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Electronic waste

http://en.wikipedia.org/wiki/Electronic_waste

From Wikipedia, the free encyclopedia

Defective and obsolete electronic equipment

Electronic waste or e-waste describes discarded electrical or electronic devices. Used electronics which are destined for reuse, resale, salvage, recycling or disposal are also considered as e-waste. Informal processing of electronic waste in developing countries may cause serious health and pollution problems, as these countries have limited regulatory oversight of e-waste processing.

Electronic scrap components, such as CRTs, may contain contaminants such as lead, cadmium, beryllium, or brominated flame retardants. Even in developed countries recycling and disposal of e-waste may involve significant risk to workers and communities and great care must be taken to avoid unsafe exposure in recycling operations and leaking of materials such as heavy metals from landfills and incinerator ashes. Scrap industry and U.S. EPA officials agree that materials should be managed with caution^[1]

Contents

• 1 Definition
• 2 Amount of electronic waste world-wide
• 3 Global trade issues
  • 3.1 Guiyu waste dump
  • 3.2 Trade
• 4 Environmental impact
• 5 Information security
• 6 E-waste management
  • 6.1 Recycling
  • 6.2 Consumer awareness efforts
  • 6.3 Processing techniques
  • 6.4 Benefits of recycling
• 7 Electronic waste substances
  • 7.1 Hazardous
  • 7.2 Generally non-hazardous

1. Definition

Hoarding

Disassembling (center) and collecting

Electronic waste in Bengaluru, India

“Electronic waste” may be defined as discarded computers, office electronic equipment, entertainment device electronics, mobile phones, television sets, and refrigerators. This includes used electronics which are destined for reuse, resale, salvage, recycling, or disposal. Others are re-usables (working and repairable electronics) and secondary scrap (copper, steel, plastic, etc.) to be “commodities”, and reserve the term “waste” for residue or material which is dumped by the buyer rather than recycled, including residue from reuse and recycling operations. Because loads of surplus electronics are frequently commingled (good, recyclable, and non-recyclable), several public policy advocates apply the term “e-waste” broadly to all surplus electronics. Cathode ray tubes (CRTs) are considered one of the hardest types to recycle.^[2]

CRTs have relatively high concentration of lead and phosphors (not to be confused with phosphorus), both of which are necessary for the display. The United States Environmental Protection Agency (EPA) includes discarded CRT monitors in its category of “hazardous household waste”^[3] but considers CRTs that have been set aside for testing to be commodities if they are not discarded, speculatively accumulated, or left unprotected from weather and other damage.

The EU and its member states operate a system via the European Waste Catalogue (EWC)- a European Council Directive, which is interpreted into “member state law”. In the UK (a EU member state). This is in the form of the List of Wastes Directive. However, the list (and EWC) gives broad definition (EWC Code 16 02 13*) of Hazardous Electronic wastes, requiring “waste operators” to employ the Hazardous Waste Regulations (Annex 1A, Annex 1B) for refined definition. Constituent materials in the waste also require assessment via the combination of Annex II and Annex III, again allowing operators to further determine whether a waste is hazardous.^[4]

Debate continues over the distinction between “commodity” and “waste” electronics definitions. Some exporters are accused of deliberately leaving difficult-to-recycle, obsolete, or non-repairable equipment mixed in loads of working equipment (though this may also come through ignorance, or to avoid more costly treatment processes). Protectionists may broaden the definition of “waste” electronics in order to protect domestic markets from working secondary equipment.

The high value of the computer recycling subset of electronic waste (working and reusable laptops, desktops, and components like RAM) can help pay the cost of transportation for a larger number of worthless pieces than can be achieved with display devices, which have less (or negative) scrap value. In A 2011 report, “Ghana E-Waste Country Assessment”,^[5] found that of 215,000 tons of electronics imported to Ghana, 30% were brand new and 70% were used. Of the used product, the study concluded that 15% was not reused and was scrapped or discarded. This contrasts with published but uncredited claims that 80% of the imports into Ghana were being burned in primitive conditions.

2. Amount of electronic waste world-wide

A fragment of discarded circuit board.

