Forget obesity, here is a true culprit

Story last updated at 7:14 a.m. Saturday, June 5, 2004

Study indicates computers pose ‘toxic dust’ health risk
BY RACHEL KONRAD
Associated Press

SAN FRANCISCO—“Toxic dust” found on computer processors and monitors contains chemicals linked to reproductive and neurological disorders, according to a new study by several environmental groups.

The survey, released Thursday by Silicon Valley Toxics Coalition, Computer TakeBack Campaign and Clean Production Action, is among the first to identify brominated flame retardants on the surfaces of common devices in homes and offices.

Electronics companies began using polybrominated diphenyl and other flame retardants in the 1970s, arguing that the toxins prevent fires and cannot escape from plastic casings.

“This will be a great surprise to everyone who uses a computer,” said Ted Smith, director of the Toxics Coalition. “The chemical industry is subjecting us all to what amounts to chemical trespass by putting these substances into use in commerce. They continue to use their chemicals in ways that are affecting humans and other species.”

Researchers collected samples of dust from dozens of computers in eight states, including university computer labs in New York, Michigan and Texas, legislative offices in California and an interactive computer display at a children’s museum in Maine. They tested for three types of brominated flame retardants suspected to be hazardous.

The most toxic piece of equipment discovered by the researchers was a new flat-screen monitor at a university in New York, implying that newer equipment isn’t necessarily cleaner.

Penta- and octa-brominated diphenyl will be taken off the market by the end of the year. Environmental groups are demanding legislation that would ban deca-brominated diphenyl, too.

PBDEs, which have caused neurological damage in laboratory rats in numerous studies, are related to polychlorinated biphenyls.

PCBs have been used in fire extinguishers, fluorescent lights and liquid insulators since the 1920s. They were outlawed in the 1970s, but the toxins don’t break down, and they still are found in the vironment.

The Agency for Toxic Substances and Disease Registry, part of the U.S. Department of Health and Human Services, and several other organizations have confirmed that PCBs damage brains of human fetuses.

Scientists have not directly correlated exposure to PBDEs with specific diseases or developmental impairment. Researchers at the University of California-Davis and elsewhere are studying possible links between brominated flame retardants and autism, but results are years away.

Independent researchers who reviewed the new study say consumers shouldn’t throw out their computers, and they needn’t wear special gloves or minimize exposure to computer monitors. There’s no known way to remove dust-born PBDEs, so special wipes or sprays wouldn’t reduce chemical exposure.

“The levels in the dust are enough to raise a red flag but not enough to create a crisis,” said Dr. Gina Solomon, senior scientist at the Natural Resources Defense Council and assistant professor of medicine at the University of California-San Francisco. “I have an old computer monitor in front of me now, and I’m not about to throw it away. But when I get a new one, it darn well will be free of these chemicals.”

The electronics industry has been reducing or eliminating some brominated flame retardants since the late 1990s, when European countries began prohibiting the sale of products that contain the chemicals.

Dell Inc. and many other computer makers continue using a flame retardant related to PBDEs on circuit boards. They use lead, mercury and other toxins in central processing units and monitors. But Dell, along with Apple Computer Inc. and others, stopped using PBDEs in 2002.

“People can be very confident about their new computer purchase,” said Dell spokesman Bryant Hilton. “We’ve worked a lot with suppliers, and we require audits and material data sheets on all our products. It’s an important topic to be aware of, and brominated flame retardants are something we’ve been very focused on and will continue to be focused on.”

Thanks for posting Dad

http://www.theglobeandmail.com/servlet/story/RTGAM.20040607.wxtoxicgt07/BNStory/Front/

The breast milk of Canadian women contains the second-highest levels in the world of a compound used as a flame retardant in computer casings and household furniture, according to a new survey compiled by Health Canada.

The highest amounts of the contaminants, known as polybrominated diphenyl ethers, or PBDEs, were detected in the milk of nursing U.S.
mothers.

But women in Canada had levels about five to 10 times those in other advanced industrial countries, such as Japan, Sweden, and Germany.

The amounts in U.S. women were double those in Canada, and
exceptionally high compared to those elsewhere in the world.

The international comparison was made by Jake Ryan, a research scientist at Health Canada, who is presenting the finding later today at a
conference in Toronto devoted to the controversial chemicals, which
some scientists fear may be as dangerous as the polychlorinated biphenyls, or PCBs, that were banned as an environmental hazard in the 1970s.

Health Canada official Samuel Ben Rejeb said the department is studying why levels in Canadian women are so much higher than elsewhere in the
world.

Health Canada and Environment Canada recommended last month that some forms of PBDEs be declared toxic and eliminated from use. The European Union has already issued restrictions on the substances, and several U.S. states plan to follow suit.

“This is a poster-child chemical for something that ought to be zeroed out,” says Tom Muir, a researcher at Environment Canada who has studied PBDEs and is worried they may be contributing to thyroid disorders and children’s health problems.

Although the federal government is proposing restrictions on PBDEs, Health Canada concluded that human exposure from sources such as breast milk had not yet reached harmful levels.

But Mr. Muir said PBDE levels in the breast milk of a small number of
women surveyed in North America are approaching the critical
concentrations associated with health impairment from PCBs.

The highest reading in Canada was of one woman who had 956 parts per
billion of PBDEs in the fat of her breast milk.

