Smarter Living: Stuff
Your Computer's Lifetime Journey
Photo: Mikael Miettinen/Flickr
Deep in an open-pit mine in South America, your computer's life journey begins. It will cross nearly all continents from the time its raw materials are collected, to the recycling of components back into those materials. It weaves its way through industrial mines, refineries and smelters, chip fabrication plants, and assembly lines. Once your favorite electronic companion travels by truck, ship, plane or train to you, its lifespan is short: three to five years on average. Then it will join the millions of other discarded computers tumbling through sorting and recycling facilities and shredders. Its circuit board will even be roasted to recover and sell precious metals. All too often, the journey ends where it began: buried in the ground . only this time it becomes a heap of landfill trash known as electronic waste, or e-waste, the fastest growing waste stream in the U.S.
Unraveling the complex supply chain that gives rise to the billion computers in use worldwide is a daunting task. But even a broad look at the main lifecycle stages for your computer reveals much more than meets the eye. From the metals, chemicals, energy and water used to make your microchip, circuit board and monitor to the sorting, shredding and smelting that will send these pieces into a new cycle of use, the journey your computer makes throughout its short lifetime will take many surprising twists and turns.
Your Computer Is Not Only "Made In China"
When you imagine how your computer came to life, you might think of California's Silicon Valley, long the epicenter for the high-tech industry. Images of clean rooms, bunny suits, and sophisticated machinery for polishing silicon wafers might come to mind. Or you might picture China, where all products seem to get their start. But your computer's environmental footprint includes a circuitous trip around the globe by way of some dirty mining operations before it reaches your desk.
The copper in your circuit board and wiring might originate at a Chilean mine, but pass through a smelter in Sweden. Tantalum, the metal used to make capacitors that store electric charges, likely gets its start in a coltan mine in Australia or the Democratic Republic of Congo, before making its way to Pennsylvania for processing. Tiny metal computer guts might travel to the Philippines or Malaysia, where your circuit board is assembled with beryllium mined in Kazakhstan for insulating your microprocessor. Gold for the semiconductor's ultra-thin wire connectors may come from a dusty mine in Australia, but the trace amounts of platinum used to make your hard drive's coating likely voyaged more than 5,000 miles from South Africa. And to hold everything in place, you probably have silver and tin from Peru or Mexico combined in the solder. Your hard drive may hail from Singapore, but the semiconductor chip might be built by workers in Ireland or Israel. And everything comes together for final assembly and a "Made in China" mark before being bundled in styrofoam and cardboard for a trip across the Pacific Ocean on a container ship.
At the start of the supply chain, heavy extractive industries mine the metals and silicon and pump the oil that will be refined to produce your computer components. Mining accounts for up to 10 percent of the world's energy consumption, and causes considerable air and water pollution. But beyond pollution, the sheer volume of waste generated to make a typical desktop computer is staggering: More than 500 pounds of fossil fuels alone are guzzled up--several times the weight of your computer--not to mention nearly 50 pounds of chemicals, and 1.5 tons of water. Metals, silicon and petroleum are among the main raw materials that undergo several transformations (largely through the intensive use of chemicals) to fit neatly in your computer's sleek casing.
Metals account for 30 to 50 percent of your computer, but many of us would be hard-pressed to identify the 20 or so commonly used to make the transistors, capacitors, circuit board, semiconductor and wires hidden inside. Copper, lead and mercury make up large quantities, each producing an environmental burden that can only be seen by looking behind the scenes. Finding enormous quantities of clean water--up to 500 gallons per second--is the challenge for mining copper, a highly conductive metal essential for semiconductors, circuit boards and wiring. The world's most productive copper mine is in Chile's Atacama Desert, which also happens to be the driest place on Earth. Although the mine is 100 miles from the sea, it must turn to desalination, a costly and energy-intensive source for new water supplies. Copper mining is also infamous for sulfuric acid produced when its solid waste tailings are exposed to air and water. Combined with metals such as lead, arsenic, and cadmium, tailings are highly toxic to plants, wildlife and people alike.
