TL: DIOXINS, FURANS AND PCB'S - THE TRUE STORY SO: Renate Kroesa, M.Sc., Greenpeace International (GP) DT: November 1989 Keywords: toxics dioxins furans pcbs factsheets gp introduction / DIOXINS, FURANS AND PCB's - THE TRUE STORY Dioxins, furans and PCB's have become some of the most controver- sial chemicals of modern society. Dioxin in particular has been labelled the most toxic chemical ever produced by man. More than $1 billion has been spent so far on dioxin research (1), yet at the same time, industry and government officials insist that not enough evidence on the toxicity exists to justify elimi- nation of the sources. This factsheet explores some of the myths and facts surrounding these environmentally dangerous chemicals and explains why the scientific debate has become of an increasing political nature. WHAT ARE 'DIOXINS' The term 'dioxins' usually refers to a whole chemical family with 75 individual members, which more correctly should be termed chlorinated dibenzo-p-dioxins. The most toxic member of this family is 2,3,7,8-Tetra-Chloro-Dibenzo-p-Dioxin, often abbrevi- ated as 2,3,7,8-TCDD. Often, the term 'dioxins' also includes a closely related chemi- cal family called chlorinated dibenzofurans. The most toxic among the 135 known furans is 2,3,7,8-Tetra-Chloro-Dibenzo-Furan (TCDF), which is one tenth as toxic as the corresponding dioxin, TCDD. Of the 210 dioxins and furans, twelve are extremely toxic and are commonly referred to as the 'Dirty Dozen'. Their individual toxi- city is ranked by comparing them to 2,3,7,8-TCDD via internatio- nally agreed upon Toxic Equivalence Factors (TEFs). Box 1 shows the chemical structures of dioxins and furans, and their toxicity ranking. PCB's are another chemical family closely related to dioxins. Due to their similar chemical structure, some PCB's can act through exactly the same pathways in organisms as dioxins, but are much less potent. However, due to their chemical nature, PCB's are inevitably contaminated with furans and dioxins, and will form these more toxic chemicals during fires. [Greenbase Inventory March 1990 ] *Source: Renate Kroesa, M.Sc., Greenpeace, November 1989 Keywords: toxics dioxins furans pcbs factsheets gp introduction toxicity bioaccumulation sublethal ## HOW TOXIC ARE DIOXINS(2) a) Extreme Ability to Kill Dioxin TCDD is the most toxic man-made chemical ever tested on laboratory animals. Acutely lethal doses are measured in micro grams per kilogram animal weight, the parts per billion range. (2e) Though the lethal dose varies considerably from species to species, dioxin has been found to be extraordinarily toxic to all species tested. Characteristic of lethal dioxin exposure is the 'wasting syn drome': animals seem to waste away, and eventually die, without displaying any overt pathological symptoms. The exact reason why dioxin can cause death in these minute quantities is not yet known.(2e) b) Extremely Bio-Accumulative Dioxins are some of the most persistent and bio-accumulative man- made chemicals released into the environment. While dioxins can be broken down under certain conditions, in particular when exposed to intensive sunlight, they cannot be broken down once absorbed by soil or dust. When they enter the food-chain, they will bio-magnify, often to levels many thousands of times higher than their surroundings.(2d,3) It is this combination of dioxin's extreme toxicity and its bio- magnification in the environment that makes Greenpeace believe that there can be no safe level of dioxin emissions. c) Long-Term Toxicity - the Dioxin-Receptor More worrisome than the high acute toxicity are the more insi dious long-term effects of exposure to sub-lethal doses of dioxin. Daily doses 1,000 times below the lethal dose, the parts per trillion range, cause profound delayed effects in mammals, such as cancer, damage to the immune system, and reproductive failure.(2e) Concentrations in water another 1,000 times lower, the parts per quadrillion range, can still cause a wide variety of toxic effects in fish, e.g. in rainbow trout.(3) Scientists believe that the reason why dioxin is so toxic in minute quantities lies in its mode-of-action inside the cell. Dioxin imitates natural steroid hormones (e.g. estrogen) in our bodies. Dioxin fits into a protein receptor, which normally responds to these steroid hormones. The receptor then transports the dioxin directly into the cell nucleus, where it interacts with basic cell chemistry.