The highest in the U.S. was just over 1,000 ppb. The average breastfeeding woman in Canada has concentrations of about 60 ppb. Samples were taken in all regions of Canada.

PCB concentrations become of concern when they reach 1,250 ppb,
according to Mr. Muir.

Health Canada said confidentiality reasons prevented it from seeking clues on why concentrations seem to vary so wildly.

Mr. Ryan based his findings on a survey of almost all of the studies in the world that have analyzed mothers’ milk for the chemical. Scientists have checked milk samples from Sweden and Japan dating back to the early 1970s, finding almost no PBDEs.

But over the past three decades, increasing amounts of PBDEs have been added to consumer products such as TV sets, computers, and the
polyurethane foam used in furniture to make them less likely to burn during a fire.

Levels in human milk have been rising in tandem with the growing use of the product, and in Canada are now four times those in the early 1990s.

International comparisons made by Mr. Ryan indicate that breast milk has about 100 times more PBDEs than samples collected 30 years ago.

Health Canada has been studying the chemical because of fears it is a new pollutant in the food supply.

“We were interested in PBDEs as a new emerging class of persistent organic pollutant,” said Mr. Ben Rejeb, who is associate director of Health Canada’s bureau of chemical safety.

He said that while levels of most other harmful industrial chemicals found in breast milk, such as DDT, PCBs, and dioxin, have been falling in recent surveys, PBDE concentrations have risen rapidly.

“This is unlike the other persistent organic pollutants.”

Health Canada denied a request from The Globe and Mail to interview Mr.
Ryan about his findings, but had Mr. Ben Rejeb answer questions about his colleague’s work.

It is not known exactly how PBDEs migrate from consumer products into human tissue. They have been found in household dust and sewage ludge, in many fatty foods such as meat and fish, and in wildlife.

Although there is little research on human health and PBDEs, recent
animal experiments with the chemical have linked it to learning difficulties, memory impairment, and alterations in thyroid hormone levels.

The similarity of these effects to those of childhood attention-deficit disorders, and the rising tide of adult thyroid problems, have led to calls for studies into whether PBDEs and other pollutants play a role
in these ailments.

Mr. Ben Rejeb said Health Canada has been checking PBDE levels in food to see if there is a link to the breast-milk findings.

The department has found the contaminant is present at about the same
levels in Canadian and European food, suggesting the high Canadian readings in breast milk are due to some other source.

Because they’re in computers and furniture, PBDEs are probably found in large numbers of homes and offices.

But they are also present in many manufacturing companies and recycling centres that deal with high-technology waste. “It would have to be related to the use of PBDEs,” Mr. Ben Rejeb said.

The troll’s pseudo-science is as nutty as usual. Milk from any one species, human or other, contains pretty much the same fat content no matter what weight the mother is.

As far as toxins, the issue is *concentration*, ie amount of toxin *per* unit of milk output; since this is a division (amount of toxin)/(amount of fat), a person of 80 pounds can have the same *concentration* as a person of 200.

The fact that the US and Canada have the highest *concentrations* in the world of these chemicals has obvious connections to the general North American lifestyle, with lots and lots of plastic and foam rubber products. People who live a traditional lifestyle with natural materials in a remote location without these products will *usually* have a lower concentration.

There is however one further complication and warning sign; Inuit women in the Arctic have been found to have a very high concentration of PCB’s. It is generally believed that the problem is that these chemicals do not break down easily in the environment. The chemicals were poured into the water and then get into fish which are eaten by other fish which are eaten by seals which are eaten by people and by polar bears. Each level of consumption concentrates the harmful chemicals so top predators such as humans and polar bears in the far north are in real danger.

The notable thing in this report is that people in the same area had widely varying toxin concentrations. This suggests to me that local contamination, probably in the home where we have most old products, may be the cause, and this then means we can probably make some local improvements.

This report is making me think seriously of getting rid of foam rubber products, a definite source of breakdown (ever seen how old foam crumbles to powder?) but the problem is finding replacements that aren’t even worse. Looking before leaping.

http://www.accuchem.com/tox/testpanels/datasheets/pbde.htm

Polybrominated Diphenyl Ethers Data Sheet
Source of Exposure

Polybrominated diphenyl ethers (PBDE’s) compose a group of 209 possible isomers. Like Polychlorinatedbiphenyls the comercial products are mixtures of the isomers and are called arachlors. Each individual isomer is a congener.

Polybrominated Diphenyl Ethers (PBDE’s) are a class of chemicals that have replaced polychlorinated biphenyls and polybrominated biphenyls as fire retardants. PBDE’s are used in electronics, electrical cables, carpets, furniture, and textiles. Because of their widespread use typical Americans come in contact with them daily. Worldwide, DecaPBDE’s are the most widely used, followed by Penta and Octa. 95% of the PentaPBDE’s produced annually are used in the USA and research shows that the Penta’s are the most likely to be absorbed by and build up in living organisms.

The environmental rate of increase in the concentration of PBDE’s is increasing exponentially, doubling every 2 to 5 years. Researchers in Sweden found a 60 fold increase in the concentrations of PBDE’s in breast milk between 1972 and 1997. Canadian researchers reported a 15-fold increase in breast milk of women in Vancouver, BC between 1992 and 2002.