Rapid changes in technology, changes in media (tapes, software, MP3), falling prices, and planned obsolescence have resulted in a fast-growing surplus of electronic waste around the globe. Technical solutions are available, but in most cases a legal framework, a collection, logistics, and other services need to be implemented before a technical solution can be applied.

Display units (CRT, LCD, LED monitors), processors (CPU, GPU, or APU chips), memory (DRAM or SRAM), and audio components have different useful lives. Processors are most frequently out-dated (by software no longer being optimized) and are more likely to become “e-waste”, while display units are most often replaced while working without repair attempts, due to changes in wealthy nation appetites for new display technology.

An estimated 50 million tons of E-waste are produced each year.^[1] The USA discards 30 million computers each year and 100 million phones are disposed of in Europe each year. The Environmental Protection Agency estimates that only 15-20% of e-waste is recycled, the rest of these electronics go directly into landfills and incinerators.^[6][7]

According to a report by UNEP titled, “Recycling – from E-Waste to Resources,” the amount of e-waste being produced – including mobile phones and computers – could rise by as much as 500 percent over the next decade in some countries, such as India.^[8] The United States is the world leader in producing electronic waste, tossing away about 3 million tons each year.^[9] China already produces about 2.3 million tons (2010 estimate) domestically, second only to the United States. And, despite having banned e-waste imports, China remains a major e-waste dumping ground for developed countries.^[9]

Electrical waste contains hazardous but also valuable and scarce materials. Up to 60 elements can be found in complex electronics.

In the United States, an estimated 70% of heavy metals in landfills comes from discarded electronics.^[10][11]

While there is agreement that the number of discarded electronic devices is increasing, there is considerable disagreement about the relative risk (compared to automobile scrap, for example), and strong disagreement whether curtailing trade in used electronics will improve conditions, or make them worse. According to an article in Motherboard, attempts to restrict the trade have driven reputable companies out of the supply chain, with unintended consequences.^[12]

3. Global trade issues

See also: Global Waste Trade

See also: Electronic waste by country

Electronic waste is often exported to developing countries.

4.5-volt, D, C, AA, AAA, AAAA, A23, 9-volt, CR2032, and LR44 cells are all recyclable in most countries.

One theory is that increased regulation of electronic waste and concern over the environmental harm in mature economies creates an economic disincentive to remove residues prior to export. Critics of trade in used electronics maintain that it is still too easy for brokers calling themselves recyclers to export unscreened electronic waste to developing countries, such as China,^[13] India and parts of Africa, thus avoiding the expense of removing items like bad cathode ray tubes (the processing of which is expensive and difficult). The developing countries have become toxic dump yards of e-waste. Proponents of international trade point to the success of fair trade programs in other industries, where cooperation has led to creation of sustainable jobs, and can bring affordable technology in countries where repair and reuse rates are higher.

Defenders of the trade^[who?] in used electronics say that extraction of metals from virgin mining has been shifted to developing countries. Recycling of copper, silver, gold, and other materials from discarded electronic devices is considered better for the environment than mining. They also state that repair and reuse of computers and televisions has become a “lost art” in wealthier nations, and that refurbishing has traditionally been a path to development.

South Korea, Taiwan, and southern China all excelled in finding “retained value” in used goods, and in some cases have set up billion-dollar industries in refurbishing used ink cartridges, single-use cameras, and working CRTs. Refurbishing has traditionally been a threat to established manufacturing, and simple protectionism explains some criticism of the trade. Works like “The Waste Makers” by Vance Packard explain some of the criticism of exports of working product, for example the ban on import of tested working Pentium 4 laptops to China, or the bans on export of used surplus working electronics by Japan.

