Presentation on theme: "Solid and Hazardous Waste"— Presentation transcript:
1Solid and Hazardous Waste Chapter 22Solid and Hazardous Waste
2Chapter Overview Questions What is solid waste and how much do we produce?How can we produce less solid waste?What are the advantages and disadvantages of reusing recycled materials?What are the advantages and disadvantages of burning or burying solid waste?What is hazardous waste and how can we deal with it?
3Chapter Overview Questions (cont’d) What can we do to reduce exposure to lead and mercury?How can we make the transition to a more sustainable low-waste society?
4Core Case Study: Love Canal — There Is No “Away” Between , Hooker Chemical sealed multiple chemical wastes into steel drums and dumped them into an old canal excavation (Love Canal).In 1953, the canal was filled and sold to Niagara Falls school board for $1.The company inserted a disclaimer denying liability for the wastes.
5Core Case Study: Love Canal — There Is No “Away” In 1957, Hooker Chemical warned the school not to disturb the site because of the toxic waste.In 1959 an elementary school, playing fields and homes were built disrupting the clay cap covering the wastes.In 1976, residents complained of chemical smells and chemical burns from the site.
6Core Case Study: Love Canal — There Is No “Away” President Jimmy Carter declared Love Canal a federal disaster area.The area was abandoned in 1980 (left).Figure 22-1
7Core Case Study: Love Canal — There Is No “Away” It still is a controversy as to how much the chemicals at Love Canal injured or caused disease to the residents.Love Canal sparked creation of the Superfund law, which forced polluters to pay for cleaning up abandoned toxic waste dumps.
8WASTING RESOURCESSolid waste: any unwanted or discarded material we produce that is not a liquid or gas.Municipal solid waste (MSW): produce directly from homes.Industrial solid waste: produced indirectly by industries that supply people with goods and services.Hazardous (toxic) waste: threatens human health or the environment because it is toxic, chemically active, corrosive or flammable.
9WASTING RESOURCESSolid wastes polluting a river in Jakarta, Indonesia. The man in the boat is looking for items to salvage or sell.Figure 22-3
10WASTING RESOURCESThe United States produces about a third of the world’s solid waste and buries more than half of it in landfills.About 98.5% is industrial solid waste.The remaining 1.5% is MSW.About 55% of U.S. MSW is dumped into landfills, 30% is recycled or composted, and 15% is burned in incinerators.
12Electronic Waste: A Growing Problem E-waste consists of toxic and hazardous waste such as PVC, lead, mercury, and cadmium.The U.S. produces almost half of the world's e-waste but only recycles about 10% of it.Figure 22-4
13INTEGRATED WASTE MANAGEMENT We can manage the solid wastes we produce and reduce or prevent their production.Figure 22-5
14First Priority Second Priority Last Priority Primary Pollution and Waste PreventionSecondary Pollutionand Waste PreventionWaste Management• Treat waste to reducetoxicity• Change industrialprocess to eliminateuse of harmfulchemicals• Reuse products• Repair products• Incinerate waste• Recycle• Bury waste inlandfills• Purchase differentproducts• Compost• Release waste intoenvironment fordispersal or dilution• Buy reusablerecyclable products• Use less of a harmfulproduct• Reduce packagingand materials inproductsFigure 22.5Integrated waste management: priorities suggested by prominent scientists for dealing with solid waste. To date, these waste-reduction priorities have not been followed in the United States and in most other countries. Instead, most efforts are devoted to waste management (bury it or burn it). QUESTION: Why do most countries not follow these priorities based on sound science? (Data from U.S. Environmental Protection Agency and U.S. National Academy of Sciences)• Make products thatlast longer and arerecyclable, reusable,or easy to repairFig. 22-5, p. 523
15Solutions: Reducing Solid Waste Refuse: to buy items that we really don’t need.Reduce: consume less and live a simpler and less stressful life by practicing simplicity.Reuse: rely more on items that can be used over and over.Repurpose: use something for another purpose instead of throwing it away.Recycle: paper, glass, cans, plastics…and buy items made from recycled materials.