The average PBDE concentrations found in breast tissue, blood, and breast milk samples from studies of U.S. women are the highest yet reported in the world. The San Fransico Bay area has the highest environmental concentrations in the U.S.

Symptoms
Potential health effects of PBDE’s have only just begun to be studied, but they have been shown to cause permanent brain damage to fetuses exposed in utero and to be thyroid disrupters. Recent animal research has shown that exposure to low levels of PBDE’s can cause permanent neurological and developmental damage including deficits in learning, memory and hearing, changes in behavior, and delays in sensory-motor development.

A growing body of evidence shows a very low threshold for PBDE to cause permanent impacts to the development of the nervous system. Understanding of the mechanisms involved is lacking but several different mechanisms, including mimicking thyroid hormones, increasing their rate of clearance from the body, and interfering with intracellular communication have been proposed. Early exposure to PBDE has been found to delay the onset of puberty in male and female rats and decrease the weight of the male reproductive organs. Other health effects that have been found in laboratory animals include retarded fetal weight gain, enlarged livers, and raised serum cholesterol. In utero exposures have been associated with serious harm to the fetus, including limb and ureter malformation, enlarged hearts, bent ribs, fused stemebrae, delayed bone hardening, and lower weight gain.

The few studies that have looked at changes in organ structure have found that semi-chronic PBDE exposure can cause thyroid hyperplasia and enlarged livers at 10 mg/kg-day and other adverse effects such as hyaline degeneration, focal necrosis and deformation in the kidney, hyperplastic nodules in the liver, decreased hemoglobin and red blood cell counts at higher doses.

Blood Concentrations
General population data indicates that PCBs are at measurable levels in almost all humans. The population data for the United States indicates an average PCB concentration < 0.03 - 2.0 ppb. (EHS data) However, PCB levels may differ greatly between countries and geographic regions due to variables such as dietary customs and agricultural practices.

Samples
Blood specimens, because of their availability and probable diagnostic value with regard to extent of chronic and acute exposures to PBDE’s, present a convenient tissue for study, providing meaningful data pertinent to the fields of environmental toxicology and clinical ecology. PBDE’s can also be analyzed in breast milk to determine infant exposure and in adipose tissue to look at body burden. 2,2’,4,4’ Tetra and 2,2’,4,4’,5 Penta are analyzed as markers for exposure. 2,2’,4,4’ Tetra is the most abundant congener in the environment and 2,2’,4,4’,5 Penta is the most toxic congener identified up to this point in time

Toxic Concentrations
Concentration that are known to be toxic have yet to be determined. However, malformations of the fetus were consistently seen at levels much lower than doses harmful to the mothers – the lowest being 2 and 5 mg/kg-day respectively.

References
Lunder, Sonya; Sharp, Renee. “Tainted Catch” publication of The Environmental Working Group, 2003.

Darnerud, P.O.; Eriksen, G.S.; Johannesson, T.; Larsen, P.B.; Viluksela, M. 2001. Polybrominated diphenyl ethers: occurrence, dietary exposure, and toxicology. Environ. Health Perspect. 109(Suppl1): 49-68.

Strandman,T.; Koistinen, J.; Vartiainen, T. 2000. Polybrominated diphenyl ethers (PBDEs) in placenta and human milk. Organohalogen Compounds. 47.61-64.

Ohta, S.; Ishizuka, D.; Nishimura, H. et al. 2002. Comparison of polybrominated diphenyl ethers in fish, vegetables, and meats and levels in human milk of nursing women in Japan. Chemosphere, 46(5): 689-96.

Noren, K. and Meironyte, D. 2000. Certain organochorine and organobromine contaminates in Swedish human milk in perspective of past 20-30 years. Chemosphere. 40: 1111-1123.

Meironiti, C.; Bergman, A. 1999. Analysis of Polybrominated Dipenyl Ethers in Swedish Human Milk, 1972-1997. Journal of Toxicology and Environmental Health. Part A, 58:329-341.

Ryan, J.J.; Patry, B.; Mills, P.; Beaudoin, N.G. 2002. Recent trends in levels of Brominated Diphenyl Ethers (BDEs) in Human Milks from Canada. Organohalogen Compounds. 58:173-6.

Kruger C. 1998. Polybrominated biphenyls and polybrominated diphenyl ethers: Detection and quantitation in selected foods. University of Munster, Munster, Germany. Thesis. In National Institute for Environmental Health Sciences (NIEHS) 2001. Toxicological Summary for Selected Polybrominated Diphynyl Ethers. Submitted by Bonne Carson, Integrated Laboratory Systems, Research Triangle Park, North Carolina. March, 2001.

Laws et al. 2003. Study on the dffects of DE71 on female rat pubertal development – presented at the Society of Toxicologist meeting. As cited by L.S. Birnbaum in “New findings on PBDEs”. Talk presented at the Bominated Flame Retardants and Foam Furniture Conference and Roundtable. San Francisco, CA. April 29-30, 2003.

Stoker, etal. 2003. . Study on the dffects of DE71 on male rat pubertal development – presented at the Society of Toxicologist meeting. As cited by L.S. Birnbaum in “New findings on PBDEs”. Talk presented at the Bominated Flame Retardants and Foam Furniture Conference and Roundtable. San Francisco, CA. April 29-30, 2003.

International Program of Chemical Safety (IPCS). 1994. Brominated Diphenyl Ethers. Environmental Health Criteria 162. World Health Organization, Geneva.