Opponents of surplus electronics exports argue that lower environmental and labor standards, cheap labor, and the relatively high value of recovered raw materials leads to a transfer of pollution-generating activities, such as smelting of copper wire. In China, Malaysia, India, Kenya, and various African countries, electronic waste is being sent to these countries for processing, sometimes illegally. Many surplus laptops are routed to developing nations as “dumping grounds for e-waste”.^[14]

Because the United States has not ratified the Basel Convention or its Ban Amendment, and has few domestic federal laws forbidding the export of toxic waste, the Basel Action Network estimates that about 80% of the electronic waste directed to recycling in the U.S. does not get recycled there at all, but is put on container ships and sent to countries such as China.^{[15][16][17][18]} This figure is disputed as an exaggeration by the EPA, the Institute of Scrap Recycling Industries, and the World Reuse, Repair and Recycling Association.

Independent research by Arizona State University showed that 87-88% of imported used computers did not have a higher value than the best value of the constituent materials they contained, and that “the official trade in end-of-life computers is thus driven by reuse as opposed to recycling”.^[19]

3.1 Guiyu waste dump

Main article: Electronic waste in China

The E-waste centre of Agbogbloshie, Ghana, where electronic waste is burnt and disassembled with no safety or environmental considerations.

Guiyu in the Shantou region of China is a huge electronic waste processing area.^[15][20][21] It is often referred to as the “e-waste capital of the world.” The city employs over 150,000 e-waste workers that work through 16-hour days disassembling old computers and recapturing whatever metals and parts they can reuse or sell. The thousands of individual workshops employ laborers to snip cables, pry chips from circuit boards, grind plastic computer cases into particles, and dip circuit boards in acid baths to dissolve the lead, cadmium, and other toxic metals. Others work to strip insulation from all wiring in an attempt to salvage tiny amounts of copper wire.^[22] Uncontrolled burning, disassembly, and disposal causes a variety of environmental problems such as groundwater contamination, atmospheric pollution, or even water pollution either by immediate discharge or due to surface runoff (especially near coastal areas), as well as health problems including occupational safety and health effects among those directly and indirectly involved, due to the methods of processing the waste.

Only limited investigations have been carried out on the health effects of Guiyu’s poisoned environment. One of them was carried out by Professor Huo Xia, of the Shantou University Medical College, which is an hour and a half’s drive from Guiyu. She tested 165 children for concentrations of lead in their blood. 82% of the Guiyu children had blood/lead levels of more than 100. Anything above that figure is considered unsafe by international health experts. The average reading for the group was 149.^[23]

High levels of lead in young children’s blood can impact IQ and the development of the central nervous system. The highest concentrations of lead were found in the children of parents whose workshop dealt with circuit boards and the lowest was among those who recycled plastic.^[23]

Six of the many villages in Guiyu specialize in circuit-board disassembly, seven in plastics and metals reprocessing, and two in wire and cable disassembly. About a year ago the environmental group Greenpeace sampled dust, soil, river sediment and groundwater in Guiyu where e-waste recycling is done. They found soaring levels of toxic heavy metals and organic contaminants in both places.^[24] Lai Yun, a campaigner for the group found “over 10 poisonous metals, such as lead, mercury and cadmium, in Guiyu town.”

Guiyu is only one example of digital dumps but similar places can be found across the world such as Asia and Africa. With amounts of e-waste growing rapidly each year urgent solutions are required. While the waste continues to flow into digital dumps like Guiyu there are measures that can help reduce the flow of e-waste.^[23]

A preventative step that major electronics firms should take is to remove the worst chemicals in their products in order to make them safer and easier to recycle. It is important that all companies take full responsibility for their products and, once they reach the end of their useful life, take their goods back for re-use or safely recycle them.

3.2 Trade

Proponents of the trade say growth of internet access is a stronger correlation to trade than poverty. Haiti is poor and closer to the port of New York than southeast Asia, but far more electronic waste is exported from New York to Asia than to Haiti. Thousands of men, women, and children are employed in reuse, refurbishing, repair, and remanufacturing, unsustainable industries in decline in developed countries. Denying developing nations access to used electronics may deny them sustainable employment, affordable products, and internet access, or force them to deal with even less scrupulous suppliers. In a series of seven articles for The Atlantic, Shanghai-based reporter Adam Minter describes many of these computer repair and scrap separation activities as objectively sustainable.^[25]

