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Dioxins, furans, Agent Orange, mercury, TCDD, TCDF, TEF
dioxins, furans, Agent Orange, mercury, TCDD, TCDF, TEF

PCBs, Dioxins, Furans and Mercury

--- They Travel Together

dioxins, furans, Agent Orange, mercury, TCDD, TCDF, TEF

Industry representatives argue that some PCB health studies in humans are inconclusive because the victims were exposed to mixtures of PCBs which included traces of dioxins and furans. Sometimes, they point to toxic mercury contamination in our Fox River and Green Bay fish as more important than the PCBs.

But the reality is that local fish eaters are exposed to ALL these chemicals at the same time (plus hundreds of other chemicals), because they’re all present in the fish, sediment, and water of the River and Bay.  We face a much larger total health risk as a result.

dioxins, furans, Agent Orange, mercury, TCDD, TCDF, TEF

Dioxins and Furans are Highly Toxic
Dioxin is considered one of the most toxic man-made chemicals ever made, and furans are about a tenth as toxic. In addition, twelve of the 209 kinds of PCBs are very similar to dioxin in structure and toxicity (about one hundredth as toxic). All three compounds (dioxins, furans and PCBs) are often referred to collectively as "dioxin." They are scored for their dioxin-like potency, and described in terms of their "Toxic Equivalency Factor" (TEF) relative to dioxin. (The other non-dioxin-like PCBs have different toxic properties.)

Dioxin is the well-known toxic chemical which contaminanted Agent Orange -- a defoliant used to clear forests in the Vietnam war -- and caused the evacuation of the town of Times Beach, Missouri, in 1983 and of the Love Canal site in Niagara
Falls, New York, in 1978.

Over the last 30 years, since the end of the 
Vietnam War, serious birth defects have been 
common in Vietnam.  Scientists believe the dioxin 
in Agent Orange is causing the birth defects.

Dioxin has been the subject of an intensive health reassessment by EPA for more than 10 years. Industries originally pushed for the reassessment, but didn’t get the results they expected. Now they’ve spent years lobbying against the release of the study. Currently, the Bush Administration is delaying the release of the final results, but it is widely known that the scientists have determined that dioxins and dioxin-like compounds (such as PCBs) are "known carcinogens." They conclude that the average American may face a 1 in 1,000 risk of cancer due to these compounds, perhaps a risk as high as 1 in 100, because contamination has become so widespread in our general food supply (particularly in meat, dairy, poultry, fish, eggs and other fatty animal products.)

dioxins, furans, Agent Orange, mercury, TCDD, TCDF, TEF

PCBs Were Made With Dioxin and Furan Contaminants

By 1956, or earlier, Monsanto knew that their PCB products could be contaminated with dioxins (TCDD) and dibenzofurans (furans) from the time they were shipped from the factory—a piece of information the company sat on until the late 1960s, when independent researchers discovered this hazard. When PCBs were made, the dioxins and furans were created as byproducts in the mixtures. According to the record of one lawsuit, new PCB oil could be contaminated with dibenzofurans at concentrations of up to 10 parts per million. As the oil ages, according to documents from Monsanto’s files, the concentration becomes considerably higher. Additional references listed below confirm this contamination.

This means that the 7 corporations who dumped PCBs in the Fox River were also likely to dump furans and dioxins at the same time. Both furans and dioxins have been found at significant levels in Fox River sediment and fish.

Unfortunately, many PCB health studies underestimate total health risks in the real world because researchers have used "pure" PCBs without the usual dioxin or furan contaminants. (Monsanto did this deliberately in the 1970s --- see the History section.) 

The structures and components of dioxins, furans and PCBs are very similar.

dioxins, furans, Agent Orange, mercury, TCDD, TCDF, TEF

Heated or Burned PCBs are More Dangerous

The boiling point of PCBs is about 325-366 degrees Centigrade, so PCBs can tolerate fairly high temperatures without exploding or burning. Unfortunately, furans are created from PCBs at 250-450 degrees C, which means that simply heating PCBs can convert them to create additional furans in the mixture. This heat-effect explains how PCBs came to be contaminated in the manufacturing process. 