Norris, J.M.; Kociba, R.J.; Scwetz, B.A.; Rose, J.Q.; Humiston, C.G.; Jewett, G.L.; Gehring, P.J.; Mailhes, J.B. 1975. Toxicology of octabromobiphenyl and decabromodipheny oxide. Environmental Health Perspectives. 11:153-161.

National Toxicology Program (NTP). 1986. Toxicology and carcinogenesis studies of decabbromodipheny oxide (CAS No 1163-19-5) in R344/N rats and B6C3F1 mice (feed studies). NTP technical report series no 309. Research Triangle Park, NC.

Herrick, T. As Flame Retardant Builds Up In Humans, Debate Over a Ban. The Wall Street Journal, October 8, 2003, Vol. CCXLII NO. 70.

http://www.phschool.com/science/science_news/articles/burned_by_flame_retrdnt.html

Burned by Flame Retardants?
Our bodies are accumulating chemicals from sofas, computers, and television sets
Charlotte Schubert

Two years ago, unnerving news from researchers in Stockholm hit the European press. An analysis of samples of women’s breast milk since 1972 showed dramatic increases in a class of relatively unknown chemicals that toxicologists liken to the notorious pollutants polychlorinated biphenyls (PCBs).

The lesser-known chemicals, polybromo diphenyl ethers (PBDEs), had been noted a year earlier in the Swedish food supply. Soon, researchers in North America also documented an accumulation of PBDEs in women’s milk. They observed PBDEs in fat, too, where the chemicals lodge. Furthermore, PBDEs have been reported in human tissue in Japan, Israel, and Spain.

Studies in Lake Ontario and the Baltic Sea find that PBDE concentrations in fish are rising rapidly, as they are in the fat of marine mammals in California and the Northwest Territories of Canada. The chemicals move up the marine food chain. Concentrations in Baltic Sea species increase successively in herring, salmon, and seals.

Trace amounts of PBDEs leach into the air and sewage, probably from plastics in appliances and computers, foam in upholstery, and fabric of carpets and draperies. Between 5 and 35 percent of such items by weight consist of PBDE flame retardants.

“This stuff is everywhere,” says John Jake Ryan of Health Canada in Ottawa.

Much of the animal data on the toxicity of PBDEs is incomplete, and next to nothing is known about their effects on people. But the results of the animal studies so far lead toxicologists to an unsettling assessment. Says Ilonka A.T.M. Meerts of Wageningen University and Research Center in the Netherlands, “The complete toxic profile is very much like PCBs,” the now-banned chemicals that cause birth defects, thyroid imbalances, and neurological damage in animals and people (SN: 4/9/96, p. 165: http://www.sciencenews.org/sn_arch/9_14_96/fob1.htm; 6/16/01, p. 374: http://www.sciencenews.org/20010616/fob6.asp).

Since the 1970s, PBDEs have been in widespread use as fire retardants in plastics, foam, and textiles. According to the Bromine Science and Environmental Forum, an industry group based in Brussels, Belgium, 148 million pounds of these chemicals are produced each year. Workers in electronics-recycling facilities face unusually high exposures to PBDEs.

The estimated daily intake of PBDEs by people from air and food is far below amounts now known to be toxic to animals. Furthermore, concentrations of PBDEs in human tissue and breast milk are still only one-tenth to one-hundredth the concentrations of PCBs present.

Despite PBDEs’ relative scarceness today, evidence that the chemicals are accumulating in people and the environment raise concerns, given PBDEs’ potential for health effects, says Thomas A. McDonald, a toxicologist at the California Environmental Protection Agency in Oakland. “If concentrations in some marine mammal and human populations continue to rise, PBDEs may be the PCBs of the future,” he says.

In response to such assessments, governments in Europe have moved toward control of the chemicals. On Sept. 6, the European parliament voted to ban the use, manufacture, and import of some forms of PBDE over the next few years (SN: 9/29/01, p. 207). The legislation still requires passage by the European Council of Ministers before it becomes law. The United States and Canada don’t currently regulate the manufacture, distribution, or disposal of PBDEs.

Toxic effects

Concerns about toxic effects of PBDEs arise from many lines of research. In 1998, Per Ola Darnerud of Sweden’s National Food Administration in Uppsala and his colleagues reported to the Nordic Council of Ministers that PBDEs were in the Swedish food supply, tainting fish, milk, and eggs.

The next year, Åke Bergman of Stockholm University, Daiva Meironyte Guvenius of the Karolinska Institute in Stockholm, and their colleagues reported a 60-fold increase in concentrations of these chemicals detected in women’s milk sampled between 1972 and 1997.

Researchers in North America documented what appeared to be a similar, dramatic increase in PBDE concentrations in women’s milk. Ryan and Benoit Patry of Health Canada tested breast-milk samples obtained from several Canadian cities. At the Dioxin 2000 meeting in Monterey, Calif., they reported that milk samples from 1992 contained concentrations of PBDEs 100 times as high as in samples obtained a decade earlier. Preliminary data indicate there were PBDEs in milk from New York women in 1997.

Health officials, however, note that the benefits of breastfeeding an infant outweigh the risks associated with the presence of PBDEs and PCBs in the milk.

