Electronic waste can contain 1,000 different substances including lead, cadmium, chromium and mercury - heavy metals which are highly toxic...This brew of toxic substances can damage nervous, kidney and reproductive systems, while some of the metals contain carcinogens...Despite the Basel Convention, which in 1994 banned the export of hazardous waste from rich to poor countries, electronic waste from the United States and to a lesser extent Europe, South Korea and Japan has ended up on Chinese shores, environmentalists say.