Opponents of the trade argue that developing countries utilize methods that are more harmful and more wasteful. An expedient and prevalent method is simply to toss equipment onto an open fire, in order to melt plastics and to burn away non-valuable metals. This releases carcinogens and neurotoxins into the air, contributing to an acrid, lingering smog. These noxious fumes include dioxins and furans.^[26] Bonfire refuse can be disposed of quickly into drainage ditches or waterways feeding the ocean or local water supplies.^[18][27]

In June 2008, a container of electronic waste, destined from the Port of Oakland in the U.S. to Sanshui District in mainland China, was intercepted in Hong Kong by Greenpeace.^[28] Concern over exports of electronic waste were raised in press reports in India,^[29][30] Ghana,^[31][32][33] Côte d’Ivoire,^[34] and Nigeria.^[35]

4. Environmental impact

Old keyboards

The processes of dismantling and disposing of electronic waste in the third world lead to a number of environmental impacts as illustrated in the graphic. Liquid and atmospheric releases end up in bodies of water, groundwater, soil, and air and therefore in land and sea animals – both domesticated and wild, in crops eaten by both animals and human, and in drinking water.^[36]

One study of environmental effects in Guiyu, China found the following:

• Airborne dioxins – one type found at 100 times levels previously measured
• Levels of carcinogens in duck ponds and rice paddies exceeded international standards for agricultural areas and cadmium, copper, nickel, and lead levels in rice paddies were above international standards
• Heavy metals found in road dust – lead over 300 times that of a control village’s road dust and copper over 100 times^[37]

The environmental impact of the processing of different electronic waste components

^[38]

5. Information security

E-waste presents a potential security threat to individuals and exporting countries. Hard drives that are not properly erased before the computer is disposed of can be reopened, exposing sensitive information. Credit card numbers, private financial data, account information, and records of online transactions can be accessed by most willing individuals. Organized criminals in Ghana commonly search the drives for information to use in local scams.^[39]

Government contracts have been discovered on hard drives found in Agbogbloshie. Multi-million dollar agreements from United States security institutions such as the Defense Intelligence Agency (DIA), the Transportation Security Administration and Homeland Security have all resurfaced in Agbogbloshie.^[39][40]

6. E-waste management

6.1 Recycling

Computer monitors are typically packed into low stacks on wooden pallets for recycling and then shrink-wrapped.^[26]

See also: Computer recycling

Today the electronic waste recycling business is in all areas of the developed world a large and rapidly consolidating business. People tend to forget that properly disposing of or reusing electronics can help prevent health problems, create jobs, and reduce greenhouse-gas emissions.^[41] Part of this evolution has involved greater diversion of electronic waste from energy-intensive downcycling processes (e.g., conventional recycling), where equipment is reverted to a raw material form. This recycling is done by sorting, dismantling, and recovery of valuable materials.^[42] This diversion is achieved through reuse and refurbishing. The environmental and social benefits of reuse include diminished demand for new products and virgin raw materials (with their own environmental issues); larger quantities of pure water and electricity for associated manufacturing; less packaging per unit; availability of technology to wider swaths of society due to greater affordability of products; and diminished use of landfills.

Audiovisual components, televisions, VCRs, stereo equipment, mobile phones, other handheld devices, and computer components contain valuable elements and substances suitable for reclamation, including lead, copper, and gold.

One of the major challenges is recycling the printed circuit boards from the electronic wastes. The circuit boards contain such precious metals as gold, silver, platinum, etc. and such base metals as copper, iron, aluminum, etc. One way e-waste is processed is by melting circuit boards, burning cable sheathing to recover copper wire and open- pit acid leaching for separating metals of value.^[43] Conventional method employed is mechanical shredding and separation but the recycling efficiency is low. Alternative methods such as cryogenic decomposition have been studied for printed circuit board recycling,^[44] and some other methods are still under investigation.

