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Dioxins, furans and PCBs

Chemical names

  • Polychlorinated dibenzo-p-dioxins (PCDDs, dioxins)
  • Polychlorinated dibenzofurans (PCDFs, furans)
  • Polychlorinated biphenols (PCBs)

Sources

These are formed by activities like combustion of wastes (including medical and hazardous wastes), crematoria, metallurgical industries (including metal smelting, refining and recycling), industrial and domestic coal and wood combustion, exhaust emissions from vehicles, controlled burn-offs, uncontrolled and accidental fires (including landfill fires).

Effects on health

Dioxins and furans can adversely affect human and animal health in a number of ways, including affecting the immune and reproductive systems, liver damage, neurobehavioural development, birth defects and cancer. The most noted health effect in people exposed to large amounts of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) is a skin effect known as chloracne. The International Agency for Research on Cancer (IARC) has determined that 2,3,7,8-TCDD is a human carcinogen (that is, it can cause cancer in humans).

High levels of PCBs cause chloracne, skin rashes, liver problems and eye irritation. Animal studies have shown developmental effects and there are reports of reduced short-term memory in children of mothers exposed to PCBs through what they eat.

We do not know whether PCBs cause cancer in people. The United States Environmental Protection Agency (USEPA) has classified PCBs as probable human carcinogens (Group B2). For more information see the USEPA’s air toxics website.

Groups that are most sensitive to dioxins, furans and PCBs

Humans, particularly foetuses and young children, and some animals.

Guideline values to protect health

New Zealand does not currently have inhalation guideline values for dioxins and furans. The Ministry has developed seven national environmental standards that ban activities that discharge significant quantities of dioxins, furans and other toxics into the air. For further details readers are referred to the Updated Users Guide to Resource Management (National Environmental Standards Relating to Certain Air Pollutants, Dioxins and Other Toxics) Regulations 2004 (Including Amendments 2005).

Ambient levels in New Zealand

The Ministry has considerable information on the levels of dioxins, furans and PCBs in the air and other parts of the environment. Generally, concentrations of these pollutants are low when compared to ambient concentrations found in other countries. Dioxin levels in air were, however, found to be seasonally elevated during colder months when more wood is burnt for domestic heating.

School incinerator covering school playground with smoke [photo].

Incinerators burning rubbish can produce a range of pollutants, affecting people and the environment. Source: Wellington Regional Council

 

Last updated: 17 July 2009