E-waste typically contains valuable and potentially toxic substances. Their composition is highly dependent on the appliance type, the manufacturer, the model, the date of manufacture and the age of the waste. For example, scrap IT and telecommunications equipment contain a higher proportion of precious metals than household appliances. The mobile phone contains more than 60 elements, from base metals like copper and tin, to special metals like lithium, cobalt, indium, antimony and precious metals like gold, silver, palladium.
At the same time, e-waste also contains contaminants, especially flame retardants in plastics and other components. The circuits found in most e-equipment can contain arsenic, cadmium, chromium, lead, mercury and other toxic chemicals. Obsolete refrigerators, freezers and air-conditioners contain ozone-depleting chlorofluorocarbonatres. In obsolete televisions and computer monitors with a cathode-ray tube, we find barium, cadmium, copper, lead, zinc, … Lead screen glass is part of this technology. Small household appliances contain heavy metals such as cadmium, cobalt, nickel, lead, antimony, etc. In addition to heavy metals, they also contain other dangerous substances, flame retardants, organic pollutants, toner powder, liquid crystals4.
The composition of e-waste is also affected by social economic conditions, the accessibility of the reuse market, recycling infrastructure, waste separation programs and regulation enforcement.
In general, e-waste consists of:
- metals – 60 %,
- plastic – 15 %;
- CRT and LCD monitors – 12 %,
- mixture of plastics and metals – 5 %,
- pollutants – 3 %,
- cables – 2 %,
- printed circuits – 2 %,
- other – 1 %.
Some electronic equipment and its components contain substances that are considered dangerous for the environment and human health if removed in an uncontrolled manner. Although these dangerous substances are usually only present in small amounts, they can leak into the soil, water or air and can cause serious environmental damage.
The main environmental risks of e-waste growth are the depletion of natural resources and the release of hazardous substances. By dumping e-products into landfills, we miss the opportunity to rebuild and reuse millions of tonnes of materials. At the same time, the renewal of these materials means that fewer raw materials are needed to produce new products.