Other scientists have examined fat from women in San Francisco. Samples contained a wide range of PBDE concentrations—from 0.017 to 0.462 microgram/gram of body fat. These samples averaged three times as much PBDE as in samples from women in Sweden, Jianwen She of California’s Environmental Protection Agency in Berkeley and his colleagues report in an upcoming issue of Chemosphere. The United States has strict flame-retardant standards for furniture and other household items and uses much of the world’s PBDEs.

In animal studies, PBDE exposure results in pronounced effects on the nervous system. Per Eriksson at Uppsala University in Sweden tested a pair of penta-PBDE compounds. He administered single doses of the compounds to mice 10 days after birth, a critical time in nervous system development. When the mice had grown to adults, Eriksson tested their movement, learning ability, and memory.

Mice that were exposed to any dose of a penta-PBDE compound, from the lowest in the study (0.7 µg/g of body weight) to the highest (12 µg/g), showed abnormal behavior. Those receiving the highest dose of one of the compounds also performed poorly in navigating a maze. Eriksson and his colleagues report their results in the September Environmental Health Perspectives.

At all doses, the nervous system defects worsened as the mice aged. Eriksson’s group has done similar studies with PCB compounds. Describing effects on the nervous system of developing animals, he says, “The PBDEs are as toxic as the PCBs we have investigated.”

Exactly how either PBDEs or PCBs affect the nervous system is unclear. But toxicologists suspect that imbalances in thyroid hormone might play a role. In people and animals, proper regulation of this hormone is critical to the developing nervous system.

Many studies have found that rodents fed high amounts of PBDEs have thyroid hormone deficiencies. In one recent study, a group led by Kevin M. Crofton at the University of North Carolina in Chapel Hill examined thyroid hormone concentrations in blood from rats fed penta-PBDE for 4 days. In rats fed 9 to 13 µg/g of body weight per day, the researchers observed a 20 percent reduction in T4, the primary thyroid hormone in circulating blood. Doses of about 100 µg/g reduced T4 by 70 percent, the scientists reported in the May Toxicological Sciences.

In Crofton’s preliminary assessment: “It appears as if the PBDEs are slightly less potent than the PCBs.”

To put the thyroid studies into perspective, Darnerud estimates that the concentrations of PBDEs that produce an effect on thyroid hormones in animals are 1 million times greater than current exposures in people. It’s hard to compare short-term dosage studies with chronic low-level exposure, he notes, but the gap between animal exposures in the lab and human exposure is immense.

McDonald agrees with Darnerud’s assessment but says, “There is reason to think that the gap might narrow.” He also suggests that people with slight thyroid imbalances might be affected by even small doses of PBDEs. He notes, too, that some animal studies show that toxic effects of PBDEs and PCBs add to each other.

Similar to hormones

Some of the toxic effects of PCBs and PBDEs may derive from their structural similarity to thyroid hormones. PCBs, PBDEs, and thyroid hormones all consist of two six-carbon rings decorated with halogens. Bromine attaches to the carbon rings of PBDEs, chlorine to those of PCBs, and iodine to those of thyroid hormone. In PBDEs, an atom of oxygen bridges the rings, whereas the rings of PCBs and thyroid hormones are linked by carbon-carbon bonds.

The similarity between PBDEs and PCBs, however, doesn’t mean they exert exactly the same effects in the body, cautions Darnerud. “I think it’s perhaps too simple to say that these compounds are alike,” he says.

It’s the bromine atoms in the PBDEs that make them good fire retardants. They quench flames by scavenging electrons. The number and the placement of the bromine atoms determine the type of PBDE. The maximum number of bromines, 10, occurs in deca-PBDE. This substance, which manufacturers use primarily in hard plastics, accounts for more than 80 percent of PBDEs in use today.

Deca-PBDE accumulates in human and animal tissue at far lower concentrations than its cousins with fewer bromines do. In several analyses, deca-PBDE also seems to have much less toxicity. However, Eriksson and his colleagues have found that mice exposed to deca-PBDE as weanlings show behavioral changes equivalent to those exposed to penta-PBDE. The researchers presented their data at the Society for Toxicology meeting in March in San Francisco.

Penta-PBDE, which has five bromines, is the most common form in foam products. But commercial formulations of penta-PBDE contain about 45 percent tetra-PBDE, with four bromines. Penta- and tetra-PBDE appear to break down into potentially more toxic compounds in the body.

Meerts and her colleagues have examined the interaction of PBDE breakdown products, or metabolites, with a blood protein that ushers T4 around the body. The protein, called transthyretin, is one of several T4 escorts in the bloodstream.

In the July 2000 Toxicological Sciences, Meerts reports that PBDE metabolites bind to transthyretin, as PCB metabolites do. Compounds predicted to be metabolic breakdown products of tetra-PBDE bind even more tightly than T4 itself.

Scientists who study PCBs have speculated that transthyretin has a special role in carrying PCBs to the fetus and especially its brain.

Despite PBDEs’ structural similarity to thyroid hormones, McDonald says that “thyroid hormone disruption is not the whole story.”

He notes that laboratory studies of PCBs show that they can upset the intricate balance of nerve cells’ chemical communication system. Preliminary data from Prasada Rao S. Kodavanti of the Environmental Protection Agency in Research Triangle Park, N.C., and his colleagues suggest that PBDEs may disrupt some of the same communication processes, reports McDonald in an upcoming issue of Chemosphere.