6.2 Consumer awareness efforts

The U.S. Environmental Protection Agency encourages electronic recyclers to become certified by demonstrating to an accredited, independent third party auditor that they meet specific standards to safely recycle and manage electronics. This works to ensure the highest environmental standards are being maintained. Two certifications for electronic recyclers currently exist and are endorsed by the EPA. Customers are encouraged to choose certified electronics recyclers. Responsible electronics recycling reduces environmental and human health impacts, increases the use of reusable and refurbished equipment and reduces energy use while conserving limited resources. The two EPA-endorsed certification programs are: Responsible Recyclers Practices (R2) and E-Stewards. Certified companies ensure they are meeting strict environmental standards which maximize reuse and recycling, minimize exposure to human health or the environment, ensure safe management of materials and require destruction of all data used on electronics. Certified electronics recyclers have demonstrated through audits and other means that they continually meet specific high environmental standards and safely manage used electronics. Once certified, the recycler is held to the particular standard by continual oversight by the independent accredited certifying body. A certification board accredits and oversees certifying bodies to ensure that they meet specific responsibilities and are competent to audit and provide certification. ^[45]

Some U.S. retailers offer opportunities for consumer recycling of discarded electronic devices. ^[46] [47]

In the US, the Consumer Electronics Association (CEA) urges consumers to dispose properly of end-of-life electronics through its recycling locator at www.GreenerGadgets.org. This list only includes manufacturer and retailer programs that use the strictest standards and third-party certified recycling locations, to provide consumers assurance that their products will be recycled safely and responsibly. CEA research has found that 58 percent of consumers know where to take their end-of-life electronics, and the electronics industry would very much like to see that level of awareness increase. Consumer electronics manufacturers and retailers sponsor or operate more than 5,000 recycling locations nationwide and have vowed to recycle one billion pounds annually by 2016,^[48] a sharp increase from 300 million pounds industry recycled in 2010.

The Sustainable Materials Management Electronic Challenge was created by the United States Environmental Protection Agency (EPA). Participants of the Challenge are manufacturers of electronics and electronic retailers. These companies collect end-of-life (EOL) electronics at various locations and send them to a certified, third-party recycler. Program participants are then able publicly promote and report 100% responsible recycling for their companies.^[49]

The Electronics TakeBack Coalition^[50] is a campaign aimed at protecting human health and limiting environmental effects where electronics are being produced, used, and discarded. The ETBC aims to place responsibility for disposal of technology products on electronic manufacturers and brand owners, primarily through community promotions and legal enforcement initiatives. It provides recommendations for consumer recycling and a list of recyclers judged environmentally responsible.^[51]

The Certified Electronics Recycler program^[52] for electronic recyclers is a comprehensive, integrated management system standard that incorporates key operational and continual improvement elements for quality, environmental and health and safety (QEH&S) performance.

The grassroots Silicon Valley Toxics Coalition focuses on promoting human health and addresses environmental justice problems resulting from toxins in technologies.

The World Reuse, Repair, and Recycling Association (wr3a.org) is an organization dedicated to improving the quality of exported electronics, encouraging better recycling standards in importing countries, and improving practices through “Fair Trade” principles.

Take Back My TV^[53] is a project of The Electronics TakeBack Coalition and grades television manufacturers to find out which are responsible and which are not.

The e-Waste Association of South Africa (eWASA)^[54] has been instrumental in building a network of e-waste recyclers and refurbishers in the country. It continues to drive the sustainable, environmentally sound management of all e-waste in South Africa.

E-Cycling Central is a website from the Electronic Industry Alliance which allows you to search for electronic recycling programs in your state. It lists different recyclers by state to find reuse, recycle, or find donation programs across the country.^[55]

Ewaste.guide.info is a Switzerland-based website dedicated to improving the e-waste situation in developing and transitioning countries. The site contains news, events, case studies, and more.^[56]

StEP: Solving the E-Waste Problem This website of StEP, an initiative founded by various UN organizations to develop strategies to solve the e-waste problem, follows its activities and programs.^[42][57]

6.3 Processing techniques

Recycling the lead from batteries.

In many developed countries, electronic waste processing usually first involves dismantling the equipment into various parts (metal frames, power supplies, circuit boards, plastics), often by hand, but increasingly by automated shredding equipment. A typical example is the NADIN electronic waste processing plant in Novi Iskar, Bulgaria—the largest facility of its kind in Eastern Europe.^[58][59] The advantages of this process are the human’s ability to recognize and save working and repairable parts, including chips, transistors, RAM, etc. The disadvantage is that the labor is cheapest in countries with the lowest health and safety standards.