16What Can You Do? Solid Waste • Follow the five Rs of resource use: Refuse, Reduce,Reuse, Repurpose, and Recycle.• Ask yourself whether you really need a particular item.• Rent, borrow, or barter goods and services when you can.• Buy things that are reusable, recyclable, or compostable, and be sure to reuse, recycle, and compost them.• Do not use throwaway paper and plastic plates,cups and eating utensils, and other disposable itemswhen reusable or refillable versions are available.Figure 22.6Individuals matter: ways to save resources and reduce your output of solid waste and pollution. QUESTIONS: Which three of these actions do you think are the most important? Which ones do you do?• Refill and reuse a bottled water container with tap water.• Use in place of conventional paper mail.• Read newspapers and magazines online.• Buy products in concentrated form whenever possible.Fig. 22-6, p. 524
17REUSEReusing products is an important way to reduce resource use, waste, and pollution in developed countries.Reusing can be hazardous in developing countries for poor who scavenge in open dumps.They can be exposed to toxins or infectious diseases.
18How People Reuse Materials Children looking for materials to sell in an open dump near Manila in the Philippines.Figure 22-2
19Case Study: Using Refillable Containers Refilling and reusing containers uses fewer resources and less energy, produces less waste, saves money, and creates jobs.In Denmark and Canada’s Price Edward’s Island there is a ban on all beverage containers that cannot be reused.In Finland 95% of soft drink and alcoholic beverages are refillable (Germany 75%).
20REUSEReducing resource waste: energy consumption for different types of 350-ml (12-oz) beverage containers.Figure 22-7
21Glass drink bottle, used once Aluminum can, used onceSteel can, used onceRecycled steel canGlass drink bottle, used onceRecycled aluminum canRecycled glass drink bottleFigure 22.7Reducing resource waste: energy consumption for different types of 350-milliliter (12-fluid ounce) beverage containers. (Data from Argonne National Laboratory)Refillable drink bottle, used 10 timesEnergy (thousands of kilocalories)Fig. 22-7, p. 525
22How Would You Vote?Do you support banning all beverage containers that cannot be reused as Denmark has done?a. No. Reused containers may be unsanitary.b. Yes. A ban will save energy, money, and resources and result in a cleaner environment.
23Solutions: Other Ways to Reuse Things We can use reusable shopping bags, food containers, and shipping pallets, and borrow tools from tool libraries.Many countries in Europe and Asia charge shoppers for plastic bags.
24How Would You Vote?Should consumers have to pay for plastic or paper bags at grocery and other stores?a. No. Instead, give discounts to people who bring their own bags.b. Yes. Making consumers buy their bags will reduce waste.
25• Buy beverages in refillable glass containers What Can You Do?Reuse• Buy beverages in refillable glass containersinstead of cans or throwaway bottles.• Use reusable plastic or metal lunchboxes.• Carry sandwiches and store food in the refrigerator in reusable containers instead of wrapping them in aluminum foil or plastic wrap• Use rechargeable batteries and recycle themwhen their useful life is over.• Carry groceries and other items in a reusablebasket, a canvas or string bag, or a small cart.Figure 22.8Individuals matter: ways to reuse some of the items you buy. QUESTIONS: Which three of these actions do you think are the most important? Which ones do you do?• Use reusable sponges and washable clothnapkins, dishtowels, and handkerchiefsinstead of throwaway paper ones.• Buy used furniture, computers, cars, and other items.• Give or sell items you no longer use to others.Fig. 22-8, p. 526
26RECYCLINGPrimary (closed loop) recycling: materials are turned into new products of the same type.Secondary recycling: materials are converted into different products.Used tires shredded and converted into rubberized road surface.Newspapers transformed into cellulose insulation.
27RECYCLINGThere is a disagreement over whether to mix urban wastes and send them to centralized resource recovery plants or to sort recyclables for collection and sale to manufacturers as raw materials.To promote separation of wastes, 4,000 communities in the U.S. have implemented pay-as-you-throw or fee-per-bag waste collection systems.
28How Would You Vote?Should households and businesses be charged for the amount of mixed waste picked up but not charged for pickup of materials separated for recycling?a. No. It would encourage illegal dumping and burning of wastes.b. Yes. Consumer source separation saves money and makes consumers more conscientious.
