• Isn't chloracne the only evidence of dioxin exposure?
• Are dioxins produced naturally in the environment?
• Aren't there many different sources of dioxin? Why blame the chlorine industry?
• In some countries, dioxin levels are falling in the environment and in human breast milk which shows we now have better control over emissions. Why still call for a phase out of chlorine production?
• Can I lower my exposure to dioxin?
• How are natural estrogens in our food different from synthetic estrogens?

   

A: Public concern about effects of dioxin on human health was heightened in 1976 following an accident at Seveso in Italy, when an explosion at a chemical factory caused the release of high levels of TCDD (dioxin). The most commonly reported effects on humans following this accident and other incidents of high dioxin exposure was a skin rash called chloracne.

Since then numerous animal experiments and several epidemiological studies in humans have shown that dioxin causes a wide range of health effects. New data from Seveso found increased deaths from digestive cancer among women in Seveso who lived closest to the area that was highly contaminated with dioxin. In a 15-year follow-up study reported in the November 1997 issue of the journal Epidemiology, Pier Alberto Bertazzi, University of Milan, and co-authors found that men in the most highly contaminated site had increased mortality from rectal cancer.

In February 1997 the International Agency for Research on Cancer, a part of the World Health Organisation, classified TCDD as a Class 1 Human Carcinogen.

It is now recognised that exposure to even minute doses poses damage to health other than cancer. The United States Environmental Protection Agency (EPA) has conducted a reassessment of the environmental and human health risks from exposure to dioxin. It is expected to conclude that exposure to dioxin poses a large scale, long term threat to public health and the environment -- due not only to increased cancers but also because of possible birth defects, reproductive problems, nervous and brain disorders and damage to immune systems.

A. After an extremely extensive review, the U.S. Environmental Protection Agency (EPA) estimates that 98 percent of dioxins in the environment arise from human activities.(1) As shown by the historical record of lake sediment cores in the U.S., dioxins and furans were almost undetectable until around 1940. Over the following 30 years, their concentrations increased in parallel with increasing commercial production of organochlorines.(2) Likewise, in archived British soils, concentrations of dioxins and furans were extremely low during the mid-1880s, then began a steady increase around the turn of the century, (3) when mass production of elemental chlorine began in the U.K.(4) The increased use of coal during the industrial revolution was also not responsible: Studies of atmospheric emission from coal-burning power plants did not detect any PCDD/Fs (5)

Analyses of ancient human tissues also show that, if dioxins are produced in nature, the quantity produced is minuscule in comparison to that produced through human activities. Mummified remains of nine Chilean Indians dating from some 2800 years ago were found to carry no detectable concentrations of dioxins, with the exception of octachlorodibenzo-p-dioxin, which was present at concentrations more than 20 times lower than the lowest values found in people from modern industrialized countries.(6) Similar results were obtained from the tissues of Eskimos who died and were frozen years ago.(7,8)

A. The production of dioxin is inherently linked to chlorine chemistry which is why the chlorine industry attempts to divert responsibility away from its products and processes.

In 1980 the Dow Chemical Corporation published a theory called the "Trace Chemistries of Fire." This was predicated because in the late 1970's, attention turned to dioxin pollution because of the spraying of chlorinated herbicides and the effects of dioxin on Vietnam veterans exposed to it as a contaminant in the herbicide Agent Orange. Producers of chlorinated herbicides faced the possibility of restrictions on their products and massive class-action claims for health effects among exposed veterans. At the height of this activity, Dow Chemical, who had been the largest producer of Agent Orange, published a novel theory in the prominent scientific magazine Science. Dioxin, Dow said, is a natural chemical, occurring in any and all combustion processes, including forest fires, volcanoes, and household stoves.[1] Dow's conclusion: dioxin is not a pollutant uniquely associated with the modern chemical industry but has in fact been with us "since the advent of fire."[2]

In support of this "Trace Chemistries of Fire" theory, Dow's scientists cited data that dioxins are ubiquitous in soils, sediments and the residues from many types of incinerators, including those at its own chemical plants. Perhaps, Dow suggested, dioxin is formed from the presence of salt -- which is everywhere -- in any type of fire. Dow's implication was that "natural sources" were and always had been more important dioxin sources than the chemical industry.

