The cellphones will join a growing pile of other discarded electronic equipment -- computers, monitors, televisions, audio equipment, batteries -- already posing a toxic hazard. The junk goes by various names: e-waste, e-scrap, e-garbage.

Scientists say the cast-off materials are dangerous because they contain high amounts of lead, mercury, cadmium and other materials capable of leaching out of landfills and contaminating groundwater.

"It is a ticking time bomb," says Jane Ammons, a Georgia Tech professor of industrial and systems engineering who heads a project to develop solutions to electronic garbage.

Just one large TV or computer monitor, she says, may contain up to 8 pounds of lead.

Experts studying the problem say the substances pose a hazard, especially to children, as dangerous as lead-based paint and leaded gasoline. The paint was banned for use in houses in 1978, and the gasoline additive was phased out in the 1980s.

Even traces of lead or mercury in the bloodstream can cause serious disabilities in children.

Cellphones, troublesome because they contain lead and the suspected human carcinogens arsenic, cadmium, and beryllium, exemplify the e-waste problem as millions are expected to be discarded, industry experts say.

"Because cellphones are so small, their environmental impacts might appear to be minimal," says Bette Fishbein, a senior fellow at Inform Inc., a national environmental research group based in New York. "But the growth in their use has been so enormous that the environmental and public health impacts of the waste they create are a significant concern."

There are more than 130 million cellphone subscribers in the United States, and they use the devices for an average 18 months before replacing them, according to a study last year by Fishbein.

In metro Atlanta, three out of four households have a cellphone -- the highest percentage of households in the nation. Nationally, two out of three households have a cellphone, says the New York-based Scarborough Research group.

The new rule taking effect Monday that allows users to change wireless companies without losing their phone number is expected to motivate millions of Americans to switch in the next few months.

Those who switch will need new phones. That's because the United States has several competing technical standards, forcing users to purchase a new phone when they change service providers. Europe, on the other hand, has a single technical standard, which allows users to keep their phone despite carrier changes.

Anticipating a deluge of discarded U.S. phones when the new rule begins to take effect, the wireless industry has posted a Web site -- www.recyclewirelessphones .org -- to provide information on how users can recycle their old devices.

Recycling limited

Recycling programs so far have met with only minimal success. Seth Heine, who runs a 4-year-old company called CollectiveGood in Tucker that collects used cellphones, estimates that only about 1 percent of old phones are being recycled or refurbished for reuse. Heine says CollectiveGood sells most of the phones it collects to carriers in Latin America and the Caribbean. That brings up another problem, Ammons says. Shipping refurbished phones to poorer countries means that the devices will end up in landfills in those nations.

Cellphones are only part of the e-waste problem. The federal Environmental Protection Agency estimates that this year alone, 90 million personal computers will become obsolete but fewer than 15 percent will be recycled.

Julian Powell is seeing a deluge of old computers. He is head of Zentech, an Atlanta firm that recycles computers, monitors, laptops, printers and other electronic devices and disposes of them in an environmentally friendly way.

Cellphones, he says, pale in comparison "to the tons of computer equipment that I am flooded with."

His firm, however, sees only a small part of the load. The vast majority of the nation's e-waste purportedly slated for recycling is actually shipped to developing countries, mostly in Asia, environmental groups contend.

As much as 80 percent of the electronic waste is dispatched to those countries, which have poor environmental standards and low wages. Those conditions encourage workers to risk their health to recover small amounts of gold, silver, copper and aluminum from the waste, Ammons says.

The rest of the material is tossed into landfills that pollute drinking water supplies and sicken people, she says.

Crisis for Asia

A study last year by five environmental groups -- including Greenpeace China and the Silicon Valley Toxics Coalition -- says that e-waste has reached crisis proportions in many parts of Asia.

"Rather than having to face the e-waste problem squarely, the United States has made use of a convenient, and until now hidden, escape valve -- exporting the crisis to developing countries in Asia," the report said.

Despite this, the Environmental Protection Agency estimates that 12 million tons of e-waste -- enough to fill 120,000 railroad cars -- soon will be jamming landfills in the United States.

Concerned about the growing piles of electronic junk, several states are taking steps to deal with the problem. In Georgia, state legislators last year formed the Computer Equipment Disposal and Recycling Council to study the problem over the next five years and offer solutions.

A possible step is to ban e-waste from municipal landfills.

A project that Ammons heads at Georgia Tech also promises solutions. Researchers are devising a system to recover and reuse every material contained within electronic wastes. That would help recyclers make a profit and make it convenient for people to dispose of their obsolete equipment.

Ultimately, Ammons says, manufacturers must be encouraged to design products that don't use hazardous material and are more easily recycled, reused or upgraded so that they don't have to be thrown away in the first place.

Disposal Tips

Georgia has numerous computer recycling companies. Some accept only from businesses, but others accept from homeowners and businesses. Some may require a fee to take the equipment. For a directory go to www.p2ad.org/comp_recycle.html on the Internet.

For more information call the Georgia Pollution Prevention Assistance Division at 404-651-5120.

Cellphones

Instead of tossing your old cellphone into a desk drawer or the trash can, you can take or send it to several collection sites for recycling or refurbishment. Some choices include:

• AT&T Wireless stores: Accepts wireless phones, accessories and batteries -- regardless of manufacturer or carrier -- for recycling.
  
  
• Cingular Wireless: Sends donated phones to the Wireless Foundation's Call to Protect program, which supports battered women's shelters. Customers also can drop off old rechargeable batteries at any Cingular Wireless retail store.
  
  
• Nextel retail stores: Collects old cellphones and donates the revenue from them to the American Red Cross' Armed Forces Emergency Services.
  
  
• ReCellular: World's largest reseller, refurbisher and recycler of used cellphones. It supports scores of programs that recycle phones for charities. For drop-off locations nearest you, go to www.wirelessrecycling.com/home/ on the Internet.
  
  
• Sprint: Accepts old cellphones at its retail stores to generate funds that benefit Easter Seals and other charities.
  
  
• Verizon Wireless: Uses proceeds from cellphones collected at its stores to support HopeLine, a program to prevent domestic violence. Verizon stores also collect spent rechargeable batteries.