(2a) The 'dioxin-receptor' has been identified in laboratory animals as well as in humans. One can compare this mode-of-action with dioxin acting as a key to the receptor-lock. Some individual dioxins and furans fit better into the receptor than others; PCB's do not fit as well. 2,3,7,8-TCDD fits best into this recep tor and consequently is the most toxic. d) Chloracne The disfiguring skin disease chloracne is often erroneously referred to as the only human health effect positively linked to dioxin exposure, and is often down-played in its severity. Yet, chloracne is always accompanied by other health effects, such as chronic weakness in the legs, severe pain in the joints, headaches, pronounced fatigue and irritability, and often lasts for decades, as several studies on occupationally exposed workers show.(2b) e) Cancer 2,3,7,8-TCDD is the most potent carcinogen tested to date.(2) Researchers so far have been unable to clarify whether dioxin acts as a co-carcinogen or whether it suppresses the immune response to other carcinogens. Yet given the fact that other carcinogens are plentiful in our polluted environment, that question can be of academic interest only. [Greenbase Inventory March 1990 ] *Source: Renate Kroesa, M.Sc., Greenpeace, November 1989 Keywords: toxics dioxins furans pcbs factsheets gp introduction reproductive effects human health workers ## f) Reproductive Effects More subtle than chloracne or cancer are other health effects such as reproductive failure. It is striking that reproductive failure has been observed in all animal species tested, be it fish, bird or mammal. It is therefore highly likely that repro- ductive failure also occurs in humans exposed to dioxin.(2c) Most disturbing are laboratory experiments on primates such as rhesus monkeys, whose reproductive systems were found to be extremely sensitive to dioxins when administered in minute doses on a daily basis. Researchers found a serious decrease in sperm count in exposed males, and an inability to conceive or carry the pregnancy to term in exposed females.(2d,6) Some evidence of such reproductive failure in humans already exists. Jock Ferguson, a Canadian reporter who investigated health effects in occupationally exposed workers, once interviewed three Hooker Chemicals workers, all of whom suddenly came to realize that none had fathered children.(7) Why is it that incidences like these are always dismissed immediately as anecdotal evidence, and are not followed up in a formal investigation, e.g. an epidemiological study, whereas negative findings are always promoted as certainty? Other reproductive effects observed in laboratory animals include stillbirths and birth defects. Dioxin has been linked to spina bifida, anencephaly (absence of brain) and cleft palate.(2) [Greenbase Inventory March 1990 ] *Source: Renate Kroesa, M.Sc., Greenpeace, November 1989 Keywords: toxics dioxins furans pcbs factsheets gp introduction politics solutions hhcs chlorine production business ## THE POLITICS - WHOSE INTERESTS ARE AT STAKE? Obviously, when the entire organohalogen production is being questioned, some very powerful interest groups want to have a say. Much is at stake, both in terms of liability law suits and lost profits. It would be naive to think that the chlorine- and organochlorine- producing industry, e.g. PVC and chlorinated solvents or pesti cide producers, have had no influence on the colour of dioxin science. Other vested parties to name include the incineration lobby, the pulp and paper industry and the metallurgical indus try. Even defense departments are involved in the discussion, due to the use of Agent Orange in Vietnam and elsewhere. The result: instead of devoting research efforts toward elimina ting the sources, finding alternative products or production technologies, and safe methods of dealing with the existing wastes, the public is being deluged with attempts to linguisti cally detoxify dioxin, via media releases, information brochures and widely publicized risk assessments. Risk assessments, in particular, can at best only be viewed as pseudo-scientific exercises, because they do not take into account: * total exposure