E-gad! Americans discard more than 100 million computers, cellphones and other electronic devices each year. As "e-waste" piles up, so does concern about this growing threat to the environment.

Electronic waste is accumulating faster than anyone knows what to do with it, almost three times faster than ordinary household trash. Researchers at Carnegie Mellon University estimate that at least 60 million PCs have already been buried in U.S. landfills, and according to the National Safety Council, nearly 250 million computers will become obsolete between 2004 and 2009, or 136,000 a day. Where will all these gizmos go, and what impact will they have when they get there?

Before I started studying garbage for my book Garbage Land: On the Secret Trail of Trash, I had no clue that the computer on my desk was such a riot of precious-but-pernicious materials. A cathode ray tube (CRT) monitor contains two to eight pounds of lead; e-waste, including CRT televisions, is one of the largest sources of this toxic heavy metal in municipal dumps. Printed circuit boards are dotted with antimony, silver, chromium, zinc, tin and copper. My computer, if crushed in a landfill, might leach metals into soil and water. Burned in a trash incinerator, it would emit noxious fumes, including dioxins and furans. Though scrubbers and screens would catch much of those emissions, scientists consider even minute quantities of them, once airborne, to be dangerous. Prolonged exposure to some of the metals in electronic devices has been shown to cause abnormal brain development in children, and nerve damage, endocrine disruption and organ damage in adults.

The processes that give birth to computers and other electronic devices are also cause for concern. A 2004 United Nations University study found that it takes about 1.8 tons of raw materials--including fossil fuels, water and metal ores--to manufacture a desktop PC and monitor. Mining, the source of the semiprecious metals in electronics, is the nation's largest industrial polluter; 14 of the 15 largest Superfund sites, designated by the Environmental Protection Agency as containing hazardous …