Lead was widely used for radiation shields in the early days of bulky desktop monitors, which contain between 4 and 8 pounds of the heavy metal. Several states have implemented strict rules for curbing rampant dumping of monitors in landfills to avoid groundwater contamination by lead, which is known to interfere with the human nervous and endocrine systems due to its capacity to accumulate in tissues. Although lead has been replaced by mercury as the chief metal of concern in the newer liquid crystal display (LCD) screens, it is still used for solder in motherboards.
Mercury poses no risk while you use your computer but since there is an estimated 4 to 12 milligrams in the fluorescent lights illuminating your screen, it's hazardous to those who produce and dispose of it. Furthermore, it can stay in the atmosphere for up to a year and travel thousands of miles, according to the EPA. Exposure to mercury in even trace amounts can lead to brain and kidney damage, and one-seventieth of a teaspoon can contaminate twenty acres of water, roughly the size of 15 football fields.
Unlike copper and gold mining, extracting silicon for a computer chip doesn't involve acidic slurries or cyanide leaching--just a lot of dust that can lead to a serious lung disease called silicosis. Silicon dioxide is the compound used to make a semiconductor chip, and it is in abundant supply in the earth's crust as quartz sand. The semiconductor business occupies a small percentage of the silicon market, but the relatively benign environmental impact of silica mining is offset by the chemically-intensive manufacturing process needed to turn pure sand into the high quality wafer that will supply your computer's brain power.
Plastic is often used for a computer's outside casing, as well as for covering internal and external wires, and in circuit boards. It starts out as petroleum before undergoing heat-intensive processing and chemical treatment for use in a computer. In addition to the well-known environmental impacts of petroleum extraction and refining, plastics are treated with brominated flame retardants (BFRs). Supplied in large part by the bromine industry in the United States and Israel, the trouble with flame retardants, especially BFRs, is that they are highly toxic contaminants that accumulate in our bodies and environments through the food web. The good news is that several manufacturers are phasing out these compounds.
CPUs: Microchips and Circuit Boards
Your computer has a brain--the microchip--which sits on a microprocessor, otherwise known as the central processing unit (CPU). It is often encased in plastic or ceramic and applied to the circuit board with tiny gold wires connecting it to other parts of the circuit board. Hundreds of steps are involved in manufacturing the silicon chip, which requires toxic chemicals and gases known as dopants to make it capable of conducting electricity. A microchip is tiny--weighing less than a teaspoon of water--but a voluminous amount of water and chemicals are used to make it. More than 70 pounds of water have been used to make just one chip weighing less than an ounce. And between 500 to 1,000 different chemicals are used to produce the layers of circuitry so vital to your computer's operation. These include phosphoric, sulfuric and nitric acids, and gases and solvents such as boron, phosphorus and ammonia. The result: a chemical stew of wastewater that continues to pollute Superfund sites with cancer-causing volatile organic compounds such as trichloroethane (TCA), a chemical widely used in the early days of Silicon Valley chip manufacturing before storage tanks leaked into community groundwater supplies.
Besides lead, copper and precious metals, your circuit board likely contains mercury and beryllium, the latter recognized to be a highly toxic carcinogen. Beryllium is useful for electrical connectors because it can withstand high heat, but certain smelters involved in recycling your computer's components won't even accept materials such as mercury and beryllium due to the dangers and costs involved in handling them safely.
In 2007, an estimated 42 million computer monitors were at the end of their lives, waiting in storage for disposal. The problem is that most of these monitors were made with several pounds of toxic components, including lead, barium, phosphorus, mercury, copper, and hexavalent chromium, the latter being used on steel parts to prote ct against corrosion despite its potential for damaging a person's DNA or causing asthmatic bronchitis.
More than 50 percent of a desktop monitor is glass, which sounds easy enough to recycle. But because one of the layers of glass is made with lead, special attention must be paid when handling a monitor at the end of its life. In deciding what to look for in a new computer, it's possible that one with the latest generation of mercury-free LED-backlit LCD screens might rise to the top of the list.
With the purchasing and disposal choices they make, consumers play a key role in shaping not only the footprint of individual computers but also industry output as a whole. In particular, it's important to bear in mind that:
- Laptops use approximately a quarter of the energy of a comparable desktop;
- Laptops use less material than comparable desktops, so their footprint is relatively smaller;
- If your desktop is seven or more years old, it is likely that it uses over ten times more electricity to run than a modern Energy Star laptop
For these reasons, the energy payback of replacing your electricity guzzler desktop by a modern laptop can be very short (less than one year). Seek out Energy Star-rated machines--the EPA has strengthened the Energy Star requirements for computers, making them on average 30 percent more efficient than comparable machines.
