Dioxins & Furans

This group of micro-pollutants are classified as polychlorinated dibenzo dioxins/furans.

The toxic effects of dioxins are measured in fractional equivalencies of TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin), the most toxic and best studied member of its class.

Where does it come from ?

The toxicity is mediated through the interaction with a specific intracellular protein, the aryl hydrocarbon (AH) receptor, a transcriptional enhancer, affecting a number of other regulatory proteins.

Impact on people and the environment

While the affinity of dioxins and related industrial toxicants to this receptor may not fully explain all their toxic effects including immunotoxicity, endocrine effects and tumour promotion, toxic responses appear to be typically dose-dependent within certain concentration ranges. A multiphasic dose-response relationship has also been reported, leading to uncertainty and debate about the true role of dioxins in cancer rates.

The symptoms reported to be associated with dioxin toxicity in animal studies are incredibly wide ranging, both in the scope of the biological systems affected and in the range of dosage needed to bring these about. Acute effects of single high dose dioxin exposure include wasting syndrome, and typically a delayed death of the animal in 1 to 6 weeks. By far the most toxicity studies have been performed using 2,3,7,8-tetrachlorodibenzo-p-dioxin.