Discarded electronics. Every year, there is an enormous number of computer and electronic devices that become obsolete and are thrown in the trash. Lead, cadmium, mercury and other toxic materials used in this equipment can contaminate the environment. It was estimated that between 2003 and 2010, more than three billion consumer electronic devices were discarded.All over the world, recycling centers exist that handle e-waste properly, and people should dispose of old computers, phones, tablets and other electronics at such facilities. For a most unusual e-waste disposal story, see Apple 1.