In an alternative bulk system,^[60] a hopper conveys material for shredding into an unsophisticated mechanical separator, with screening and granulating machines to separate constituent metal and plastic fractions, which are sold to smelters or plastics recyclers. Such recycling machinery is enclosed and employs a dust collection system. Some of the emissions are caught by scrubbers and screens. Magnets, eddy currents, and trommel screens are employed to separate glass, plastic, and ferrous and nonferrous metals, which can then be further separated at a smelter.

Leaded glass from CRTs is reused in car batteries, ammunition, and lead wheel weights,^[26] or sold to foundries as a fluxing agent in processing raw lead ore. Copper, gold, palladium, silver and tin are valuable metals sold to smelters for recycling. Hazardous smoke and gases are captured, contained and treated to mitigate environmental threat. These methods allow for safe reclamation of all valuable computer construction materials.^[18] Hewlett-Packard product recycling solutions manager Renee St. Denis describes its process as: “We move them through giant shredders about 30 feet tall and it shreds everything into pieces about the size of a quarter. Once your disk drive is shredded into pieces about this big, it’s hard to get the data off”.^[61]

An ideal electronic waste recycling plant combines dismantling for component recovery with increased cost-effective processing of bulk electronic waste.

Reuse is an alternative option to recycling because it extends the lifespan of a device. Devices still need eventual recycling, but by allowing others to purchase used electronics, recycling can be postponed and value gained from device use.

6.4 Benefits of recycling

Recycling raw materials from end-of-life electronics is the most effective solution to the growing e-waste problem. Most electronic devices contain a variety of materials, including metals that can be recovered for future uses. By dismantling and providing reuse possibilities, intact natural resources are conserved and air and water pollution caused by hazardous disposal is avoided. Additionally, recycling reduces the amount of greenhouse gas emissions caused by the manufacturing of new products.^[62]

Benefits of recycling are extended when responsible recycling methods are used. In the U.S., responsible recycling aims to minimize the dangers to human health and the environment that disposed and dismantled electronics can create. Responsible recycling ensures best management practices of the electronics being recycled, worker health and safety, and consideration for the environment locally and abroad.^[63]

7. Electronic waste substances

Several sizes of button and coin cell with 2 9v batteries as a size comparison. They are all recycled in many countries since they contain lead, mercury and cadmium.

Some computer components can be reused in assembling new computer products, while others are reduced to metals that can be reused in applications as varied as construction, flatware, and jewelry.^[61]

Substances found in large quantities include epoxy resins, fiberglass, PCBs, PVC (polyvinyl chlorides), thermosetting plastics, lead, tin, copper, silicon, beryllium, carbon, iron and aluminium.

Elements found in small amounts include cadmium, mercury, and thallium.^[64]

Elements found in trace amounts include americium, antimony, arsenic, barium, bismuth, boron, cobalt, europium, gallium, germanium, gold, indium, lithium, manganese, nickel, niobium, palladium, platinum, rhodium, ruthenium, selenium, silver, tantalum, terbium, thorium, titanium, vanadium, and yttrium.

Almost all electronics contain lead and tin (as solder) and copper (as wire and printed circuit board tracks), though the use of lead-free solder is now spreading rapidly. The following are ordinary applications:

