WATER Chapter 11
WHERE DOES WATER COME FROM?
THERE ARE 2 KINDS OF WATER ON EARTH…
Fresh Water: contains little salt (you don’t notice it) Salt water: has a higher concentration of dissolved salt (think, ocean water)
THE WATER CYCLE Earth is the water planet Water exists in all forms: liquid, gas, solid Water is a renewable resources since it is circulated in the water cycle
THE WATER CYCLE
Evaporation: water evaporates from Earth’s surface and leaves behind salts and other impurities. Water vapor (gas) rises into the atmosphere
THE WATER CYCLE Condensation: as vapor rises, it cools and condenses into drops of liquid water that form clouds.
THE WATER CYCLE
Precipitation: water in clouds falls to Earth and replenishes the fresh water. Most of this water ends up in the oceans
WHY IS FRESH WATER A LIMITED RESOURCE? How much of the Earth is covered in water?
WHY IS FRESH WATER A LIMITED RESOURCE? 71% of Earth is covered in water, but 97% of that water is saltwater. That leaves only 3% as freshwater Of that 3%, 77% is frozen in glaciers and polar icecaps Only 23% is accessible ground water
SURFACE WATER Fresh water on Earth’s land surface Lakes, rivers, streams, wetlands Most large cities depend on surface water Used for drinking water, water to grow crops, food (shellfish, fish), hydropower, boat transportation
SURFACE WATER River systems Network of flowing water Water from precipitation flows downhill and combines with streams and larger rivers As these streams and rivers connect they form a system Watersheds The area of land that is drained by a river When precipitation falls in this area, it will flow into the same river system
Amazon River System and Watershed
Mississippi River System and Watershed
GROUNDWATER This is the majority of fresh water available for human use There is 20 times as much groundwater as surface water Water stored beneath Earth’s surface in sediments and in rock formations Water table: the level below the surface where the sediment is saturated with water In wet regions: water table is high Dry regions: water table is really low
GROUNDWATER Aquifer: an underground formation that contains groundwater Rocks, sand, gravel have lots of space in between each piece underground. Water fills in those spaces Water can also dissolve softer rock formations, creating caves; water can fill in those caves
GROUNDWATER To describe these rock formations that can store water we need to understand… Porosity- the amount of space between particles that make up rock Permeability- the ability of rock or soil to allow water to flow through
GROUNDWATER (PG. 274) For water to fill an aquifer it has to pass through permeable layers of soil and rock Recharge Zone- areas of Earth where water can percolate down into the aquifer These areas are environmentally sensitive (pollution here can affect the entire aquifer) The permeability of the ground can be affected by building and pavement It can take tens of thousands of years to refill an aquifer
GROUNDWATER (PG. 274) Well- a hole dug or drilled to reach groundwater Water is naturally filtered and purified as it travels underground Has to be dug deep enough to reach the water table If the groundwater is removed faster than it is recharged then the well may not be deep enough
LAB: MODELING A WATERSHED
WATER USE AND MANAGEMENT
“WE ALL LIVE DOWNSTREAM” Water pollution affects everyone The number of people who depend on Earth’s limited fresh water increases everyday (think back to populations) The World Health Organization estimates that more than 1 Billion people don’t have access to clean, reliable water source
GLOBAL WATER USE Water is used for 3 main categories: residential, agricultural, industrial Patterns of water use varies from region to region and depends on economic conditions, population size, and availability of water
RESIDENTIAL WATER USE Water for cooking, drinking, cleaning, toilets, washing cars, watering lawns. U.S. residents average about 300L (80 gal) per day India residents average about 41L (11 gal) per day
WATER TREATMENT Potable water = water that is safe to drink Water treatment removes Mercury Arsenic Lead Pathogens (organisms that cause illness) like bacteria, viruses, parasitic worms (these are introduced by sewage or animal feces)
WATER TREATMENT Usually includes both physical treatment and chemical treatment
Physical treatment filtering out large organisms and trash Using bacteria to consume impurities Second filtration to filter out smaller impurities Chemical treatment Chlorine to kill bacteria Air is added to improve taste and reduce odor Fluoride added to prevent tooth decay
INDUSTRIAL WATER USE 19% of global water use is industrial Manufacture goods (textiles) Dispose of waste Generate power It takes 500,000L (132,100 gal) water to manufacture a car Computer chips, semiconductors require lots of water Most of the water used in industry is used in power plant cooling systems
AGRICULTURAL WATER USE It takes 300 L (80 gal) water to produce 1 ear of corn Agriculture accounts for 67% of global water use and includes production of both plants and animals Irrigation is the process of providing water to plants from sources besides precipitation Plants require a lot of water and it needs to get to the roots 80 of water from irrigation evaporates
METHODS OF IRRIGATION
WATER MANAGEMENT
People have been changing rivers and streams for thousands of years Romans built aqueducts People in dry areas (Egypt, France) dug canals to bring water from rivers and mountains to dry areas Water management projects: Building dams Water diversion canals reservoirs Used to provide drinking water, water for agriculture and hydropower
WATER DIVERSION PROJECTS Owens River in CA diverted 300 km (186 mi) across mountains and desert Provides water for the LA area which is located in desert
DAMS AND RESERVOIRS A dam is a structure built across a river to control the flow of the river A reservoir is the artificial lake that forms behind the dam where
HOOVER DAM
PROS/CONS WITH DAMS (PG. 280) Pros
Cons
WATER CONSERVATION As water sources are depleted, water gets more expensive Wells need to be deeper, canals longer, polluted water needs to be cleaned Conservation of water ensures that everyone can have enough, cheap water Create a list of ways to conserve water in agriculture, industry and at home using pg. 281282 in your books
SOLUTIONS Conservation may not be enough especially in really dry areas or where populations are growing There are 2 possible solutions Desalination Transporting water
DESALINATION
Removing salt from water Problems?
