Solid and Hazardous Waste

Solid and Hazardous Waste
Chapter 22 Solid and Hazardous Waste

Chapter 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?

Chapter 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?

Core 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.

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.

President Jimmy Carter declared Love Canal a federal disaster area. The area was abandoned in 1980 (left). Figure 22-1

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.

WASTING RESOURCES Solid 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.

WASTING RESOURCES Solid wastes polluting a river in Jakarta, Indonesia. The man in the boat is looking for items to salvage or sell. Figure 22-3

WASTING RESOURCES The 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.

Electronic 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

INTEGRATED WASTE MANAGEMENT
We can manage the solid wastes we produce and reduce or prevent their production. Figure 22-5

First Priority Second Priority Last Priority Primary Pollution
and Waste Prevention Secondary Pollution and Waste Prevention Waste Management • Treat waste to reduce toxicity • Change industrial process to eliminate use of harmful chemicals • Reuse products • Repair products • Incinerate waste • Recycle • Bury waste in landfills • Purchase different products • Compost • Release waste into environment for dispersal or dilution • Buy reusable recyclable products • Use less of a harmful product • Reduce packaging and materials in products Figure 22.5 Integrated 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 that last longer and are recyclable, reusable, or easy to repair Fig. 22-5, p. 523

Solutions: 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.

What 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 items when reusable or refillable versions are available. Figure 22.6 Individuals 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

REUSE Reusing 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.

How People Reuse Materials
Children looking for materials to sell in an open dump near Manila in the Philippines. Figure 22-2

Case 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%).

REUSE Reducing resource waste: energy consumption for different types of 350-ml (12-oz) beverage containers. Figure 22-7

Glass drink bottle, used once
Aluminum can, used once Steel can, used once Recycled steel can Glass drink bottle, used once Recycled aluminum can Recycled glass drink bottle Figure 22.7 Reducing 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 times Energy (thousands of kilocalories) Fig. 22-7, p. 525

How 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.

Solutions: 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.

How 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.

• Buy beverages in refillable glass containers
What Can You Do? Reuse • Buy beverages in refillable glass containers instead 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 them when their useful life is over. • Carry groceries and other items in a reusable basket, a canvas or string bag, or a small cart. Figure 22.8 Individuals 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 cloth napkins, dishtowels, and handkerchiefs instead 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

RECYCLING Primary (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.

RECYCLING There 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.

How 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.

RECYCLING Composting 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.

RECYCLING Recycling 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.

How 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.

RECYCLING Reuse 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.

How 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.

Trade-Offs Recycling Advantages Disadvantages
Reduces air and water pollution Does not save landfill space in areas with ample land Saves energy Reduces mineral demand May lose money for items such as glass and most plastic Reduces greenhouse gas emissions Reduces solid waste production and disposal Reduces profits from landfills and incinerators Figure 22.9 Trade-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 biodiversity Can save money for items such as paper, metals, and some plastics Source separation is inconvenient for some people Important part of economy Fig. 22-9, p. 529

BURNING 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.

Burning Solid Waste Waste-to-energy incinerator with pollution controls that burns mixed solid waste. Figure 22-10

Wet scrubber Waste pit Bottom ash
Electricity Smokestack Turbine Steam Crane Generator Wet scrubber Furnace Boiler Electrostatic precipitator Waste pit Figure 22.10 Solutions: 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. Water added Bottom ash Dirty water Conveyor Fly ash Conventional landfill Waste treatment Hazardous waste landfill Fig , p. 530

Trade-Offs Incineration Advantages Disadvantages Expensive to build
Reduces trash volume Expensive to build Costs more than short-distance hauling to landfills Less need for landfills Low water pollution Difficult to site because of citizen opposition Concentrates hazardous substances into ash for burial or use as landfill cover Some air pollution Older or poorly managed facilities can release large amounts of air pollution Figure 22.11 Trade-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 production Sale of energy reduces cost Modern controls reduce air pollution Can compete with recycling for burnable materials such as newspaper Some facilities recover and sell metals Fig , p. 531

How 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.