Millions of sources

How PBDEs from sofas, carpets, computer monitors, and television sets get into people is an open question. “You have millions of point sources in every home, every bus, every car, and they are slowly making their way into the environment and up the food chain,” says McDonald.

After analyzing food in Ottawa grocery stores, Ryan estimates that the average person there eats 0.044 µg of PBDE per day in meat and dairy. But scientists don’t yet know how food gets contaminated in the first place.

In the United States, spreading sewage waste on farmland as fertilizer may send PBDEs along to the dinner table. Robert C. Hale of the Department of Environmental Science in Gloucester Point, Va., and his colleagues measured PBDEs in U.S. sewage sludge. They report in the July 12 Nature that each kilogram of sludge, by dry weight, carries 1.1 to 2.3 milligrams of PBDEs with five or fewer bromines. That exceeds 100,000 times the concentration that other researchers found in some European sludge samples. About 4 million tons of sewage sludge were applied last year to land in the United States, according to EPA.

Discarded furniture may contribute to the pollution in sludge, suggests Hale. As they degrade, couch and chair cushions release large amounts of penta-PBDE into dirt, sewers, and sediments, he suspects.

Flame-suppression standards save lives, says Robert Campbell of the American Chemistry Council in Arlington, Va.

“We may have to look at issues of risk tradeoff, but … there are flame retardants other than PBDEs,” says Linda Birnbaum, director of the human studies division at EPA’s National Health and Environmental Effects Research Lab in Research Triangle Park, N.C. She notes, “We banned the production of PCBs when we had less information than we do now of the PBDEs.”

Fire-squelching substitutes for PBDEs include other bromine-containing compounds and silicon or phosphorus-based chemicals. Some of these may gradually degrade in products, weakening their fire-retardant properties, notes Campbell.

Birnbaum adds that some substitutes may themselves be toxic.

Less ambiguous are the data that show PBDEs accumulating at a rapid rate in the fat of people and animals in North America. “Current concentrations [of PBDEs] are still quite low,” says Crofton. Like many other toxicologists, he is particularly concerned about the future.

Adds Darnerud, “I don’t want to see levels get as high as PCB levels.”

Letters:

Couched in language peppered with mays, the article suggests that we are all being poisoned with PBDEs from sewage sludge applied to farmland. However, sludge with high concentrations of volatile organics isn’t qualified in most jurisdictions of which I am aware for land application. It’s usually sent to a landfill or incinerated.

Couches and chair cushions don’t appear in sewage plants, and therefore PBDEs in those objects don’t appear in the plants’ sludge, at least not directly. Such objects go to landfills, and sludge from treatment of leachate from such landfills is never applied to land. Finally, in the United States, sludge is not supposed to be put on land growing crops for human consumption or for consumption by animals consumed by humans. I therefore suspect it to be highly improbable that there’s a direct connection between sludge and the dinner table in the United States.

McClellan G. Blair
Indiana, Pa.

The article appears to have a discrepancy. The text’s description of the structural similarities between the three types of molecules doesn’t agree with the figure of the structures of the molecules of PBDE-100, PCB-153, and thyroxine.

The text states that the carbon rings of PBDE are joined by an oxygen atom, while those of PCB and thyroxine are joined by a carbon-carbon bond. In the figure, the rings in thyroxine appear to be joined by an oxygen atom in the same manner as the PBDE-100. Something seems awry.

Edward Brosius
Saline, Mich.

Correct. It’s incorrect. The text should have read: “In PBDEs and thyroid hormones, an atom of oxygen bridges the rings, whereas PCBs are linked by carbon-carbon bonds.” Therefore, says Thomas A. McDonald of California’s Office of Environmental Health Hazard Assessment, PBDEs structurally resemble thyroid hormones even more closely than they resemble PCBs.—The Editors

This article presents incomplete information on polybrominated diphenyl ethers (PBDEs). The troubling aspect of this article is its call for reducing or banning the use of these life-saving products. The importance of brominated flame retardants should be pointed out in any article addressing their use because thousands of people are injured or die in fires around the globe each year. In the United States alone, fires kill about 4,000 people annually, with another 20,000 people suffering serious injury from burns and property losses totaling about $4.5 billion.

Courtney M. Price
American Chemistry Council
Arlington, Va.

********

References and Sources for this Article

References:

Hale, R.C., … and W.H. Duff. 2001. Persistent pollutants in land-applied sludges. Nature 412(July 12):140-141.

Meerts, I.A., et al. 2000. Potent competitive interactions of some brominated flame retardants and related compounds with human transthyretin in vitro. Toxicological Sciences 56(July):95.

Zhou, T., et al. 2001. Effects of short-term in vivo exposure to polybrominated dipher ethers on thyroid hormones and hepatic enzyme activities in weanling rats. Toxicological Sciences 61(May):76.

Further Readings:

Raloff, J. 2001. Memory problems linked to PCBs in fish. Science News 159(June 16):374.

______. 1996. Banned pollutant’s legacy: Lower IQs. Science News 150(Sept. 14):165. Available at http://www.sciencenews.org/sn_arch/9_14_96/fob1.htm.