from all possible sources * synergistic effects * effects on the next generation, for example through contaminated human milk * all possible health effects, rather than selected health effects only, e.g. certain forms of cancer. [Greenbase Inventory March 1990 ] *Source: Renate Kroesa, M.Sc., Greenpeace, November 1989 Keywords: toxics dioxins furans pcbs factsheets gp introduction bibliography ## REFERENCES 1) Report from Conferences, the 5th Int'l Dioxin Symposium, Bayreuth, 1985; Chemosphere, 1986, 15, N1-2 2) This entire section is based on the following five overview reports/books published on the toxicology of dioxin. All reports/books give an excellent overview and provide many detailed references to the interested reader. a) 'Human Health Aspects of Exposure to PCDDs and PCDFs'; UAREP, Bethesda, Maryland, June 1988 (funded by the American Paper Institute). b) 'The Chemical Scythe', by Alistair Hay; Plenum Press 1982 c) 'A Cancer Risk-Specific Dose Estimate for 2,3,7,8-TCDD'; US-EPA/600/6-88/007Ab, June 1988, plus Appendices A-F d) 'Dioxins in the Environment' by the UK Dept of the Envi ronment; Pollution Paper No. 27, 1989 e) S.A. Skene et al, Human Toxicol, 1989, 8, 173-203 3) P.M. Mehrle et al, Environmental Toxicology and Chemistry, 1988, 7, 47-62 4) F. Rohleder, Presentation to the 9th Int'l Dioxin Symposium, Toronto, 1989 5) (T. Sinks, Presentation to the 7th Int'l Symposium on Epide miology in Occupational Health, Tokyo, 1989) 6) a) R.E. Bowman et al, Neurotoxicology, 1986, 7, 637-650 b) J.R. Allen et al, Toxicology and Applied Pharmacology, 1979, 48, A180 c) J.R. Allen et al, Bulletin of Environmental Contamination and Toxicology, 1979, 21, 463-469 7) 'Who do you believe?', Jock Ferguson; Chemosphere, 1985, 14 791-796 8) PCBs, PCDDs and PCDFs in Breast Milk: Assessment of Health Risks; WHO, Regional Office for Europe; EH 29 (1988) 9) W.R. Swain; Aquatic Toxicology, 1988, 11, 357-377 10) Monitor 1988, Sweden's Marine Environment - Ecosystems Under Pressure; National Swedish Environmental Protection Board 11) a) R.R. Bumb et al (Dow Chemical), Science, 1980, 210, 385 b) Nestrick et al (Dow Chemical), Chemosphere, 1983, 12, 617- 626 12) J.M. Czuczwa, R.A. Hites, Chemosphere, 1986, 15, 1417-1420 13) a) A. Schector et al, Chemosphere, 1988, 17, 627 b) A. Schector et al, poster at the 9th Int'l Dioxin Symposium, Toronto, 1989 14) W.V. Ligon et al (General Electric), Environ. Sci. Technol. 1989, 23, 1286-1290 15) Report of the Joint Health and Welfare Canada/Environment Canada Advisory Committee on Dioxins, November 1983 [Greenbase Inventory March 1990 ] *Source: Renate Kroesa, M.Sc., Greenpeace, November 1989 Keywords: toxics dioxins furans pcbs factsheets gp introduction solutions plans research sources incineration ## THE SOURCES AND ELIMINATION STRATEGIES While the production of PCB's was finally outlawed worldwide, and the worry now is how to eliminate existing PCB wastes, dioxins and furans seem to come from many different and ongoing sources. Yet there is an obvious common denominator to these sources: modern society's use of chlorine. It is often claimed that dioxin is a naturally occurring toxin, produced in forest fires and wood stoves. This theory, first introduced by Dow Chemical scientists as the 'Trace Chemistry of Fire' theory(11), has been convincingly disclaimed by at least three separate studies: a) the Czuczwa study, which investigated contamination of Great Lakes sediments, found that dioxin levels were virtually non- existent prior to the Second World War, which coincides with the beginning of large-scale production and combustion of organochlo rines.(12) b) the Inuit mummy study, in which A. Schector investigated tissue of two 400-year-old mummies. Only minor amounts of the less toxic but very persistent octa-chlorodibenzo-p-dioxin (OCDD) were found.(13) c) the Chilean mummy study, in which W.V. Lignon analyzed tissue of nine Chilean mummies for dioxins and furans. Again, only minor amounts of OCDD were found.