To this day, Dow and its allies repeat the claim of "natural dioxin." Responding to concern raised by EPA's 1995 dioxin reassessment, for instance, the Chlorine Chemistry Council emphasized the importance of volcanoes and forest fires as dioxin sources. A lengthy technical report prepared for the Chlorine Chemistry Council (CCC) by the American Society of Mechanical Engineers, purported to find that dioxin is formed in any and all combustion devices irrespective of the presence of chlorinated chemical products.[3]

A study by Dow in Europe argued that there was no relationship between dioxin emissions from a German trash incinerator and the feed of chlorinated wastes to the facility. [4]

CCC submitted both documents to EPA as continuing proof of the "trace chemistries of fire" theory.

This was repeated again in a 1994 Chlorine Chemistry Council and Chemical Manufacturers’ Association report "Dioxin Reassessment Briefing Packet" dioxins are produced naturally and therefore found everywhere in the environment. They state: "Among the natural sources of dioxin are forest fires, Volcanoes, and compost piles. Man-made sources of dioxin include municipal, hospital and hazardous waste incinerators, motor vehicles, residential wood burning and a variety of chemical manufacturing processes. With so many sources, it is not surprising that scientists have detected dioxins virtually everywhere they have looked. "

Dioxin synthesis requires four things:

1. A source of chlorine (or bromine);
2. Organic matter;
3. A thermally or chemically reactive environment in which these materials can combine;
4. A source of oxygen.

The production of dioxin is inherently linked to chlorine chemistry. Because organic matter is ubiquitous and reactive environments (such as fires and industrial processes) are common, it is the presence of available chlorine that is the unique and preventable factor in dioxin generation. It is only because chlorine chemistry and its products have become so widespread that dioxin formation appears to be ubiquitous.

The major dioxin sources are those central to chlorine chemistry. For instance, pulp and paper mills form and release dioxin when they use chlorine gas and other chlorinated chemicals to bleach wood pulp white. Dioxin is formed in chemical plants when a wide range of chlorinated organic chemicals are manufactured -- including pesticides, solvents, chemical intermediates, and feedstocks for the plastic polyvinyl chloride (PVC). Dioxin has even been identified at the root of chlorine chemistry: in the sludges and residues from the chlor-alkali process, in which chlorine gas is produced by passing a powerful electric current through salt-water.[5,6]

Even for those sources not obviously related to the chlorine industry, the presence of available chlorine turns otherwise dioxin-free processes into dioxin sources.

For instance:

• Automobiles are sources of dioxin because chlorinated chemicals are deliberately added to fuels; vehicles burning chlorine-free fuels do not emit dioxins.[7]
• Steel mills emit dioxin because chlorinated solvents, cutting oils and plastics are introduced into these high-temperature furnaces.[8]
• Recycling smelters for copper, lead, and steel are major dioxin sources because the products recycled in them contain significant quantities of PVC (cable coatings, battery casings, automobile components, and so on)[9].
• Dioxin is found at sawmills because of the use pentachlorophenol as a wood preservative[10]

Dioxin is ubiquitous, but only because chlorine chemistry itself has become ubiquitous in the last 50 years.

What about the largest dioxin sources, incinerators? Incinerators are a major dioxin source because they burn huge quantities of chlorine-containing wastes.

• Hospital waste incinerators burn huge quantities of PVC plastic -- which accounts for almost 10 percent of all medical waste.[11]
• Trash incinerators generate dioxin because of the presence of disposable PVC plastic products, which accounts for about 80 percent or more of the organically-bound chlorine in the waste stream; chlorine-bleached paper and chlorine-containing household chemicals like paints, pesticides, and cleaners provide the remainder.[12]
• Hazardous waste incinerators emit dioxin because they burn chlorinated solvents or copious wastes from the manufacture of chlorinated plastics, pesticides, and other chemicals.