Sources:

Åke Bergman
Department of Environmental Chemistry
Wallenberg Laboratory
Stockholm University
106 91 Stockholm
Sweden

Bob Campbell
Great Lakes Chemical
1801 Highway 52 North
West Lafayette, IN 47906

Kevin M. Crofton
Neurotoxicity Division
National Health and Environmental Effects Research Laboratory
U.S. EPA
Research Triangle Park, NC 27711

Per Ola Darnerud
National Food Administration
Toxicology Division
P.O. Box 662
751 05 Uppsala
Sweden

William H. Duff
Department of Environmental Science
Virginia Institute of Marine Science
P.O. Box 1346
Gloucester Pt., VA 23063

Per Eriksson
University of Uppsala
Box 256
751 05 Uppsala
Sweden

Daive M. Gevenius
Department of Medical Biochemistry and Biophysics
Karolinsa Institute
171 77 Stockholm
Sweden

Robert C. Hale
Department of Environmental Science
Virginia Institute of Marine Science
P.O. Box 1346
Gloucester Pt., VA 23062

Prasada Rao S. Kodavanti
Cellular and Molecular Toxocology Branch
National Health and Environmental Effects Research Laboratory
U.S. EPA
Research Triangle Park, NC 27711

Thomas A. McDonald
Office of Environmental Health Hazard Assessment
California EPA
1515 Clay Street, 16th Floor
Oakland, CA 94612

Koidu Noren
Department of Medical Biochemistry and Biophysics
Karolinska Institute
171 77 Stockholm
Sweden

Jianwen She
Hazardous Materials Laboratory
California Department of Toxic Substances Control
California EPA
2151 Berkeley Way
Berkeley, CA 94704

From Science News, Vol. 160, No. 15, Oct. 13, 2001, p. 238.

http://theses.lub.lu.se/postgrad/search.tkl?field_query1=pubid&query1=sci_606&recordformat=display

Date published: 2003
Publisher: Arnout ter Schure, Dept. of Ecology, Chemical Ecology and Ecotoxicology, Sölvegatan 37, 22362, Lund, Sweden
Theses defended: Friday 3 October, Blå Hallen, Ecology Building, Sölvegatan 37, Lund
The faculty’s opponent: Prof. Steven Eisenreich, Institute for Environment and Sustainability, Joint Research Centre of the European Commission, Dept. Inland and Marine Waters, Ispra (VA), Italy
Classification: Ecology
Keywords: Atmosphere; Baltic Sea; Deposition; Frogs; Global Fractionation; Latitude; PBDE; PCB; Sources; Spatial Variation; Substance Flow Analysis; Temperature; Washout ratio

Abstract: I have studied the sources, long range transport, and rates of flow of polybrominated diphenyl ethers (PBDEs), from the technosphere to the Baltic ecosystems. PBDEs are mainly used in polymers, which are applied in electrical equipment to prevent overheating or flashover and are produced in large quantities. PBDEs have become widely spread in the environment, where they are able to accumulate in biota (i.e. concentrations of PBDEs in human milk increase similar to that observed in wildlife) and induce toxic effects, such as thyroid disruption and neurological damage.

To identify sources of PBDEs, air and precipitation were sampled at a municipal solid waste treatment plant (MSW) with an electronics recycling facility. Concentrations in both precipitation and air were higher at the MSW than at a reference station. Concentrations in air and rain at the reference station were depending on wind direction and higher levels were found when winds were blowing from the MSW area. It was concluded that treatment of waste and electronics recycling is presently a source of “old” PBDEs (Tetra-BDE47 and Penta-BDE99) to the environment, whereas Deca-BDE209 concentrations are more a result of proximity to potential diffuse sources. A negative relationship between the particulate PBDE concentration and rain volume was found, suggesting a dilution effect and indicating the importance of particle scavenging for wet deposition.

To examine the distribution of PBDEs over Sweden, common frogs (Rana temporaria) were used as bioindicators. BDE47 was found in almost all frogs analysed, whereas BDE99 was detected in less than half of the frogs. PBDE concentrations were compared with that of PCBs. The fate of PCBs is well documented and believed to be similar to that of the PBDEs. I showed that PBDE and PCB concentrations in frogs were latitude related, supporting the global distillation theory. PBDE concentrations were significantly correlated with PCB concentrations, indicating similar contaminant sources and an analogous environmental fate. The PCB concentrations were one to two orders of magnitude higher than that of the PBDEs at southern latitudes, but the difference decreased to the north.

To assess the long range transport and input of PBDEs to the Baltic Sea, air and atmospheric deposition were sampled on Gotska Sandön, situated in the central basin of the Baltic Sea. As predicted by their physicochemical properties, low brominated congeners were in the gas/dissolved phase, whereas higher brominated PBDEs were more in the particle phase, affecting their respective modes of transport. BDE209 was compared to PCBs and other PBDEs and shown to be the most dominant pollutant in the atmosphere of the Baltic Sea region. This could be attributed to DecaBDE’s currently high consumption volume. I found that PBDE and PCB concentrations were highly correlated, indicating that their overall atmospheric transport is likely driven by the same mechanism. However, a difference was observed between the commercial DecaBDE formulation, BDE209 and the Penta-BDEs BDE47, 100, and 99. This suggested different underlying processes between “old” commercial PentaBDE and “new” DecaBDE formulations when transported over long distances through the atmosphere.

