Dioxins are a family of 75 synthetic (manufactured) persistent, bioaccumulative, carcinogenic toxins. The forms are called congeners. They are produced whenever chlorine-based products such as plastics are burned, during bleaching processes at paper mills, during pesticide manufacture, and as part of smelting. Industrial facilities burning municipal and medical wastes can be significant sources of dioxins. They can persist in the environment for hundreds of years; their half life in the body is 7 years. Dioxins are now omnipresent; in the air, the soil and the food chain.
Effects from dioxin poisoning of humans include chloracne, reduced libido, cancer, sterility, damage to the immune and nervous systems, developmental disorders and infants with birth defects. Dioxins lodge in body fat and are not excreted; indeed they are passed on from a pregnant woman to her foetus through the placenta and via breast milk. They mimic the effects of natural hormones like oestrogen.
The level of dioxin considered acceptable in food may vary by a factor of 1000, from an daily intake of 0.01 picograms per kilogram of the consumer's body weight in one Western country to 10 picograms per kg in another. WHO has set its level at 4 picograms per kg, but it agrees with the consensus that there is no such thing as safe, because dioxin accumulates in the body. A picogram is 10-12 g.
In 1998 scientists advised the WHO to cut its recommended maximum daily intake of dioxins tenfold, due to the ability of such chemicals to cause brain damage at lower levels than that which cancer occurs. Brain damage can occur at levels 1000 times lower that is required for cancer.
Research at the university of Groningen (Netherlands) found that babies exposed to higher dioxin levels through breast milk did worse at standard tests for cognitive skills.
Chlorinated chemical production and disposal through incineration are the major sources of dioxin formation. Dioxin is ubiquitous in the bodies of the world's population, with the highest concentrations in mothers' breast milk. Dioxin is linked to cancer, and a host of other health effects at minute doses that especially impact the developing fetus and newborn.
According to a 1999 research, 95-98% of total human exposure to dioxins was directly related to the consumed food. About 90% of usual dioxin consumption comes from eating meat, dairy products and fish.
In the USA and France, daily exposure is about 1.2 picograms.
Dioxin – present in 'Agent Orange' – was used by the USA as a defoliant in the Vietnam War. Over 2 million people (military personnel, press, civilians) were exposed and Vietnam veterans in America successfully fought for monetary recompense for their illnesses. There is an increase in liver cancer and birth defects among exposed Vietnamese.
A Swedish study revealed a ninefold increase in birth defects of children born to dioxin-exposed mothers. Immediately after exposure to the 1976 dioxin cloud in Seveso, Italy, 450 people developed chloracne. A follow-up study showed a higher than normal incidence of spontaneous abortions, loss of sex drive and liver damage. A Belgian study alleges a link between inflammation of the uterus and dioxin emissions from incinerators.
Dioxin was found in the dumping ground at Love Canal, Niagara Falls, USA in 1978 following years of complaints from local people about illness, including cancers. It has become a cordoned-off ghost town.
In 1991, the UK government banned sales of milk from two farms in Derbyshire due to high levels of dioxin. The ban was the outcome of a county surveillance programme in the previous year which had found dioxins in milk and fish which would have given children intakes five times higher than the WHO guidelines. The dioxin was believed to be produced by incineration of chlorine-bleached paper waste. More generally, in 1995 it was reported that aging waste incinerators across Britain were producing levels of dioxins were up to three hundred times the government's safety limits. Surveys suggest that UK breast milk contains one of the highest levels of dioxins in the world.
In 1999, meat exported from Argentina was refused entry into Europe because of dioxins. The dioxins in the meat were understood to have arisen from animal feed.
In 1999, eggs, chicken and other food in Belgium was found to be contaminated with dioxin, due to 80 tons of animal feed made with oil that probably contained PCBs (polychlorinated biphenyls). The level of dioxin in the contaminated chickens was 700 to 1000 picograms per gram of the chicken fat. There is very little or no control of the contents of animal feed in Europe. It was estimated that 124 of the 471 bankruptcies registered in the month of July, three months after the contamination was made public, were linked with the crisis. The European Commission paid 20 billion BEF as compensation for farmers affected by the crisis. It also paid for the destruction of meat and eggs stripped from supermarket shelves or removed from food storages, including 34,000 tonnes of dioxin-tainted pork in Belgium and 30,000 tonnes of the meat abroad.
The Belgian incident released over 6 milligrams of dioxins and 8 litres of PCBs, into chicken feed, which affected the feed for an estimated 16 million chickens for one day.
In 1999 the French ministry of environment estimated that deaths caused by dioxin related cancers affected 1800 to 5200 French people per year.
In the USA, a survey in 1997 by the US Environment Agency found high levels of TCDD (Tetrachlorodibenzo-p-Dioxin), the most toxic type of Dioxin in two grocery stores in New Orleans and in chickens for sale in Mississippi. The dioxin was traced to a betonite clay mine in the area which used the clay as an anti-caking agent in chicken feed. Measurements made by the US Food and Drug Administration found dioxin levels in chickens and eggs at 25 parts per trillion. It is estimated that 1.7 million chickens were affected over several years.
In 1994 farmed catfish popular in the southern states were fed similar feed and up to one third of them were affected with levels up to 43 ppt. The length of time exposed is significant as Dioxins accumulate in body fat.
In Germany after a fall in levels, attributed to tighter smoke stack controls reducing dioxin laden ash falling onto pasture land, levels began to climb once again. research found that the cause originated from imported pulp squeezed from Brazilian citrus fruit used as animal feed. The pulp contained 7ppt dioxins. Similar levels were found in milk. The contamination coming from calcium hydroxide used to neutralise the pulps acidity and thought to have been a waste product from a Belgian chemical company. The EU imports 1.3 million tonnes citrus pulp from Brazil a year for feed and the Brazilians may have been using calcium hydroxide for six years, prior to 1999.
In 1976 an explosion at a chemical plant spewed dioxin over the town of Seveso in Italy. 724 people were evacuated from the worst areas. This group experienced increased incidences of heart disease and several tumours, including those of the lung and liver and non-hodgkin's lymphoma.
TCDD (Tetrachlorodibenzo-p-Dioxin), among the worst known of carcinogens. The highest levels measured, found in workers at herbicide factories in Germany, the Netherlands and the US were linked to increases in all kinds of cancers, depending on the dose of dioxin.
More than 6 kilograms of dioxins are spewed into Europe's air every year by incinerators alone.
Almost all chlorinated products and processes create dioxin somewhere along the way – so to avoid the production of this most toxic of all chlorinated compounds, all chlorine chemistry must be phased out.
Dioxin found in kaolinic clay, sometimes used in animal feed, might be of natural origin.