A host of studies indicate a clear relationship between the burning of chlorinated organic chemical products and wastes, especially PVC, and dioxin emissions from combustion facilities.[13,14,15,16,17,18,19,20]

Similarly, dioxin released from forest fires and wood burning are probably due to contamination of the wood by phenoxyherbicides[16]) or from resuspended material from aerial deposits[18]

A. The decrease in dioxin levels in some countries probably reflects the reduction of some organochlorine pesticides and the shutting down of the worst incinerators. Such effects are notably seen in Germany and the UK. However such decreases do not pertain globally. The chlorine industry is expanding in other areas of the world thus increasing the amount of chlorinated wastes and products which eventually have to be disposed of. It is now known that dioxins and other persistent organic pollutants (POPS) are carried on global air currents and distill out in colder latitudes. An increase in production elsewhere affects us all.

There is no safe dose of dioxin exposure and children are at most risk. End of pipe pollution control cannot solve the problem of eventual release into the environment. Better incinerator design, for example, simply reduces atmospheric emissions and diverts the dioxins generated in the combustion process into contaminated ash residues or aqueous discharges. In effect, the total quantity of dioxins and furans generated by these incinerators is more than six times greater than the amount they release into the air. Currently defined best available techniques such as modern carbon injection systems do not prevent the formation of dioxins.

These residues are then landfilled or, in some countries, like the Netherlands are used in road construction. Dioxin is highly persistent, however, and will eventually leak into the environment where it presents itself for ingestion by animals and thereby intensifies up the food chain.

Even if the chlorine industry could achieve better efficiency in their production processes, such as cleaner PVC manufacturing plants, it is impossible to achieve zero emissions of dioxins and dioxin-like compounds. For instance, highly chlorinated wastes are always produced during PVC plastic manufacturing presenting risks to workers and communities. All products of the chlorine industry, particularly PVC plastic, can be a major dioxin source if accidentally burned in building fires or in smoldering landfills.

Eventually chlorinated products come to the end of their lifecycle and have to be disposed of. For this reason the chlorine industry avidly supports incineration which brings us full-circle to the fact that incineration cannot destroy dioxins and other dioxin-like compounds. It is wiser to simply substitute non-chlorinated processes and products and move to safer materials.

A. All industrialized populations carry body burdens of dioxins even vegetarians and vegans who eat lowest on the food chain. Consumption of organic and less contaminated food sources, will of course, lessen body burden levels. However this is not a solution. Dioxins are persistent with a half life in the human body of approximately 7 years. This means that 50% of dioxin levels will remain after seven years assuming no new inputs whatsoever – an impossibility concerning the global nature and movement of persistent organic compounds. All evidence now suggests there is no safe dose of dioxin exposure and that timing of exposure – particularly to the developing fetus – may be more important than the quantity of dose. Furthermore, many indigenous human populations, such as the Arctic Inuit, rely on wild food that continues to be seriously contaminated via long-range transport of persistent organic pollutants. Other species and their young, particularly wildlife high on the food web such as marine mammals, have no protection from environmental contaminants. We have always been an integral part of our global environment. The continued expansion of toxic industries affects us all.

A. There are major differences between phytoestrogens and man-made endocrine-disrupting chemicals. Phytoestrogens are readily broken down and excreted from the body. Consequently they spend very little time inside the body. The situation with man-made chemicals is different. Humans and animals have not evolved alongside vast quantities of man-made endocrine-disrupting chemicals in the environment. Unlike phytoestrogens, many are persistent and cannot be broken down or detoxified. These may bioaccumulate in body fat, remaining in the body for long periods of time

About 300 different plants are known to produce and contain a number of natural chemicals called phytoestrogens. These are thought to serve a variety of functions, acting as natural fungicides, regulating plant hormones, deterring herbivores from eating them and as a protection against ultraviolet radiation from the sun. Plants that contain phytoestrogens include many in our diet, such as whole cereal grains, seeds, soy, cabbage, beet, broccoli and peas. When some phytoestrogens are eaten, they are broken down in the gut to form estrogen-like compounds, which are able to bind to estrogen receptors. Phytoestrogens spend relatively little time in the body before being excreted.

Eating a variety of plants in a normal diet does not seem to affect human fertility and may in fact be beneficial. The most likely explanation is that, as humans and animals have evolved alongside plants, any harmful effects on fertility that a normal diet may cause, may have been selectively bred out of the populations long ago.