Burying Solid Waste Most 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.

Pipes collect explosive methane as used as fuel
When landfill is full, layers of soil and clay seal in trash Topsoil Electricity generator building Sand Clay Methane storage and compressor building Leachate treatment system Garbage Probes to detect methane leaks Pipes collect explosive methane as used as fuel to generate electricity Methane gas recovery well Leachate storage tank Compacted solid waste Figure 22.12 Solutions: 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. Garbage Groundwater monitoring well Leachate pipes Leachate pumped up to storage tank for safe disposal Sand Synthetic liner Leachate monitoring well Sand Clay and plastic lining to prevent leaks; pipes collect leachate from bottom of landfill Groundwater Clay Subsoil Fig , p. 532

Trade-Offs Sanitary Landfills Advantages Disadvantages
Noise and traffic No open burning Dust Little odor Air pollution from toxic gases and volatile organic compounds Low groundwater pollution if sited properly Releases greenhouse gases (methane and CO2) unless they are collected Can be built quickly Low operating costs Groundwater contamination Figure 22.13 Trade-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 waste Slow decomposition of wastes Filled land can be used for other purposes Discourages recycling, reuse, and waste reduction No shortage of landfill space in many areas Eventually leaks and can contaminate groundwater Fig , p. 533

How 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.

Case 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

HAZARDOUS WASTE Hazardous 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).

What Harmful Chemicals Are in Your Home?
Cleaning Gardening • Disinfectants • Pesticides • Drain, toilet, and window cleaners • Weed killers • Ant and rodent killers • Spot removers • Septic tank cleaners • Flea powders Paint • Latex and oil-based paints • Paint thinners, solvents, and strippers Automotive • Stains, varnishes, and lacquers Figure 22.15 Science: 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 acid General • Solvents • Dry-cell batteries (mercury and cadmium) • Brake and transmission fluid • Glues and cements • Rust inhibitor and rust remover Fig , p. 534

Hazardous 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.

Hazardous 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.

How 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.

DEALING WITH HAZARDOUS WASTE
We can produce less hazardous waste and recycle, reuse, detoxify, burn, and bury what we continue to produce. Figure 22-16

Convert to Less Hazardous or Nonhazardous Substances
Produce Less Waste Manipulate processes to eliminate or reduce production Recycle and reuse Convert to Less Hazardous or Nonhazardous Substances Chemical, physical, and biological treatment Ocean and atmospheric assimilation Land treatment Thermal treatment Incineration Figure 22.16 Integrated 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 Storage Arid region unsaturated zone Waste piles Surface impoundments Salt formations Underground injection Landfill Fig , p. 536

Conversion 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.

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.

Radioactive contaminants Organic contaminants Inorganic
metal contaminants Poplar tree Brake fern Sunflower Willow tree Indian mustard Landfill Polluted groundwater in Oil spill Figure 22.17 Solutions: 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) Polluted leachate Decontaminated water out Soil Soil Groundwater Groundwater Rhizofiltration Roots of plants such as sunflowers with dangling roots on ponds or in green- houses can absorb pollutants such as radioactive strontium-90 and cesium-137 and various organic chemicals. Phytostabilization Plants such as willow trees and poplars can absorb chemicals and keep them from reaching groundwater or nearby surface water. Phytodegradation Plants such as poplars can absorb toxic organic chemicals and break them down into less harmful compounds which they store or release slowly into the air. Phytoextraction Roots of plants such as Indian mustard and brake ferns can absorb toxic metals such as lead, arsenic, and others and store them in their leaves. Plants can then be recycled or harvested and incinerated.

Can reduce material dumped into landfills
Trade-Offs Phytoremediation Advantages Disadvantages Easy to establish Slow (can take several growing seasons) Inexpensive Effective only at depth plant roots can reach Can reduce material dumped into landfills Some toxic organic chemicals may evaporate from plant leaves Figure 22.18 Trade-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 incineration Some plants can become toxic to animals Low energy use Fig , p. 538

How 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.

