Global waste electronic and electrical equipment (WEEE) totalled 41.8 million tonnes in 2014, according to the UN.
In a report, it says the e-waste comprised resources, such as gold, silver and iron, worth $52 billion and contained high volumes of toxic material, including lead glass, mercury and cadmium, as well as 4,400 tonnes of ozone-depleting CFCs.
The UN found that most of the world's e-waste was not collected in 2014 for proper resource recovery or treatment of the toxic elements. It also calculated that less than one-sixth of the waste had been diverted from landfills to recycling and reuse.
"Worldwide, e-waste constitutes a valuable 'urban mine', a large potential reservoir of recyclable materials. At the same time, the hazardous content of e-waste constitutes a 'toxic mine' that must be managed with extreme care," commented UN under-secretary-general David Malone.
Large and small kitchen, bathroom and laundry equipment accounted for the majority of discarded electronic and electrical equipment, making up 60% of the stockpile of global e-waste. By contrast, just 7% of the 2014 total consisted of mobile phones, calculators, personal computers, printers, and other small information technology products.
The US, China, Japan, Germany and India produced the most e-waste by volume, while Norway, Switzerland, Iceland, Denmark and UK head the league of countries on per capita basis. In 2014, each citizen in the UK produced 23kg of WEEE, according to the report.
The UN calculates that about 6.5 million tonne or 15.5% of the WEEE generated in 2014 were treated through national take-back programmes.
The UN forecasts that the global volume of e-waste will rise by 21% to 50 million tonnes in 2018.