2.1 Introduction
`Dioxins' is a term used to describe a group of 210 compounds or `congeners' which contain either a dibenzo-para-dioxin or dibenzofuran nucleus substituted with chlorine.
Dioxins are highly toxic substances generally found at such extremely low concentrations that they challenge the limits of scientific measurement. They have been a source of international concern because they are a known by-product of some combustion processes and they do not readily break down, but persist in the environment.
A number of dioxin congeners have been shown to cause adverse health effects in humans, including cancer. Several international organisations have classified the most toxic congener-2,3,7,8-tetrachlorodibenzo-para-dioxin (2,3,7,8-TCDD)-as a human carcinogen.
Over the past 10-20 years, programs have been in place in NSW and elsewhere to eliminate known sources of dioxins from the manufacture of chemicals, including pesticides, emissions from waste incinerators and industry, and more diffuse sources such as backyard burning. These programs have resulted in significant reductions in their emissions.
Page last updated: 26 February 2011