29RECYCLINGComposting biodegradable organic waste mimics nature by recycling plant nutrients to the soil.Recycling paper has a number of environmental (reduction in pollution and deforestation, less energy expenditure) and economic benefits and is easy to do.
30RECYCLINGRecycling many plastics is chemically and economically difficult.Many plastics are hard to isolate from other wastes.Recovering individual plastic resins does not yield much material.The cost of virgin plastic resins in low than recycled resins due to low fossil fuel costs.There are new technologies that are making plastics biodegradable.
31How Would You Vote?Should we place much greater emphasis on recycling with the goal of recycling at least 60% of the municipal solid waste that we produce?a. No. Recycling programs should be market driven rather than setting unrealistically high goals that will either fail or require support from already overtaxed citizens.b. Yes. High recycling rates will reduce pollution and save energy.
32RECYCLINGReuse and recycling are hindered by prices of goods that do not reflect their harmful environmental impacts, too few government subsidies and tax breaks, and price fluctuations.
33How Would You Vote?Should governments pass laws requiring manufacturers to take back and reuse or recycle all packaging waste, appliances, electronic equipment, and motor vehicles at the end of their useful lives?a. No. These regulations would increase prices for consumers.b. Yes. The regulations would promote the manufacturing of more environmentally friendly products and further protect the environment.
34Trade-Offs Recycling Advantages Disadvantages Reduces air and water pollutionDoes not save landfill space in areas with ample landSaves energyReduces mineral demandMay lose money for items such as glass and most plasticReduces greenhouse gas emissionsReduces solid waste production and disposalReduces profits from landfills and incineratorsFigure 22.9Trade-offs: advantages and disadvantages of recycling solid waste. QUESTION: Which single advantage and which single disadvantage do you think are the most important?Helps protect biodiversityCan save money for items such as paper, metals, and some plasticsSource separation is inconvenient for some peopleImportant part of economyFig. 22-9, p. 529
35BURNING AND BURYING SOLID WASTE Globally, MSW is burned in over 1,000 large waste-to-energy incinerators, which boil water to make steam for heating water, or space, or for production of electricity.Japan and a few European countries incinerate most of their MSW.
36Burning Solid WasteWaste-to-energy incinerator with pollution controls that burns mixed solid waste.Figure 22-10
37Wet scrubber Waste pit Bottom ash ElectricitySmokestackTurbineSteamCraneGeneratorWetscrubberFurnaceBoilerElectrostaticprecipitatorWastepitFigure 22.10Solutions: this waste-to-energy incinerator with pollution controls that burns mixed solid waste and recovers some of the energy to produce steam used for heating or producing electricity.WateraddedBottomashDirtywaterConveyorFly ashConventionallandfillWastetreatmentHazardouswaste landfillFig , p. 530
38Trade-Offs Incineration Advantages Disadvantages Expensive to build Reduces trash volumeExpensive to buildCosts more thanshort-distancehauling tolandfillsLess needfor landfillsLow water pollutionDifficult to site because of citizen oppositionConcentrates hazardous substancesinto ash forburial or useas landfillcoverSome air pollutionOlder or poorly managed facilities can release large amounts of air pollutionFigure 22.11Trade-offs: advantages and disadvantages of waste-to-energy incineration of solid waste. These trade-offs also apply to the incineration of hazardous waste. QUESTION: Which single advantage and which single disadvantage do you think are the most important?Output approach that encourages waste productionSale of energy reduces costModern controls reduce air pollutionCan compete with recycling for burnable materials such as newspaperSome facilities recover and sell metalsFig , p. 531
39How Would You Vote?Do the advantages of incinerating solid waste outweigh the disadvantages?a. Yes. Incineration is a sanitary and effective method for eliminating infectious and organic wastes.b. No. Incineration can generate toxic air pollution and ashes.
40Burying Solid WasteMost of the world’s MSW is buried in landfills that eventually are expected to leak toxic liquids into the soil and underlying aquifers.Open dumps: are fields or holes in the ground where garbage is deposited and sometimes covered with soil. Mostly used in developing countries.Sanitary landfills: solid wastes are spread out in thin layers, compacted and covered daily with a fresh layer of clay or plastic foam.
