Dioxin

Dioxin, the endless story

Dioxin is since long time known as one of the strongest poisons which man is able to produce. It causes cancer of liver and lung, interferes in the immune system resulting in a predisposition to infectious diseases and embrional misgrowth.

At the beginning of the 20th century the production of chlorine splitting sodium chloride by Dow Chemical Midland,USA free chlorine could be used for many new compounds like pesticides, plastics such as PVC,chlorine bleaching of paper and many other sources. Dioxins are also built as unwanted side reactions during the production of chlorinated products.

When these new compounds are burned as waste, chlorine atoms combine with carbon resulting dioxins. Dioxin is also originated during combustion, mainly by heat under 780 $^{o}$ C It is therefore found in the atmosphere and in the fallout in rain. A main source of dioxin is used discarded motor oil and in some geological formations like kaolinite . In the press dioxin was cited in relation to the accident at the chemical plant of Hoffmann-LaRoche in Seveso, Italy. Due to an explosion a great amount of 2,3,7,8 TCDD dioxin was spread over the city of Seveso in 1976. Limits for dioxin expressed as tolerable daily intake are given in picogram 1 pg=10 $^{-12}$ g :

Germany 1 picogram (10 $^{-12}$ g) per Kg body weight
Netherland4 pg (4X10 $^{-12}$ g) per Kg body weight
Canada 10 pg (10X10 $^{-12}$ )g per Kg body weight
FDA from USA 0,03pg (0,03X10 $^{-12}$ g) per Kg body weight
Environmental administration EPA from USA 0,006pg (0,006X10 $^{-12}$ g) per Kg body weight

Please note that sometimes dioxin values are expressed in nanograms.
One nanogram=10 $^{-9}$ g.

Today emission of smoke stacks has been reduced from 400g i-TE/year in 1988 down to 2g i-TE/year.According to German regulations emission of smoke stacks over 5000 m $^{3}$ /h the emission should be reduced to 0,1 ng i-TE/ m $^{3}$

Sludge from industrial wastewater should not exceed 100 ng i-TE/kg of dry matter according to German regulation.
Soil of playground for children should not exceed 100 ng i-TE/kg of dry matter.
Soil of residential neighborhood should be kept under 1000 ng i-TE of dry matter according to the List of Berlin 1996.

Chemical structure of dioxins

There are about 210 dioxins and related compounds called furanes. They are classified in two classes of chemical compounds: The class of the polychlorinated dibenzo-p-dioxins and the class of the dibenzofuranes. The difference between dioxins and furanes is that some compounds have an oxigen bridge, others don't. Both classes of compounds are usually called dioxins.

The most poisoning dioxin is 2,3,7,8-TCDD (tetrachlorodibenzo-p-dioxin)(described by Sandemann et all. in 1957) therefore equivalents are calculated in relation to this compound as only 17 of the 210 dioxins and furanes have a chlorine atom at the position 2,3,7 and 8 being therefore strongly toxic and are expressed as Toxicity Equivalence (TE)
TCDD is classified as carcinogenic class I which is the highest step in the classification of the IARC (International Agency of Research of Cancer).
1 ng TE means that there is a mixture of PCDD and PCDF present which corresponds to 1 nanogram of 2,3,7,8 TCDD.

Dioxins are stored in liver an fat tissue and it takes about 10 years for the body to reduce half of the amount of once stored dioxins.
Other dioxins furanes and related compounds presenting toxicity:
PCDDs (Polychlorinated dibenzodioxin)
PCDFs (Polychlorinated dibenzofurans)
PCBs (Polychlorinated biphenyls)

Dioxins are very difficult to be analysed. PCB Polychlorated biphenil are most all the time present together with dioxins. PCBs are much more easy and is does not take so much time to analise as dioxins. Therefore PCB control with GC/MSD or HRGC/HRMS is used as indicator for dioxins. In milk a contamination of 100 ng/g of PCB in fat is an indicator of high dioxin values. In egg yolk a maximum of 60 ng/g in fat stands for tolerable values of Dioxins

The Belgian scandal of dioxin

In June 1999 Europe was confronted by the news of the scandal of dioxin in Belgian animal feed. Eggs, meat of hen, pigs and beef were not safe. Belgian animal feed had been enriched with old used engine oil with high level of dioxin.