(14) All three studies conclude that rising dioxin levels are intima tely linked to modern industrialized society. Box 3 lists strate gies to eliminate major industrial sources of dioxin, all of which are connected with the use of elemental chlorine as well as the production and combustion of chlorinated organic chemicals (organochlorines). -------------- Box 3: SOURCE ELIMINATION STRATEGY a) PRODUCTION OF ORGANOCHLORINES, e.g. * chlorophenols and ban production and use chlorobenzenes immediately b) COMBUSTION OF ORGANOCHLORINES, e.g. * car exhaust, leaded gas don't add org.chlorine scavengers (use unleaded gas) * municipal waste incinerators comprehensive recycling * haz.waste incinerators waste reduction/elimination and use other destruction methods * copper reclamation eliminate PVC coating * steel recycling no chlorinated rubber/plastics to be used in car or machinery c) USE OF CHLORINE GAS, e.g. * pulp and paper industry less bleaching and bleaching with oxygen/H2O2 * zinc/magnesium smelters use chlorine-free process --------------------- Elemental chlorine does not exist in Nature, and Nature does not produce organochlorines on a large scale either, with the excep tion of some very simple molecules, such as methylchloride or dichloromethane. Many of the industrial dioxin sources are easy to eliminate: Chlorophenols, for example, are already banned in many European countries. Sweden actually experienced a decline of dioxin levels in human milk after banning both pentachlorophenol and chloro phenol-based herbicides. Both Canada and the United States actively resist such a ban, and chlorophenols are still used for wood preservation (utility poles and railway ties) and as a fungicide on lumber destined for export. Once treated, these wood articles become very significant sources of dioxin when burnt in wood stoves or incinerators. Municipal incinerators are another very significant but completely avoidable source of dioxins. They not only generate vast amounts of dioxin-laden ash but also emit dioxins into the atmosphere where they can be transported over long distances, e.g. to the Arctic. The disposal of toxic incinerator ash has become a highly publicized problem since export schemes to Panama and other developing nations were exposed by Greenpeace. Incinerators should be eliminated for other environmental reasons as well. Incinerators are not compatible with recycling systems, since comprehensive recycling systems eliminate cheap fuel from the waste stream, e.g. paper or plastics, thus eliminating the economic viability of incinerators. Copper reclamation plants and hospital waste incinerators are also major dioxin sources due to the burning of PVC (polyvinyl chloride) and PVDC (polyvinylidene-chloride) waste. Copper wires are coated with PVC, and many hospital disposable items are made of these chlorinated plastics, as are many disposable household products. Many W-German cities, e.g. Bielefeld, Munich, Aachen and others, have now banned the use of PVC material in public buildings to protect the public and fire fighters from dioxin formed during fires. The Danish government is actively pursuing a phase-out of all PVC articles, and is presently researching a feasible time- table. The Swedish government is pushing for a phase-out of chlorinated solvents, due to the risks they pose to ground water supply, their effects in the lower atmosphere, and the associated waste disposal problems. The pulp and paper industry as well as certain branches of the metallurgical industry are significant sources of dioxin due to the use of raw chlorine. Chlorine gas reacts with wood compounds or carbon electrodes to form dioxins. European governments are researching and implementing new production processes that would the use of chlorine and thus the generation of dioxin as well as other toxic organochlorines. It is clear that eliminating these sources of dioxin means elimi nating a much larger portion of toxic chemicals from our environ ment. This makes a lot of sense from an environmental point of view, because dioxins never come alone, but are always accompa nied by other toxic organochlorines. Dioxin indeed is only the tip of an iceberg of environmentally dangerous organochlorines and other organohalogens; and success fully eliminating modern society's dioxin sources will inevitably mean eliminating this iceberg, which is exactly the reason envi ronmentalists are becoming more and more vocal in this matter. To Greenpeace, dioxin is a symbol of whether we want to deal with our pollution or whether we want to continue our self-destructive lifestyle. [Greenbase Inventory March 1990 ]