41Pipes collect explosive methane as used as fuel When landfill is full,layers of soil and clayseal in trashTopsoilElectricitygeneratorbuildingSandClayMethane storageand compressorbuildingLeachatetreatment systemGarbageProbes todetectmethaneleaksPipes collect explosive methane as used as fuelto generate electricityMethane gasrecovery wellLeachatestoragetankCompactedsolid wasteFigure 22.12Solutions: state-of-the-art sanitary landfill, which is designed to eliminate or minimize environmental problems that plague older landfills. Even these landfills are expected to leak eventually, passing both the effects of contamination and cleanup costs on to future generations. Since 1997, only modern sanitary landfills are allowed in the United States. As a result, many older and small landfills have been closed and replaced with larger local and regional modern landfills.GarbageGroundwatermonitoringwellLeachatepipesLeachate pumpedup to storage tankfor safe disposalSandSyntheticlinerLeachatemonitoringwellSandClay and plastic liningto prevent leaks; pipescollect leachate frombottom of landfillGroundwaterClaySubsoilFig , p. 532
42Trade-Offs Sanitary Landfills Advantages Disadvantages Noise and trafficNo open burningDustLittle odorAir pollution from toxic gases and volatile organiccompoundsLow groundwaterpollution if sited properlyReleases greenhouse gases (methane and CO2)unless they are collectedCan be built quicklyLow operating costsGroundwater contaminationFigure 22.13Trade-offs: advantages and disadvantages of using sanitary landfills to dispose of solid waste. QUESTION: Which single advantage and which single disadvantage do you think are the most important?Can handle large amounts of wasteSlow decompositionof wastesFilled land can be used for other purposesDiscourages recycling, reuse, and waste reductionNo shortage of landfill space in many areasEventually leaks and can contaminate groundwaterFig , p. 533
43How Would You Vote?Do the advantages of burying solid waste in sanitary landfills outweigh the disadvantages?a. No. Ultimately, landfills leak and pollute the environment.b. Yes. They have relatively low operating costs, can store large amounts of waste, and are designed to prevent pollution.
44Case Study: What Should We Do with Used Tires? We face a dilemma in deciding what to so with hundreds of millions of discarded tires.Figure 22-14
45HAZARDOUS WASTEHazardous waste: is any discarded solid or liquid material that is toxic, ignitable, corrosive, or reactive enough to explode or release toxic fumes.The two largest classes of hazardous wastes are organic compounds (e.g. pesticides, PCBs, dioxins) and toxic heavy metals (e.g. lead, mercury, arsenic).
46What Harmful Chemicals Are in Your Home? CleaningGardening• Disinfectants• Pesticides• Drain, toilet, andwindow cleaners• Weed killers• Ant and rodent killers• Spot removers• Septic tank cleaners• Flea powdersPaint• Latex and oil-based paints• Paint thinners, solvents,and strippersAutomotive• Stains, varnishes,and lacquersFigure 22.15Science: harmful chemicals found in many U.S. homes. The U.S. Congress has exempted disposal of these materials from government regulation. QUESTION: Which of these chemicals are in your home?• Gasoline• Wood preservatives• Used motor oil• Antifreeze• Artist paints and inks• Battery acidGeneral• Solvents• Dry-cell batteries(mercury and cadmium)• Brake andtransmission fluid• Glues and cements• Rust inhibitor andrust removerFig , p. 534
47Hazardous Waste Regulations in the United States Two major federal laws regulate the management and disposal of hazardous waste in the U.S.:Resource Conservation and Recovery Act (RCRA)Cradle-to-the-grave system to keep track waste.Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)Commonly known as Superfund program.
48Hazardous Waste Regulations in the United States The Superfund law was designed to have polluters pay for cleaning up abandoned hazardous waste sites.Only 70% of the cleanup costs have come from the polluters, the rest comes from a trust fund financed until 1995 by taxes on chemical raw materials and oil.
