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

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.

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.

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.

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.

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

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

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

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

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

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

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

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

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

Will we see a future of water wars?

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.

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”

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

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

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

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

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.

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

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)

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

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

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

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

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.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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