Hazardous substances in WEEE

Many items in WEEE contain hazardous substances that can be released during:

  • destructive disassembly and recycling practices such as heating, crushing or shredding
  • landfilling
  • incineration.

Appropriate measures must be in place to identify and mitigate the hazards.

During normal use of electrical and electronic equipment there is no risk to human health or the environment because “nearly all the substances of concern are in a solid, non-dispersible form” (OECD, 2003b). However, they do pose a concern once they become WEEE and are either treated or disposed of.

The most common hazardous substances in WEEE are shown in table 9.

Table 9: Main hazardous substances in WEEE
Antimony
Arsenic
Asbestos
Barium oxide
Beryllium
Cadmium
Chlorofluorocarbons and hydro chlorofluorocarbons 		Chlorine or brominated flame retardants
Cobalt
Copper
Lead
Lithium
Mercury
Nickel 		Poly-chlorinated biphenyls
Selenium
Silver
Tin
Zinc

Source: Technical Guidance for the Environmentally Sound Management of Specific Waste Streams: Used and Scrap Personal Computers (OECD, 2003b); Environmentally Sound Management Used Mobile Telephones (http://ipmi.org/, PDF, 257 KB) (International Precious Metals Institute, 2003).

These substances are mainly contained in circuit boards, cathode ray tubes (CRTs), liquid crystal displays (LCDs), lamps, casings, wiring, batteries, refrigerant systems, and solder.

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Some of the hazards only relate to particular types of historical WEEE, because technological advances have reduced the use of that type of equipment. As a result, they will not be a significant problem in the future, although the replacement technology could contain other hazards that require different treatment. The best example of this is the switch from CRT monitors to LCD screens.

The European Union restriction on the use of certain hazardous substances in new electrical and electronic equipment (known as the RoHS directive) has banned the use of six hazardous substances from manufacturing processes:

  • cadmium
  • mercury
  • hexavalent chromium
  • polybrominated biphenyls
  • polybrominated diphenyl ethers
  • lead.

Many manufacturers and component suppliers, even outside of the European Union, now require RoHS compliance for all products. However, this is not necessarily the case for items entering the New Zealand market.

The onus is on the original equipment manufacturer and/or the recycler to identify which hazardous materials are present, because it varies greatly between the product, brand, age and model. It is the original equipment manufacturer’s role to keep recyclers informed of which hazardous materials are in their products.

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Last updated:15 March 2011