49How Would You Vote?Should the U.S. Congress reinstate the polluter-pays principle by using taxes from chemical, oil, mining, and smelting companies to reestablish a fund for cleaning up existing and new Superfund sites?a. No. All taxpayers, not certain industries, should pay for cleaning up sites polluted in the past.b. Yes. Funding for Superfund is needed and waste-generating industries rather than ordinary citizens should fund it.
50DEALING WITH HAZARDOUS WASTE We can produce less hazardous waste and recycle, reuse, detoxify, burn, and bury what we continue to produce.Figure 22-16
51Convert to Less Hazardous or Nonhazardous Substances Produce Less WasteManipulateprocessesto eliminateor reduceproductionRecycleandreuseConvert to Less Hazardous or Nonhazardous SubstancesChemical,physical, andbiologicaltreatmentOcean andatmosphericassimilationLandtreatmentThermaltreatmentIncinerationFigure 22.16Integrated hazardous waste management: priorities suggested by prominent scientists for dealing with hazardous waste. To date, these priorities have not been followed in the United States and in most other countries. (Data from U.S. National Academy of Sciences)Put in Perpetual StorageArid regionunsaturatedzoneWastepilesSurfaceimpoundmentsSaltformationsUndergroundinjectionLandfillFig , p. 536
52Conversion to Less Hazardous Substances Physical Methods: using charcoal or resins to separate out harmful chemicals.Chemical Methods: using chemical reactions that can convert hazardous chemicals to less harmful or harmless chemicals.
53Conversion to Less Hazardous Substances Biological Methods:Bioremediation: bacteria or enzymes help destroy toxic and hazardous waste or convert them to more benign substances.Phytoremediation: involves using natural or genetically engineered plants to absorb, filter and remove contaminants from polluted soil and water.
54Radioactive contaminants Organic contaminants Inorganic metal contaminantsPoplar treeBrake fernSunflowerWillow treeIndian mustardLandfillPollutedgroundwater inOilspillFigure 22.17Solutions: phytoremediation. Various types of plants can be used as pollution sponges to clean up soil and water and radioactive substances (left), organic compounds (center), and toxic metals (right). (Data from American Society of Plant Physiologists, U.S. Environmental Protection Agency, and Edenspace)PollutedleachateDecontaminatedwater outSoilSoilGroundwaterGroundwaterRhizofiltrationRoots of plants such assunflowers with danglingroots on ponds or in green-houses can absorb pollutantssuch as radioactive strontium-90 and cesium-137 and variousorganic chemicals.PhytostabilizationPlants such as willow trees and poplars can absorb chemicals and keep them from reaching groundwater or nearby surface water.PhytodegradationPlants such as poplarscan absorb toxic organicchemicals and break them down into less harmful compounds which they store orrelease slowly into the air.PhytoextractionRoots of plants such as Indianmustard and brake ferns canabsorb toxic metals such aslead, arsenic, and others andstore them in their leaves.Plants can then be recycledor harvested and incinerated.
55Can reduce material dumped into landfills Trade-OffsPhytoremediationAdvantagesDisadvantagesEasy to establishSlow (cantake severalgrowingseasons)InexpensiveEffective onlyat depth plantroots canreachCan reduce material dumped into landfillsSome toxic organic chemicals may evaporate from plant leavesFigure 22.18Trade-offs: advantages and disadvantages of using phytoremediation to remove or detoxify hazardous waste. QUESTION: Which single advantage and which single disadvantage do you think are the most important?Produces little air pollution compared to incinerationSome plantscan becometoxic toanimalsLow energy useFig , p. 538
56How Would You Vote?Do the advantages of using phytoremediation to detoxify hazardous waste outweigh the disadvantages?a. No. The process is often too slow and cannot remove contaminants below the root zones of the remediating plants.b. Yes. Plants can be effective in removing organics, radionuclides, and inorganic contaminants from soil and water.
57Conversion to Less Hazardous Substances Incineration: heating many types of hazardous waste to high temperatures – up to 2000 °C – in an incinerator can break them down and convert them to less harmful or harmless chemicals.
58Conversion to Less Hazardous Substances Plasma Torch: passing electrical current through gas to generate an electric arc and very high temperatures can create plasma.The plasma process can be carried out in a torch which can decompose liquid or solid hazardous organic material.
