Dioxins and their effects on human health
World Health Organization, Fact sheet N°225 June 1999
Assessment of the health risk of dioxins: re-evaluation of the Tolerable Daily Intake (TDI)
WHO Consultation May 25-29 1998, Geneva, Switzerland
From the WHO Factsheet
Exposure
Reducing dioxin intake is good public health policy and an important aspect of sustainable development. In 1998 WHO convened a consultation in Geneva to evaluate the tolerable daily dose of dioxins to which a human can be exposed without harm, the Tolerable Daily Intake (TDI). In light of new epidemiological data concerning dioxins' effects at low levels of exposure and based on animal studies, the TDI was reduced from 10 picogrammes/kilogram body weigh to a range of 1 to 4 picogrammes/kilogram body weight. The current levels of exposure in industrialized countries are in the range of 1 to 3 picogrammes/kilogram body weight. The TDI recommended by the WHO consultation is internationally recognized as a reference value for ensuring that safe levels of exposure are not exceeded.
Analysis
The analysis of dioxins requires sophisticated methods that are available only in a limited number of laboratories around the world. About 100 laboratories are able to analyse dioxins in environmental samples (e.g. ashes, soil, or water) and in food but about 20 laboratories in the world are able to reliably measure dioxins in biological materials (e.g. human blood or mother's milk). These are mostly in industrialized countries. Costs vary according to the type of sample, but range from US $1,200 for the analysis of a single biological sample to US $10,000 or more for the comprehensive assessment of release from a waste incinerator.