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.

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.

Mobile. Easy to move to different sites
Trade-Offs Plasma Arc Advantages Disadvantages Small High cost Produces CO2 and CO Mobile. Easy to move to different sites Can release particulates and chlorine gas Figure 22.19 Trade-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 elements Produces no toxic ash Fig , p. 538

How 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.

Long-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.

Deep Underground Wells
Trade-Offs Deep Underground Wells Advantages Disadvantages Safe method if sites are chosen carefully Leaks or spills at surface Leaks from corrosion of well casing Wastes can be retrieved if problems develop Existing fractures or earthquakes can allow wastes to escape into groundwater Figure 22.20 Trade-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 do Encourages waste production Low cost Fig , p. 539

How 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.

Low construction costs
Trade-Offs Surface Impoundments Advantages Disadvantages Groundwater contamination from leaking liners (or no lining) Low construction costs Low operating costs Air pollution from volatile organic compounds Can be built quickly Overflow from flooding Figure 22.21 Trade-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 necessary Disruption and leakage from earthquakes Can store wastes indefinitely with secure double liners Promotes waste production Fig , p. 539

How 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.

Long-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.

Secure Hazardous Waste Landfill
In the U.S. there are only 23 commercial hazardous waste landfills. Figure 22-22

Bulk waste Gas vent Topsoil Plastic cover Earth Impervious clay cap
Sand Clay cap Impervious clay Water table Figure 22.22 Solutions: secure hazardous waste landfill. Earth Leak detection system Groundwater Plastic double liner Double leachate collection system Reactive wastes in drums Groundwater monitoring well Fig , p. 540

• 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 to remove stains and mildew. Figure 22.23 Individuals 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

Case Study: Lead Lead is especially harmful to children and is still used in leaded gasoline and household paints in about 100 countries. Figure 22-24

Solutions Lead Poisoning Prevention Control
Phase out leaded gasoline worldwide Sharply reduce lead emissions from old and new incinerators Phase out waste incineration Replace lead pipes and plumbing fixtures containing lead solder Test blood for lead by age 1 Remove leaded paint and lead dust from older houses and apartments Ban use of lead solder Remove lead from TV sets and computer monitors before incineration or land disposal Ban use of lead in computer and TV monitors Figure 22.24 Solutions: 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 food Ban lead glazing for ceramicware used to serve food Test existing candles for lead Ban candles with lead cores Wash fresh fruits and vegetables Fig , p. 541

Case Study: Mercury Mercury 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

Solutions Mercury Pollution Prevention Control
Phase out waste incineration Sharply reduce mercury emissions from coal-burning plants and incinerators Remove mercury from coal before it is burned Convert coal to liquid or gaseous fuel Tax each unit of mercury emitted by coal-burning plants and incinerators Switch from coal to natural gas and renewable energy resources such as wind, solar cells, and hydrogen Collect and recycle mercury-containing electric switches, relays, and dry-cell batteries Figure 22.26 Solutions: 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 recycled Require labels on all products containing mercury Fig , p. 543

Fig. 22-25, p. 542 AIR WINDS PRECIPITATION WINDS PRECIPITATION
Hg and SO2 Hg2+ and acids Hg2+ and acids Photo- chemical Human sources Elemental mercury vapor (Hg) Inorganic mercury and acids (Hg2+) Inorganic mercury and acids (Hg2+) Coal- burning plant Incinerator Deposition Runoff of Hg2+ and acids Deposition WATER Large fish Vaporization Deposition Small fish BIOMAGNIFICATION IN FOOD CHAIN Deposition Figure 22.25 Science: 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? Phytoplankton Zooplankton Bacteria and acids Oxidation Elemental mercury liquid (Hg) Inorganic mercury (Hg2+) Organic mercury (CH3Hg+) Bacteria Settles out Settles out Settles out SEDIMENT Fig , p. 542

ACHIEVING 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.

Global 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.

Making 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.

Solid and Hazardous Waste

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