7.1 Hazardous

Recyclers in the street in São Paulo, Brazil with old computers

• Americium: The radioactive source in smoke alarms. It is known to be carcinogenic.
• Mercury: Found in fluorescent tubes (numerous applications), tilt switches (mechanical doorbells, thermostats),^[65] and flat screen monitors. Health effects include sensory impairment, dermatitis, memory loss, and muscle weakness. Exposure in-utero causes fetal deficits in motor function, attention and verbal domains.^[66] Environmental effects in animals include death, reduced fertility, and slower growth and development.
• Sulphur: Found in lead-acid batteries. Health effects include liver damage, kidney damage, heart damage, eye and throat irritation. When released into the environment, it can create sulphuric acid.
• BFRs: Used as flame retardants in plastics in most electronics. Includes PBBs, PBDE, DecaBDE, OctaBDE, PentaBDE. Health effects include impaired development of the nervous system, thyroid problems, liver problems. Environmental effects: similar effects as in animals as humans. PBBs were banned from 1973 to 1977 on. PCBs were banned during the 1980s.
• Cadmium: Found in light-sensitive resistors, corrosion-resistant alloys for marine and aviation environments, and nickel-cadmium batteries. The most common form of cadmium is found in Nickel-cadmium rechargeable batteries. These batteries tend to contain between 6 and 18% cadmium. The sale of Nickel-Cadmium batteries has been banned in the European Union except for medical use. When not properly recycled it can leach into the soil, harming microorganisms and disrupting the soil ecosystem. Exposure is caused by proximity to hazardous waste sites and factories and workers in the metal refining industry. The inhalation of cadmium can cause severe damage to the lungs and is also known to cause kidney damage.^[67] Cadmium is also associated with deficits in cognition, learning, behavior, and neuromotor skills in children.^[66]
• Lead: Solder, CRT monitor glass, lead-acid batteries, some formulations of PVC.^[68] A typical 15-inch cathode ray tube may contain 1.5 pounds of lead,^[3] but other CRTs have been estimated as having up to 8 pounds of lead.^[26] Adverse effects of lead exposure include impaired cognitive function, behavioral disturbances, attention deficits, hyperactivity, conduct problems and lower IQ^[66]
• Beryllium oxide: Filler in some thermal interface materials such as thermal grease used on heatsinks for CPUs and power transistors,^[69] magnetrons, X-ray-transparent ceramic windows, heat transfer fins in vacuum tubes, and gas lasers.
• Perfluorooctanoic acid (PFOA): Found in Non-stick cookware (PTFE), used as an antistatic additive in industrial applications, and found in electronics. PFOAs are formed synthetically through environmental degradation and, in mice, after oral uptake. Studies in mice have found the following health effects: Hepatotoxicity, developmental toxicity, immunotoxicity, hormonal effects and carcinogenic effects. Studies have found increased maternal PFOA levels to be associated with an increased risk of spontaneous abortion (miscarriage) and stillbirth. Increased maternal levels of PFOA are also associated with decreases in mean gestational age (preterm birth), mean birth weight (low birth weight), mean birth length (small for gestational age), and mean APGAR score.^[70]
• Hexavalent chromium: A known carcinogen after occupational inhalation exposure.^[66]

There is also evidence of cytotixic and genotoxic effects of some chemicals, which have been shown to inhibit cell proliferation, cause cell membrane lesion, cause DNA single-strand breaks, and elevate Reactive Oxygen Species (ROS) levels.^[71]

• DNA breaks can increase the likelihood of developing cancer (if the damage is to a tumor suppressor gene)
• DNA damages are a special problem in non-dividing or slowly dividing cells, where unrepaired damages will tend to accumulate over time. On the other hand, in rapidly dividing cells, unrepaired DNA damages that do not kill the cell by blocking replication will tend to cause replication errors and thus mutation
• Elevated Reactive Oxygen Species (ROS) levels can cause damage to cell structures (oxidative stress)^[71]

7.2 Generally non-hazardous

An iMac G4 that has been repurposed into a lamp (photographed next to a Mac Classic and a flip phone).

• Aluminium: nearly all electronic goods using more than a few watts of power (heatsinks), electrolytic capacitors.
• Copper: copper wire, printed circuit board tracks, component leads.
• Germanium: 1950s–1960s transistorized electronics (bipolar junction transistors).
• Gold: connector plating, primarily in computer equipment.
• Iron: steel chassis, cases, and fixings.
• Lithium: lithium-ion batteries.
• Nickel: nickel-cadmium batteries.
• Silicon: glass, transistors, ICs, printed circuit boards.
• Tin: solder, coatings on component leads.
• Zinc: plating for steel parts.