It's also the components of computers that release toxic substances, which leach into soils and threaten ground water. Computers are cornucopias of potentially hazardous chemicals. Most computer components contain nickel, lithium, cadmium, chromium, and mercury. Not only that, but there is more and more plastic being used in computers, and less precious metals. Plastics, unlike metals, aren't worth much to recyclers.
Computer monitors are the worst offenders of all.
A standard glass cathode ray tube, or CRT, contains up to eight pounds of lead. Because lead-coated glass particles can contaminate ground water, a standard monitor can be classified as hazardous waste. This year, Massachusetts became the first state to ban CRTs from landfills, and other states are following suit. The problem is compounded by the fact that recycling facilities haven't caught up with technology. The electronics recycling industry lacks the capacity to handle the large amounts of computers being discarded every year.