Dioxins: chemical - historical - natural

Background information

The term dioxin refers to a large family of chemicals. They are polychlorinated aromatic compounds with a similar structure and similar chemical and physical properties. They are not produced intentionally, but are formed as a by-product of chemical reactions that span the spectrum from natural events such as volcanic eruptions and forest fires to anthropogenic processes such as the manufacture of chemicals, pesticides, steel and paint, the bleaching of pulp and paper, or exhaust emissions and waste incineration. For example, emissions from uncontrolled incineration of chlorinated waste in a waste incineration plant contain dioxins.

Of the 210 different dioxin compounds, only 17 are of toxicological concern. The most toxic dioxin that has been studied most thoroughly is 2,3,7,8-tetrachlorodibenzo-p-dioxin, abbreviated 2,3,7,8-TCDD. Dioxin is measured in "parts per trillion" (ppt).

Dioxins do not dissolve in water, but are very soluble in fat. This means that they form bonds with the sediment of water bodies and with organic substances in the environment and are absorbed into animal and human fatty tissue. In addition, they are not biodegradable, so they persist and accumulate in the food production chain. Once dioxins are released into the environment, via the air or water, this ultimately leads to their accumulation in the fatty tissue of animals and humans.

The danger to people and the environment posed by dioxins has been known to the general public since 1976, when an explosion at a chemical factory in Seveso, Italy, released two kilograms of dioxin, making the area uninhabitable for years and causing severe skin damage to people.

The “ultra-poison TCDD” (dioxin) is giving scientists a headache. How should one evaluate a substance to which even related laboratory animals react extremely differently: guinea pigs, for example, are 2.500 times more sensitive than hamsters. The transfer of animal experiments to humans is therefore speculative.

It was only in 1997 that the International Agency for Research on Cancer (IARC) decided to classify TCDD (dioxin) as carcinogenic to humans. The reason for the decision was, among other things, the observation that of over 5.000 chemical workers whose TCDD levels in their blood were 300-fold elevated, 15% more than expected had died of cancer. Even years later, their cancer mortality rate was on average 13% higher than that of the rest of the population. Those exposed to peak stress even saw their risk increase by 25%. The data collected at the same time for heart attacks and diabetes were unremarkable. In the case of diabetes, there was even a decrease with increasing dioxin levels.

If you look at the statistics more closely, the total number of all tumors is increasing significantly (significantly), but the increase cannot be attributed to a specific type of cancer. Until now, science had to assign a specific type of cancer to a specific substance in order to establish a causal connection. The few clear (significant) increases in certain types of cancer cannot explain the overall result. Cancer of the connective tissue occurred 11 times more often in the exposed group. However, the result becomes less explosive when you know that the statistics are only based on three cases. According to the authors, the increase in bladder cancer has nothing to do with dioxin, but is due to the chemical "4-aminobiphenyl" in the workplace. This substance is known to cause bladder cancer. Since the mortality (overall mortality) of chemical workers does not differ from that of the rest of the population, dioxin is wrongly called “ultra-poison”.

The most visible damage to health is disfiguring chloracne (severe skin changes). An effect on the central nervous system, which manifests itself in severe depression, is also likely. However, chemical accidents such as those in Seveso do not only result in dioxins: the effect of "chlorinated naphthalenes", which are closely related to dioxins, has hardly been investigated so far because experts have concentrated on TCDD (dioxin). (1)

Also natural sources

However, it has been known for several years that there are also natural sources. For example in the clay pits of the Westerwald. Here, significant quantities of dioxins from prehistoric volcanic activity were found in kaolinite (Bolus alba). And so generations of dioxins are likely to have been introduced into and into the body via bolus alba in the form of pills, cosmetics and baby powder. Completely without industrial chlorine chemistry and without the detour via animal nutrition.

300 years

Scientists also found dioxins (polychlorinated dibenzo-p-dioxins and dibenzofurans = PCDD/F) in the sedimentary rock of four Black Forest lakes. Amazing: The toxic sediment dates back to the 17th century - dioxin sources such as waste incineration plants or the production of chorphenols did not even exist back then. The researchers suspect that the cause was atmospheric pollution caused by the production of charcoal or the smelting of ores (2). Dioxins can also be produced when burning peat. [1]

Pure biological

Until now, dioxins were considered the most toxic organic substances produced by humans. But nature was once again faster: Dutch chemists proved that up to 20 different dioxins and furans are formed from chlorophenols in forest soils. The chlorophenols are also often of natural origin (3).

1. Steenland K et al. Cancer, heart disease, and diabetes in workers exposed to 2,3,7,8-Tetrachlorodibenzo-p-dioxin. Journal of the National Cancer Institute 1999, 91 pp.779-786
2. Ingrid Jüttner, Bernhard Henkelmann, Karl-Werner Schramm, Christian EW Steinberg, Raimund Winkler, and Antonius Kettrup Occurrence of PCDD/F in Dated Lake Sediments of the Black Forest, Southwestern Germany Environmental Science & Technology, 1997, 31, p. 806 - 811
3. Eddo J. Hoekstra, Henk de Weerd, Ed WB de Leer, and Udo A. Th. Brinkman Natural Formation of Chlorinated Phenols, Dibenzo-p-dioxins, and Dibenzofurans in Soil of a Douglas Fir Forest Environmental Science & Technology 1999, 33, S. 2543 - 2549

Links

[1] http://ticker-grosstiere.animal-health-online.de/20030227-00003/

This message was first posted at www.animal-health-online published. We thank you for permission to reproduce.

Source: Gyhum [Dr. Manfred Stein]