TRANSPORTING WATER Bringing water into dry areas from other regions More than half of the US fresh water supply is in Alaska Scientists are considering pumping water from Alaskan rivers into giant plastic bags These bags will be towed on barges down to CA Problems?
BOTTLED WATER V. TAP
WATER POLLUTION Any chemical, physical, or biological agents that do not belong in water Sometimes you can’t tell that water is polluted (think of bacteria or viruses) All the ways we use water introduces pollution Industrialization and population growth cause the biggest problems
POINT SOURCE POLLUTION Pollution that comes from a single source Factory Wastewater treatment plant Leaking oil tanker You can point to the source of pollution on a map
NONPOINT-SOURCE POLLUTION Comes from many sources which are difficult to identify These pollutants are carried into water sources in runoff from a rainstorm Chemicals added to road surfaces (salt, oil) Pesticides, herbicides, fertilizers from lawns, farmland Precipitation with air pollutants
WASTEWATER Water that contains waste from homes or industry This is the water that goes down the drain Wastewater goes through a series of sewage pipes to a wastewater treatment plant Treatment produces water that can return to a river or lake or potable water
TREATMEN 2 Phases of treatment: Primary and Secondary Treatment
TREATMEN
Primary Treatment: Step 1: Filtration, wastewater passes through a large screen to remove solid objects
TREATMEN Primary Treatment: Step 2: Settling tank, wastewater sits in a large tank where small particles sink to the bottom (sewer sludge)
TREATMEN Secondary Treatment: Step 3: Second filtration, wastewater goes to a large tank where any sludge is removed
TREATMEN
Secondary Treatment: Step 4: Aeration tank, wastewater is mixed with oxygen and bacteria which feed on the wastes
TREATMEN
Secondary Treatment: Step 5: Chlorination, chlorine is added to disinfect water
WHAT HAPPENS TO THAT SEWER SLUDGE? Sludge is the solid material that remains after treatment (there’s a lot of it) If it contains toxic chemicals it must be disposed of as hazardous waste
Often it is incinerated or put in a landfill Industries are looking for other uses for nontoxic sludge like fertilizer or making bricks
THE POOP TRAIN Listen carefully to this story about NYC’s sludge and answer the questions on your worksheet
EUTROPHICATION Aquatic ecosystems require nutrients just like any terrestrial ecosystem These nutrients are produced by decaying leaves or bacteria in the aquatic ecosystem Too much of these nutrients causes eutrophication Nutrients decay, decay uses up oxygen, decreasing oxygen levels affect the organisms that can live in that ecosystem This is a natural process that produces marshes
ARTIFICIAL EUTROPHICATION
In artificial eutrophication, this process is accelerated when nutrients from sewage and fertilizers enter the water Mostly from farms, gardens, and lawns High levels of phosphorus cause algal blooms that use up all the oxygen which suffocates fish
THERMAL POLLUTION A temperature increase in a body of water that is caused by human activity Leads to decreases in oxygen in the water Power plants use water in their cooling systems and release it into nearby lakes and streams
GROUNDWATER POLLUTION Usually occurs when surface water is polluted and then enters the groundwater Underground storage tanks for petroleum (gas stations, homes) can also cause groundwater pollution Groundwater pollution is difficult to clean up because it is difficult to access and is spread out so far Check out the figure on page 290 and see how many sources of groundwater pollution you can find
OCEAN POLLUTION Oceans are huge, but still vulnerable to pollution 85% of ocean pollution comes from activities on land Oil spills are a huge source of ocean pollution 37 million gallons are spilled from tanker ship accidents 250 million gallons enter the ocean from cities and towns
HOW DOES WATER POLLUTION AFFECT ECOSYSTEMS? Pollutants can have an immediate effect on ecosystems (toxins killing populations immediately) Biomagnification is a more common issue This is the buildup of pollutants as you go up the food chain in an ecosystem This happens because many pollutants do not decay quickly
BIOMAGNIFICATION
LAWS TO IMPROVE WATER QUALITY Read the “Cleaning Up Water Pollution” section on pages 292-293. You have been assigned one of the laws in the table on pg. 293. In your groups, you must answer the following questions 1. Explain the purpose of this law.