As Belgic exported the contaminated meat as animal feed all over Europe was to be considered as bearing PCBs and dioxins.

Later on Swiss animal feed also was found to be contaminated by dioxins. This was caused by certain charges containing kaolinite from Germany. Kaolinite is part of earth which is used in the production on porcelain. As 3% in animal feed it is used to improve the flow during pumping when moving the animal feed from one store to another. German kaolin with high level of dioxin had also been added to animal feed in Austria and Germany. In June 1999 animal feedings with added kaolinite were found to have 1,5 to 30 pg i-TE/g resulting in a contamination of German turkeys of 30,6 pg i-TE/g fat. According to German regulation from 9.6.99 a maximum of Dioxin equivalents should be observed in following foods:
Eggs maximum of 4 pg i-TE/g fat
Poultry maximum of 5 pg i-TE/g fat
Milk maximum of 3 pg i-TE/g fat
Beef maximum of 6 pg i-TE/g fat
Pork maximum of 2 pg i-TE/g fat

French animal feed now found to carry dioxins tells that there is still very much wrong. Everything is being used to feed animals. As chalk is needed to feed cows chalk from washing of combustion gases had been added to citric pellets from Brazil which were fed to German cows. Great amount of milk had to be discarded because of high level of dioxin.

Even sewage sludge resulting from industrial waste water treatment is being added to animal feed, often without separation between the waste water and the normal sewage system.
In 1991 the use of sewage sludge from industrial waste water for animal feed was forbidden by the EU but this has not always been followed. In 1998/1999 French knackeries and gelatine factories as well as Dutch companies had sewage sludge from industrial waste water mixed with animal feed. Pigs and chicken fed with it were also sold in Germany.
Sewage sludge concentrates heavy metals, dioxin, antibiotics and resistant bacteria[542]
Sewage sludge is still being used in France ( November 1999) as ingredient to animal feed disregarding EU regulation of 1991. This confirms the deep distrust of the consumer confidence on public institutions.

European animal feed directive

Forbidden : Industrial waste water sludge is forbidden as animal feed. All components of sewage remain are not allowed to be added to animal feed even if they were submitted to any technological procedure.

Exception: Allowed is process Water which come out of closed circuits and which does not contain substances which are not allowed for animal feed. In 1999 faeces were found in French animal feed with added sewage. Recycled oils and fats are allowed as animal feed by way of exception under the control of an HACCP system.

Unfortunately many industrial waste water sludges are being declared as process water evading the European directive.

Unilever Chairman pleas for an EURO- FDA

To conter the loss of the consumers confidence and to restore the ability of the public veterinary and food control to do their job Antony Burgmanns Chairman of Unilever NV, Rotterdam says ( 14.11.99) that the creation of an European Control System like the US FDA will be necessary[583].

Dioxin in foods

Low levels of dioxin from environment are present in vegetables and all other kind of foods. The amount of environmental dioxin is not relevant, excluding the region of Seveso and some parts of Serbian. Eggs, milk, beef and fish all over Europe can have high amount of dioxin when animal feed with dioxin had been fed.

As dioxin accumulates in fatty tissue it is possible to reduce the intake of dioxin by eating less greasy fatty food. Therefore veterinary officials claim analytical checks on dioxin and PCBs when the food bears more than 2% of fat on exports from Belgium.

Despite the criminal procedures on the scandal of dioxin contaminated animal feed from Belgium the WHO reports decreasing levels of dioxins in worldwide human blood plasma. This is told to be a result of efforts to reduce dioxin in environment. So mother's milk in Germany being reported in 1985 as average of 29,6 ng i-TE/kg fat has decreased to an average of 15,9 ng i-TE/kg fat in 1994.

BSE problems in Great Britain, dioxin in Belgian foods caused gigantic financial losses to the involved industry and commerce. It disregarding laws and good manufacturing practice does not bring wealth. It soon or later ends in scandals. It should be a lesson to all who want to earn easy money without regarding safety and public health. Industry,great retailers and last but not least the consumer should help to keep food safe paying appropriate prices to their suppliers avoiding price battles which end on outlaw practices.
The WHO Consultation of May 25-29, in Geneva, Switzerland regarding the health risk of Dioxins[522] shows that the most important amount of dioxins intake resulting from food (90% of total human exposure to dioxins) has been reduced about half of the former values due to increased emission reducing activities. Food born dioxins are found mainly in animal fat. That is why vegetarian food becomes more attractive. But remember: Supplementation of vegetarian diets with B12 vitamin from drugstore is important to avoid undersupply.

