MONTREAL - Reduce, reuse and recycle can be environmentally challenging when it comes to a growing mountain of discarded consumer electronics created by the quest for all the latest gadgets.

More than 140,000 tonnes of electronic waste end up in Canadian landfill sites every year, says Jed Goldberg, president of Earth Day Canada.

"So, in the consumer's quest to have the brightest and the shiniest and the most up-to-date technology, that leaves some perfectly valuable electronic product sitting there compromised," he said.

Unfortunately, a lot of consumers don't know what to do with their discarded televisions, computers and video game consoles, he said from Toronto.

Earth Day Canada's mission is to improve the environment and help Canadians lessen their impact on it. Canadian communities planned hundreds of events to celebrate Earth Day Wednesday -- everything from e-waste pickups and community cleanups to festivals and lectures.

Both Earth Day Canada and Greenpeace support so-called "take back" programs, in which retailers and especially manufacturers take back devices to have them recycled.

"In the end, it has to be the producer that takes responsibility for recycling," said Iza Kruszewska of U.K.-based Greenpeace International's toxics campaign.

Globally, there could be as much as 20 million to 50 million tonnes a year of e-waste generated, said Kruszewska, citing figures from a United Nations environmental program.

"It's a huge disparity because nobody really knows," she said from London.

She said most of the top personal computer makers, such as Apple, Dell, HP, Lenovo and Acer, have committed to eliminating toxic chemicals, although Apple has moved more quickly than the others.

Kruszewska said the major PC manufacturers also are continuing to develop programs to take back old computers but they differ in their scope.

"The big problem is the individual consumer who doesn't know what to do with their product and has no where to take it in places like India or Latin America," said Kruszewska, who puts out quarterly evaluations of electronic companies' green efforts for Greenpeace.

Local authorities who deal with waste often don't have any idea of what "toxic" materials are in these products, such as vinyl plastic (PVC) and brominated flame retardants, she added.

TVs are a "huge, huge problem" because they are heavy and bulky and they have cadmium and mercury. Older sets have lead in them, Goldberg said.

"The problem we have is the 20-year-old TV set that sits in your basement that you never use. That's a toxic soup of who-knows-what is in that device," he said.

Mobile phones are another recycling challenge, noted Goldberg.

A recent UN report said there now are an estimated 4.1 billion mobile phone subscriptions worldwide, meaning more than half of the global population pays to use a cellphone.

In Canada, wireless carriers such as Rogers, Bell and Telus have cellphone recycling programs.

Wireless carriers have recovered more than 900,000 devices in the past three years, said the Canadian Wireless Telecommunications Association.