2. When did this law go into effect? 3. What types of water sources does this protect? 4. What types of pollution would this law prevent? 5. Who benefits from this law?
AIR AND ATMOSPHERE Chapters 12 and 13
AIR POLLUTION AND CIGARETTE SMOKE
Clean air is primarily nitrogen and oxygen gas with small amounts or argon, carbon dioxide and water vapor Air pollution: harmful substances built up in the air to unhealthy levels Comes from natural AND human sources
PRIMARY POLLUTANT Pollution put directly into the air by human activities Soot from smoke Carbon monoxide
Use table 1 on page 304 to fill in your table of primary air pollutants
SECONDARY POLLUTANT Created when primary pollutants come in contact with other primary air pollutants or with naturally occurring substances (water vapor) and a chemical reaction takes place Ground-level ozone: vehicle emissions react with ultra-violet sunlight and mix with oxygen in the atmosphere Acid rain
MOTOR VEHICLE EMISSIONS What types of primary air pollutants come from vehicles? How do we solve this problem?
AIR POLLUTION AND MOTOR VEHICLES Over 1/3 of air pollution comes from gasoline burned in motor vehicles 70% cars and trucks 30% commercial vehicles Clean Air Act (1970, 1990) – regulates emission from automobiles Gradual elimination of lead from gasoline Catalytic converters to clean exhaust gases before exiting tailpipes
INDUSTRIAL AIR POLLUTION Electric power plants produce 2/3 of all SO2 1/3 of all NOx 1/3 of particulate matter
SCRUBBERS Required for many industries by Clean Air Act to remove some pollutants before discharge into atmosphere
Electrostatic precipitators remove 22 million tons of ash generated by coalburning power plants each year
THERMAL INVERSIONS • Normally, air temperature decreases with height and allows pollutants to escape from Earth’s atmosphere
THERMAL INVERSIONS In a thermal inversion, the air above is warmer than the air below. This traps pollutants near the Earth’s surface
THERMAL INVERSIONS Consequences: Freezing rain Intense thunderstorms and tornadoes Smog London, 1952
Other cities Los Angeles, Mexico City, Mexico, Mumbai, India, Santiago, Chile, Tehran, Iran
Lo
London, 1952 ↑ Mexico City, 2009 ↓
Los Angeles ↑ Beijing, 2008 ↓
FORMATION OF SMOG Air pollution hangs over urban areas and reduces visibility CAMNET http://www.hazecam.net /camsite.aspx?site=newa rk
HEALTH EFFECTS OF SMOG Most susceptible – young children, elderly and those with chronic lung conditions
CHRONIC BRONCHITIS Mucus membranes become inflamed, irritated and swell Airways narrow, causing coughing and breathlessness May damage cilia that are responsible for brushing out debris, irritants and mucus
EMPHYSEMA Air sacs in lungs lose their elasticity and can no longer expel air from lungs Carbon dioxide and oxygen exchange is impaired
LUNG CANCER 78% of lung cancer is attributed to smoking Air pollution may increase the risk of lung cancer Other agents: Beryllium, asbestos, vinyl chloride, nickel chromates, coal products, gasoline, diesel exhaust, arsenic and radon
INDOOR AIR POLLUTION Americans spend 89% of their time indoors Air pollution can be worse inside a building Sources include plastics and industrial compounds Carpets, building materials, paints, upholstery, furniture
SICK BUILDING SYNDROME Windows are tightly sealed, preventing pollutants from circulating and passing out of building Pollutants accumulate and reach dangerously high levels Common in Southern California, desert Southwest and Florida
POLK COUNTY COURTHOUSE, BARTOW, FL
Commercial name given to 6 naturally occurring minerals that contain silica Fibers were used for their strength, flexibility, and heat, chemical and thermal resistance
ASBESTOS Used to reinforce cement, remake brake linings, vinyl floors, residential siding, insulation and protect firefighters Used extensively in commercial buildings
US has spent $40 billion clean up schools
RADON Naturally occurring radioactive element, produced by decay of uranium (found in the Earth) Most concentrated in porous soils overlying rocks that contain uranium Odorless, tasteless, invisible gas that can adhere to dust particles
RADON When inhaled, radon releases alpha particles that can destroy DNA in lung cells and can lead to cancer (2nd leading cause)
NOISE AND LIGHT POLLUTION Affects human health and quality of life and natural ecosystems Where would noise and light pollution be a problem?
ACID PRECIPITATION Rain, sleet, or snow with high concentration of acids Burned fossil fuels release sulfur oxides and nitrogen oxides, these combine with water in the atmosphere and form acid precipitation.
EFFECTS OF ACID RAIN dissolves stone and metals Harm plant and aquatic life Irritate respiratory tract and eyes Aggravates asthma and chronic bronchitis