59Mobile. Easy to move to different sites Trade-OffsPlasma ArcAdvantagesDisadvantagesSmallHigh costProduces CO2 and COMobile. Easy to move to different sitesCan release particulates and chlorine gasFigure 22.19Trade-offs: advantages and disadvantages of using a plasma arc torch to detoxify hazardous wastes. QUESTION: Which single advantage and which single disadvantage do you think are the most important?Can vaporize and release toxic metals and radioactive elementsProduces notoxic ashFig , p. 538
60How Would You Vote?Do the advantages of using a plasma torch to detoxify hazardous waste outweigh the disadvantages?a. No. Plasma torches are expensive and the combustion byproducts may be harmful to the environment and humans.b. Yes. Plasma torches are convenient for disposing of hazardous wastes.
61Long-Term Storage of Hazardous Waste Hazardous waste can be disposed of on or underneath the earth’s surface, but without proper design and care this can pollute the air and water.Deep-well disposal: liquid hazardous wastes are pumped under pressure into dry porous rock far beneath aquifers.Surface impoundments: excavated depressions such as ponds, pits, or lagoons into which liners are placed and liquid hazardous wastes are stored.
62Deep Underground Wells Trade-OffsDeep Underground WellsAdvantagesDisadvantagesSafe method ifsites are chosencarefullyLeaks or spills atsurfaceLeaks fromcorrosion of wellcasingWastes can beretrieved ifproblemsdevelopExisting fracturesor earthquakescan allow wastesto escape intogroundwaterFigure 22.20Trade-offs: advantages and disadvantages of injecting liquid hazardous wastes into deep underground wells. QUESTION: Which single advantage and which single disadvantage do you think are the most important?Easy to doEncourageswaste productionLow costFig , p. 539
63How Would You Vote?Do the advantages of deep-well disposal of hazardous waste outweigh the disadvantages?a. No. The systems may leak and contaminate valuable soils, sediments, and groundwaters.b. Yes. Deep injection wells can be designed to permanently remove hazardous wastes from surface and near-surface environments.
64Low construction costs Trade-OffsSurface ImpoundmentsAdvantagesDisadvantagesGroundwatercontaminationfrom leaking liners(or no lining)Low construction costsLow operating costsAir pollution fromvolatile organiccompoundsCan be built quicklyOverflow fromfloodingFigure 22.21Trade-offs: advantages and disadvantages of storing liquid hazardous wastes in surface impoundments. QUESTION: Which single advantage and which single disadvantage do you think are the most important?Wastes can be retrieved if necessaryDisruption andleakage fromearthquakesCan store wastes indefinitely with secure double linersPromotes wasteproductionFig , p. 539
65How Would You Vote?Do the advantages of storing hazardous wastes in surface impoundments outweigh the disadvantages?a. No. The environment should not be openly exposed to liquid hazardous wastes.b. Yes. Surface impoundments are inexpensive solutions for at least the temporary storage of liquid wastes.
66Long-Term Storage of Hazardous Waste Long-Term Retrievable Storage: Some highly toxic materials cannot be detoxified or destroyed. Metal drums are used to stored them in areas that can be inspected and retrieved.Secure Landfills: Sometimes hazardous waste are put into drums and buried in carefully designed and monitored sites.
