Dioxane

Sources

The dioxanes are primarily formed residues when the three following conditions are met:

High temperatures (higher than 320°C) and/or incomplete combustion,
Presence of organic sulphuric acid,
Presence of chlorine.

In addition to these conditions of formation, four factors support the dioxane formation:

alkaline media,
the presence of ultraviolet radiation,
the presence of radicals (in chemical reactions).

The persistence of dioxanes supports a diffusion in all the mediums (air, water, ground, basement), the strongly contaminated zones constituting " sources-réservoirs".

The dioxin emissions come from four sources:

Chemical industry (Production or use of chlorinated products),
Proceeded thermal and of combustion (use of fuels, incineration, heat treatments…),
anarchistic Processes (in particular in the Compost S), starting from precursors,
secondary Emissions, starting from " sources-réservoirs".

For example, of dioxanes are emitted during the use of spark-ignition engine, in the wood combustion, or when one smokes of the tobacco. But the greatest source of dioxane released in the environment is related to the industrial activity and urban, via the Incinérateur S of waste and the coking plants (emissions atmospheric) and the rejections of chemical plants and paper mills (Immission and contamination of the grounds and water).

Examples of factors of dioxin emission:

Chemical properties

These molecules are very stable and they are all the more stable as the number of atoms of Chlore is important. This stability explains the difficulty of destroying them.

Effects on the Man

Because of their Lipophilia, they concentrate primarily in the lubricating mass of the animals. It thus is found all along the Food chain. The man being at the end of this chain, the food way is its principal way of exposure to dioxanes. It moreover was noted a tendency to the bio-accumulation of dioxane, the man being at the end of the food chain, it incurs the most risk to have a high dioxane concentration in the body.

Because of its stability, it is estimated that its half-life in the organization is about seven years. The man does not have a means to eliminate dioxane except natural degradation, but the woman can eliminate it by transfer in the placenta and the mother's milk. The people more at the risk are thus the babies.

A short-term exposure to high percentages of dioxane can be at the origin of cutaneous lesions, Chloracné and formation of dark spots on the skin for example, as well as a deterioration of the hepatic function.

A prolonged exposure can damage the Immune system, disturb the development of the Nervous system, be with the source of the disorders of the Système endocrinien and function of reproduction.

The Dioxine of Seveso is only the carcinogenic dioxane recognized for the man, according to the international Center of research on cancer. However, several other dioxanes are recognized as being Tératogène S and inducing a fœtotoxicity, falls of the Fertilité, as well as disorders endocriniens.

Contamination

The Catastrophe of Seveso implies the Dioxine of Seveso, the tétrachlorodibenzo-para-dioxane, dioxane TCDD, 2,3,7,8, similar to that contained in the Orange Agent poured with the Vietnam. In 1999, Belgium underwent a crisis of dioxane involving the demolition of many livestock (chickens), unsuitable with consumption.

Viktor Iouchtchenko was the victim of a poisoning by dioxane at the time of the electoral campaign in Ukraine of 2004.

French regulation

The European Committee for Standardization adopted the December 27th 1996 the standard INTO 1948 of measurement of dioxanes to the emission. This standard was transcribed in the form of standard AFNOR (French association of standardization) NF IN 1948.

The directive of December 16th 1994, transposed in French right by the decree of October 10th, 1996 (repealed and replaced by the decree of September 20th, 2002), imposes a limiting value on the emission of 0,1 ng/m ³ out of dioxanes with the installations of incineration and Co-incineration of dangerous industrial waste since July 1st 2000. The other incinerators of nondangerous waste (as UIOM) also have the obligation to respect this limiting value of 0,1 ng/m ³ since December 28th 2005 (stopped of September 20th, 2002 relating to the installations of incineration and Co-incineration of nondangerous waste and with the installations incinerating of waste of activities of care at the infectious risks).

The setting in conformity of the French park of incinerators (more than 300 units) with the ministerial decree of January 25th, 1991, allowed a first fall of the dioxane emissions, passing 1,1 kg in 1995 to 210 G in 2002, by UIOM. The reduction continued in 2005 (95 G by UIOM/an), while remaining still too high for the ministerial decree of September 20th, 2002. The dioxin emissions of the UIOM would have been divided by 100 of 1995 to 2006, grace also to the closing of the most polluting installations (there remain only 128 functioning UIOM).

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