americans are unknowingly exposed to unsafe drinking water
Government action was taken to help the Great Lakes
The water quality of the lakes has dramatically improved
Recent Supreme Court decisions removed enforcement powers of the EPA over many waterways