67Secure Hazardous Waste Landfill In the U.S. there are only 23 commercial hazardous waste landfills.Figure 22-22
68Bulk waste Gas vent Topsoil Plastic cover Earth Impervious clay cap SandClaycapImperviousclayWatertableFigure 22.22Solutions: secure hazardous waste landfill.EarthLeakdetectionsystemGroundwaterPlasticdoublelinerDouble leachatecollection systemReactivewastesin drumsGroundwatermonitoringwellFig , p. 540
69• Use pesticides in the smallest amount possible. What Can You Do?Hazardous Waste• Use pesticides in the smallest amount possible.• Use less harmful substances instead of commercial chemicals for most household cleaners. For example use liquid ammonia to clean appliances and windows; vinegar to polish metals, clean surfaces, and remove stains and mildew; baking soda to clean household utensils, deodorize, and remove stains; borax toremove stains and mildew.Figure 22.23Individuals matter: ways to reduce your input of hazardous waste into the environment. QUESTION: Which two things in this list do you do or plan to do?• Do not dispose of pesticides, paints, solvents, oil, antifreeze, or other products containing hazardous chemicals by flushing them down the toilet, pouring them down the drain, burying them, throwing them into the garbage, or dumping them down storm drains.Fig , p. 540
70Case Study: LeadLead is especially harmful to children and is still used in leaded gasoline and household paints in about 100 countries.Figure 22-24
71Solutions Lead Poisoning Prevention Control Phase out leaded gasoline worldwideSharply reduce lead emissions from old and new incineratorsPhase out waste incinerationReplace lead pipes and plumbing fixtures containing lead solderTest blood for lead by age 1Remove leaded paint and lead dust from older houses and apartmentsBan use of lead solderRemove lead from TV sets and computer monitors before incineration or land disposalBan use of lead in computer and TV monitorsFigure 22.24Solutions: ways to help protect children from lead poisoning. QUESTION: Which two of these solutions do you think are the most important?Test for lead in existing ceramicware used to serve foodBan lead glazing for ceramicware used to serve foodTest existing candles for leadBan candles with lead coresWash fresh fruits and vegetablesFig , p. 541
72Case Study: MercuryMercury is released into the environment mostly by burning coal and incinerating wastes and can build to high levels in some types of fish.Figure 22-26
73Solutions Mercury Pollution Prevention Control Phase out waste incinerationSharply reduce mercury emissions from coal-burning plants and incineratorsRemove mercury from coal before it is burnedConvert coal to liquid or gaseous fuelTax each unit of mercury emitted by coal-burning plants and incineratorsSwitch from coal to natural gas and renewable energy resources such as wind, solar cells, and hydrogenCollect and recycle mercury-containing electric switches, relays, and dry-cell batteriesFigure 22.26Solutions: ways to prevent or control inputs of mercury into the environment from human activities—mostly through coal-burning plants and incinerators. QUESTION: Which four of these solutions do you believe are the most important?Phase out use of mercury in all products unless they are recycledRequire labels on all products containing mercuryFig , p. 543
74Fig. 22-25, p. 542 AIR WINDS PRECIPITATION WINDS PRECIPITATION Hg and SO2Hg2+ and acidsHg2+ and acidsPhoto-chemicalHuman sourcesElementalmercuryvapor(Hg)Inorganic mercuryand acids(Hg2+)Inorganic mercuryand acids(Hg2+)Coal-burningplantIncineratorDepositionRunoff of Hg2+ and acidsDepositionWATERLarge fishVaporizationDepositionSmall fishBIOMAGNIFICATIONIN FOOD CHAINDepositionFigure 22.25Science: cycling of mercury in aquatic environments, in which mercury is converted from one form to another. The most toxic form to humans is methylmercury (CH3Hg+), which can be biologically magnified in aquatic food chains. Some mercury is also released back into the atmosphere as mercury vapor. QUESTION: What is your most likely exposure to mercury?PhytoplanktonZooplanktonBacteriaand acidsOxidationElementalmercury liquid(Hg)Inorganicmercury(Hg2+)Organicmercury(CH3Hg+)BacteriaSettlesoutSettlesoutSettlesoutSEDIMENTFig , p. 542
75ACHIEVING A LOW-WASTE SOCIETY In the U.S., citizens have kept large numbers of incinerators, landfills, and hazardous waste treatment plants from being built in their local areas.Environmental justice means that everyone is entitled to protection from environmental hazards without discrimination.
76Global Outlook: International Action to Reduce Hazardous Waste An international treaty calls for phasing out the use of harmful persistent organic pollutants (POPs).POPs are insoluble in water and soluble in fat.Nearly every person on earth has detectable levels of POPs in their blood.The U.S has not ratified this treaty.
77Making the Transition to a Low-Waste Society: A New Vision Everything is connected.There is no “away” for the wastes we produce.Dilution is not always the solution to pollution.The best and cheapest way to deal with wastes are reduction and pollution prevention.