It’s possible that high-temperature pan frying or grilling of fish or other PCB contaminated foods could convert some of the PCBs to more-toxic dioxins and furans. (The PCBs would also volatilize into the kitchen air at high rates.) The EPA reports that some of the toxic effects of rice-oil PCB poisoning incidents in Taiwan and Japan involved heat conversion of PCBs to furans. (EPA, 1997)

PCBs will burn at higher temperatures, but some of the PCBs will be converted to furans and dioxins, especially in poorly controlled, inconsistent fires. When PCBs are burned at very high temperatures, as in hazardous waste incinerators designed for this purpose, the PCBs may be completely broken down, but as the gases leave the smoke stack they cool and recombine to form new PCBs, furans and dioxins. Municipal waste incineration is the major global source of dioxins.

dioxins, furans, Agent Orange, mercury, TCDD, TCDF, TEF

Oxidation and Additives May Increase Toxicity

Over time, aging PCB mixtures oxidized, especially if exposed to heat or other catalyzing chemicals. PCB oils used in transformers often included chemicals designed to inhibit oxidation of the oils (see Velcon website). Nevertheless, PCBs still degraded. According to the Fluidex/SD Meyers webpage, "As oil ages in a transformer, it oxidizes and begins to break down. Some of the by-products of this degradation are acids, aldehydes and peroxides." This forced the replacement of old PCB oil with fresh oil. It’s likely that Appleton Paper and NCR Corporation also had to account for the aging of their PCB mixtures and they may have included additives to inhibit oxidation. (Some of the research studies on this site indicate that oxidized PCBs also have distinct toxic properties.)

dioxins, furans, Agent Orange, mercury, TCDD, TCDF, TEF

Dioxin-like PCBs Are More Likely to Accumulate in Fish

The higher-chlorinated and dioxin-like PCBs (plus dioxins and furans) are much more likely to be picked up and retained in fish and in the human body, compared to the lower-chlorinated, light-weight PCBs. These dioxin-like compounds are also slower to breakdown. (The lightweight PCBs are more likely to degrade, blow off in the air or stay dissolved in the water and flow north to Upper Green Bay and Lake Michigan.) This means that even in cases where "total PCB" measurements in fish are declining, the more toxic dioxin-like forms could be increasing locally in intensity and health effects in the Fox River and Lower Green Bay. Dioxin-like compounds are strongly linked to cancer.

Many animal studies of PCB toxicity used virgin commercial mixtures of PCBs called by their tradename: "Aroclor." These mixtures were not consistent as to relative amounts of the 209 kinds of individual PCB types. Also, they were usually purified of dioxin or furan contaminants (Monsanto did this deliberately in the 1970s --- see the History section.) This means the researchers were testing a PCB mix very different from the highly toxic mixture that actually accumulates in fish. This could lead to serious underestimates of the true human health effects of PCBs, plus dioxins and furans.

dioxins, furans, Agent Orange, mercury, TCDD, TCDF, TEF

Mercury Levels are High in Fox River Sediments and Fish

If it weren’t for the overwhelming amounts of PCBs in the Fox River, the serious mercury contamination might get more attention. In past years, the pulp and paper industry used mercury compounds as "slimacides" to prevent bacterial or fungal growth on wood stocks and paper pulp. Chlor-alkali production plants were also used in the Fox River Valley to break salt into chlorine and NaOH (caustic soda), which are both used in huge quantities by the paper industry. Mercury was the catalyst in this chemical splitting of salt. As a result, the Fox River became contaminated as the mercury found its way into wastewater discharges to the river. Other important ongoing sources of PCBs include coal-fired power plants and waste incinerators (mercury escapes the pollution controls as a gas).

Mercury is a nerve poison and especially dangerous for unborn and developing babies. As mentioned in the Baby Studies, evidence is building that mercury and PCBs together are much more toxic than either one individually or simply added together. Some of the learning disabilities seen in Great Lakes children studies may be due to the multiplied health effect (synergism) of these chemicals together.

Wisconsin and Michigan anglers who use inland lakes for fishing are being exposed to mercury, and if they also eat fish from the Fox River, Green Bay and Lake Michigan, they’re getting dosed with both toxic chemicals. Fish sold in stores and restaurants are often contaminated with mercury, especially tuna, swordfish and salmon. Mercury is found in the muscle tissue and will not be reduced in a fish fillet by trimming off the fat.

Unfortunately, the U.S. Food and Drug Administration is balking at tightening the human health standards based on more up-to-date science, due to the harm this would cause to the commercial fishing industry and the food industry in general. Numerous agencies are pushing consumers to eat MORE fish with the claim of health benefits, which seems contradictory given widespread fish contamination problems.