Of course, buying new products may have other environmental impacts beyond energy consumption (and it's contribution to global warming) such as requiring water for manufacture, creating potential water pollution, and extracting more resources, which contributes to loss of biodiversity. To address these concerns, seek out models selected by the Electronic Product Environmental Assessment Tool (EPEAT), created by the EPA and the nonprofit Greener Electronics Council. These bear an EPEAT Bronze or Silver rating based on 51 environmental criteria, 23 of which are required and 28 of which are optional. Largely using European Restriction of Hazardous Substances (RoHS) standards (including restrictions on cadmium, mercury, lead, hexavalent chromium and some brominated flame retardants), EPEAT requires incorporating a minimum of 65 percent reusable or recyclable components, a take-back service and the reduction or elimination of toxins in packaging. Silver and bronze models both meet all the required criteria; silver must also meet at least half of the optional ones.
If purchasing a desktop, also look for the 80 PLUS label.This means that the purchasing choices you make can have a large effect on several stages of the computer's journey. Buying a computer from a manufacturer known to use recycled materials in its products means less raw materials and energy used during manufacturing; finding a way to keep your computer longer or find a second use for it means you keep it out of the waste stream; and choosing a recycler intent on managing the challenging end-of-life stage responsibly implies less risks of toxic contamination to people and the environment.
DISPOSAL AND RECYCLING
The latest EPA statistics show that fewer than 20 percent of computers are recycled in the U.S. and in 2007 alone, an estimated 112,000 computers were thrown away every day. Millions are lurking in closets awaiting disposal, which is getting easier thanks to the efforts of drop-off collection programs, manufacturer take-back options and recyclers who accept computers from individuals for a small fee.
When properly handled, 100 percent of a computer's parts can be recycled. However, the process is not typically a profitable one due to all the hand labor and expensive equipment .thus many computers are handled irresponsibly (see "E-waste: Saving Developing Communities From our Electronic Junk.") When handled by unscrupulous recyclers, computers end up in China, India and Africa nations where they are dismantled in primitive conditions over open fire and acid baths, resulting in contaminated waterways and exposures to the heavy metals and toxic compounds among workers and local residents.
Choosing e-Steward certified recyclers is your best option to ensure responsible handling (see "e-Stewards: Certifying Responsible Electronics Recyclers" for a full description of this certifier.)
Here's what happens to a computer once it's in the right hands.
containing cathode ray tube (CRT) glass are shipped to a lead smelter in North America for recovery of the contained lead in the tubes. The glass is cleaned and separated into its types: funnel glass, the part that contains 20-25% lead, and lead-free panel glass. Glass is then shipped to a manufacturer who uses it to make new tubes.
are shredded and sent to a copper smelter where almost all of the metals are recovered. Precious metals, including gold, silver and palladium are most valuable, but base metals such as copper, lead, tin, and nickel are important too. Resins used in manufacturing circuit boards now become a source of energy (heat), and the glass matte will be reused in roads, aggregate for roofing materials, and sand blasting media.
must first be identified by chemistry, often nickel cadmium, nickel metal hydride or lithium ion. Contacts are taped so the battery will not short and cause a fire when combined with similar batteries.
first have their circuit board removed for shipment to the copper smelter for recovery. The rest of the hard drive is shredded, taking special care to destroy all data. This produces fractions of aluminum and steel, which are separated and sold to material accumulators who turn around and resell the scrap to aluminum and steel manufacturers.
are shredded and steel is removed for resale to material accumulators. The non- steel portion is included with the circuit boards shipped to the copper smelter.Wire is removed and kept separate. When a large enough quantity is gathered, it is sent to a wire chopper to recover the copper destined for a copper mill that specializes in making new wire./p
are separated into categories for steel or aluminum and shipped to a material accumulator to re-produce "new" metal. Plastic cases are recycled by companies specializing in plastics and used to make new plastic items, which could include the housing for a brand new computer.
last revised 11/30/2011