According to the consultation of WHO the contamination of food is primarily caused by deposition of emissions from various sources (like waste incineration and production of chemicals) on farmland and waterbodies followed by bioaccumulation up terrestrial and aquatic food chains. Other sources may include contaminated feed for cattle, chicken and farmed fish so what has happened lately with Belgian animal feed, improper application of sewage sludge, flooding of pastures, waste effluents and certain food technologies.

Tolerable daily intake (TDI)

The WHO in December 1990 in the Netherlands established a tolerable daily intake (TDI) of 10 pg/kg by weight for TCDD.

The consultation concerning health risk of dioxins in May 1998, Geneva re-evaluated the TDI as an upper range of the TDI of 4 pg TEQ/kg by weight should be considered a maximal tolerable intake on a provisional basis and that the ultimate goal is to reduce human intake levels below 1 pg TEQ/kg bw/day. In Germany the human exposure to TCDD is supposed to be only 45% of the limit of 1 pg TEQ/kg bw/day.
The consultation however recommended that every effort should be made to limit environmental releases of dioxin and related compounds to the extent feasible in order to reduce their presence in the food chains, thereby resulting in continued reduction in human body burdens. Efforts to reduce the exposure of more highly exposed sub-populations should be undertaken. These efforts bear their price and this should be honored by commerce and by the consumer. Someone has to pay for it. So honest prices for good honest raw materials to reduce risk in food.

Accidental exposure to dioxin

Accidental exposures had taken place in Seveso and fires in PCB filled electrical equipment, that is why PCBs are being changed in such equipments. Some foods were also accidently contaminated such as an edible oil Yusho (Japan) and Yu-Cheng (Taiwan). Other heavy exposure to dioxins took place in Vietnam resulting from aerial spraying of forests with agent orange (TCDD) contaminating airforce personal and inhabitants of Vietnam.

Maximum levels for specific contaminants in foodstuffs Three important regulation apply from 1 March 2007: Regulation (EC) 1881/2006 sets maximum levels for specific contaminants in foodstuffs. [523] Regulation 1882/2006 sets out the methods testers must use in sampling and analysis for the control of nitrate levels in lettuce and spinach. [524] Regulation 1883/2006, deals with sampling and analysis methods for determining the levels of dioxins and dioxin-like PCBs in specific foodstuffs.[525]
Much attention is given to mycotoxins, such as setting limits on deoxynivalenol and zearalenone, including cereal bran marketed for direct human consumption and for germination.

The limits of lead in cows milk is extended to sheep and goat milk and their productslike cheese. The maximum level of lead in fish was risen from 200 mg/kg to 400 mg/kg to comply with the value of the Codex Alimentarius.

The limit on levels of cadmium found in the liver and kidney has been extended to include horse meat.

Dioxins: Farmed game are excluded from the limits of dioxins and dioxin-like PCBs set for meat and meat products. The limits set for liver, derived products, and fat is now restricted to bovines, sheep, poultry, pigs.

Swiss thickening agent Guar Gum with dioxin

[526]
According to the European Commission of an edible thickening agent called guar gum (E412), used in a variety of pre-prepared foods, may contain dioxin and pentachlorophenol contamination. Member States were asked to test all batches of guar gum imported Indian.

High levels of dioxin had been found on the 13.07.2007 in a Swiss-made thickening agent Unipektin branded VIDOCREM with levels of up to 156 picograms of dioxin per gram of fat in additives have been found (Maximum allowed= 6 picograms) .

Official issues claim that there is no immediate health risk to consumers, but as these chemicals have the potential for a range of toxic effects such as high risk of cancer, people shouldn't be exposed to them unnecessarily.

Consumer should avoid products which have thickening agent guar gum in their ingredient list.

The contaminated guar gum had been exported by the India Glycols Limited company.