The Wisconsin DNR and Wisconsin Division of Health issue a fish-eating advisory which gives information on fish contamination in various lakes and rivers of the state. Visit their online site for details.

dioxins, furans, Agent Orange, mercury, TCDD, TCDF, TEF

Links to More Information

Wisconsin Fish Consumption Advisories
The Dioxin Homepage
The Draft EPA Dioxin Reassessment
EPA’s Mercury Page
Wisconsin Mercury Sourcebook
Mercury Action Alert --- Wisconsin’s Environmental Decade
Mercury in Wisconsin Fish
Mercury Free – What’s In It For Me? (Wisconsin DNR)
Mercury Page for the U.S. Geological Survey
dioxins, furans, Agent Orange, mercury, TCDD, TCDF, TEF


EPA, "Integrated Risk Information System" - Polychlorinated biphenyls (PCBs) CASRN 1336-36-3, (06/01/1997) Quote: "Serious adverse health effects, including liver cancer and skin disorders, have been observed in humans who consumed rice oil contaminated with PCBs in the "Yusho" incident in Japan or the "Yu-Cheng" incident in Taiwan. These effects have been attributed, at least in part, to heating of the PCBs and rice oil, causing formation of chlorinated dibenzofurans, which have the same mode of action as some PCB congeners (ATSDR, 1993; Safe, 1994) Quote: "It is crucial to recognize that commercial PCBs tested in laboratory animals were not subject to prior selective retention of persistent congeners through the food chain (that is, the rats were fed Aroclor mixtures, not environmental mixtures that had been bioaccumulated). Bioaccumulated PCBs appear to be more toxic than commercial PCBs (Aulerich et al., 1986; Hornshaw et al., 1983) and appear to be more persistent in the body (Hovinga et al., 1992). For exposure through the food chain, risks can be higher than those estimated in this assessment." Webpage: http://www.epa.gov/IRIS/subst/0294.htm

EPA. "PCBs: Cancer dose-response assessment and application to environmental mixtures." Quote: "Table 1-1. Typical composition (%) of some commercial PCB mixtures - [at the bottom of the table:] "Impurities include chlorinated dibenzofurans and naphthalenes; see WHO (1993) for sample concentrations." Webpage:

Erickson, M.D., "Analytical Chemistry of PCBs." Butterworth Publishers, Boston, 1991. Dibenzo-furans were found as contaminants in commercial PCB mixtures at part-per-million levels, which varied batch-to-batch. (Per public forum communication from Mark Harkness, GE Engineer)

European Science Foundation. "Workshop on Dioxin Food Contamination, Bayreuth." September 29 - 1 October 2000 Quote: "In January 1999 a storage tank for animal fat in Belgium was badly contaminated with dioxins, furans and PCB. The contamination seems to have been caused by the discharge of about 25 liters of PCB transformer oil into a waste collection unit for animal fats recycled into animals feed." Webpage: http://www.esf.org/update/news/00/dioxin.htm

Fluidex, SD Myers webpage: "As oil ages in a transformer, it oxidizes and begins to break down. Some of the by-products of this degradation are acids, aldehydes and peroxides." Webpage: http://www.sdmyers.com/fluidex/

Francis, Eric. "Conspiracy of Silence: The story of how three corporate giants— Monsanto , GE and Westinghouse—covered their toxic trail." From Sierra magazine, cover story, Sept./Oct. 1994. http://www.planetwaves.net/silence.html

Health Canada [the Canadian version of the EPA], "It's Your Health - Dioxins & Furans." Quote: "Polychlorinated biphenyls (PCBs) used to be an important source of furans, which are contaminants in commercial PCB mixtures." Webpage: http://www.hc-sc.gc.ca/ehp/ehd/catalogue/general/iyh/dioxins.htm

IARC Anonymous. Polychlorinated biphenyls. International Agency for Research on Cancer (IARC) Monographs on the evaluation of the carcinogenic risk of chemicals to humans PG:43-103 YR:1978 IP: VI:18 Quote: "Almost without exception, polychlorinated biphenyls contain various levels of polychlorinated dibenzofurans as contaminants."

Paddock, Todd. "Dioxins and Furans: Where They Come From," Academy of Natural Sciences, Philadelphia, July, 1989. Quote: "Polychlorinated biphenyls (PCBs) have been widely used as cooling fluids in electrical equipment and some industrial cooling systems. Such fluids are often a mixture of PCBs and other chemicals. PCBs can contain low levels of furans, and the other chemicals can contain low levels of both dioxins and furans." Webpage: http://www.acnatsci.org/erd/ea/diox2.html

United Nations. "Persistent Organic Pollutants - Working Group Reports, Working Group Industrial Chemicals and Contaminants" Quote: "Poland: Poland produced PCBs and organochlorine pesticides. PCDDs/Fs were found in transformer oil." [PCDDs/Fs = dioxins & furans] Webpage: http://www.chem.unep.ch/pops/POPs_Inc/proceedings/slovenia/KWG.html

Velcon, describing their SuperDri Cartridges for removing water from transformer oils: "Will not remove oxidation inhibitors." Webpage: http://www.velcon.com/superdri.htm

dioxins, furans, Agent Orange, mercury, TCDD, TCDF, TEF
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dioxins, furans, Agent Orange, mercury, TCDD, TCDF, TEF