Abstract: För att kunna förstå och bedöma exponeringen av kemikalier i miljön, i det här fallet PolyBromeradeDiphenylEtrar (PBDEer), behövs kunskap om källor och flöden från teknosfären till ekosystemen. PBDEer är bromerade flamskyddsmedel som bl a sätts till olika plastmaterial i elektronikanvändning för att förhindra brand. Det används globalt i miljontals kilo och presenteras av kemikalienbranschen som den mest effektiva metoden för brandskydd. Men PBDEer sprids, bioakummuleras (halterna i både i bröstmjölk samt djur ökar exponentiellt) och är giftiga. Ämnena stör hormonbalansen hos mammalier och påverkar nervsystemets utveckling och funktioner.

Jag utvecklade först metoder för att kunna mäta PBDEer i olika miljömatriser (luft, vatten och djur) och för sedan kunna analysera substanserna. Både luft och regn valdes som lämpliga matriser eftersom det förväntades att PBDEer sprids genom transport i atmosfären i likhet med andra persistenta miljögifter som t.ex. PCB. Nederbörd samlades in under hösten 2000. Eftersom inga tidigare studier genomförts avseende PBDEer i nederbörd valdes långa provtagningsperioder (2 veckor) som genomfördes med målsättningen att fasseparera PBDEer i löst och partikelbunden form. PBDEer fanns i mätbara halter, var till största delen partikelbundna och nedfallet från atmosfären var jämförbart med nedfallet för PCBer i södra Sverige. Deca-BDE209, den PBDE som används mest i samhället idag, visade också högst halter. Jag fann ett negativt samband mellan regnmängd och koncentration av partikulärt bundna PBDEer. Sambandet visar att PBDEer tvättas ur luften mycket effektivt när de är bundna till partiklar och att detta sker i början av ett regntillfälle.

Genom att mäta PBDEer i luft och regn vid avfallsbehandlingsföretaget SYSAV (i Malmö, företaget tar årligen emot 476000 ton avfall varav drygt 2000 ton är elektroniska produkter för återvinning) utrustat med en återvinningsstation för elektronik, vid en lokal nära SYSAV (NCC) och vid en opåverkad lokal identifierades PBDEers lokala spridningsmönster. Resultaten visade att PBDE halterna i luft och nederbörd var signifikant högre vid SYSAV jämfört med NCC och referenslokalen. I enlighet med PBDEers fysiska och kemiska egenskaper beror substansernas associering till partiklar i atmosfären på bromeringsgraden. Detta innebär att lågbromerade PBDEer huvudsakligen finns i gasfas medan högbromerade PBDEer mest är bundna till partiklar. Detta påverkar ämnenas spridning. Koncentrationer i luft och regn vid referenslokalen var beroende på vindriktningen och högre halter uppmättes då vindriktningen var från SYSAV området. Jag drar därför slutsatsen att elektronikåtervinning och behandling av avfall som innehåller PBDEer leder till utsläpp i miljön.

För att få en bild av den storskalig spridningen av flamskyddsmedel till Östersjön initierades en provtagning på Gotska Sandön i samarbete med personal från SMHI:s väderstation på ön. Ön ligger i centrala Östersjön, och har tidigare visats vara en representativ mätpunkt för PCB i området. Omkring 100 luft- och regnprov insamlades, uppdelat i partikulär och löst fas. Mina resultat visar att även här kan PBDEer spåras, i såväl luft som regn. I likhet med tidigare resultat så dominerade Deca-BDE209, som representerar den “nya” och mest använda kommersiella PBDE användningen i samhället och som ersatt andra produkter där Tetra-BDE47 och Penta-BDE99 dominerade. Dessa flamskyddsmedel respresenterar de “gamla” kommersiella blandningarna, vilket har börjat fasas ut enligt direktiv från EU.

Slutligen studerades den storskaliga spridningen och förekomsten av flamskyddsmedel över hela Sverige. Detta genomfördes genom att analysera PBDEer i vanlig groda (Rana temporaria). Ca 200 grodor samlades in på 7 lokaler, från Lund i söder till Kiruna i norr. Den mest förekommande PBDEn, Tetra-BDE47, återfanns i nästan alla djur, i likhet med olika PCBer. Vi visade att halterna av PBDE och PCB i grodorna är relaterade till latituden, men skiljer sig för olika individuella föreningar. Resultaten stöder teorien om global destillering. Jämfört med PCB, som inte används längre i Sverige, sprids PBDE från ett flertal källor fördelat över landet. PCB, å andra sidan, påverkas av temperaturen (som är relaterad till latituden) och minskar från söder till norr. Halterna av PBDE och PCB var signifikant korrelerade i grodorna, vilket tyder på att ämnena sprids och ackumuleras i djur enligt samma mekanismer.

Resultaten tyder på att PBDEer har spridit till miljön i mycket stor utsträckning och i samma omfattning som PCBer. Källorna för båda ämnesgrupperna är vanligtvis diffusa. Resultaten kan ligga som grund för en riskbedömning av flamskyddsmedel, där flödet av ämnena från teknosfären till olika ekosystem är en viktig byggsten och ackumulering i djur är en annan.

List of papers in this dissertation

I) ter Schure, A.F.H., Larsson, P., 2002. Polybrominated diphenyl ethers in precipitation in Southern Sweden (Skåne, Lund). Atmospheric Environment 36, 4015-4022.
II) Agrell, C., ter Schure, A.F.H., Larsson, P., Sveder, J., Bokenstrand, A., Zegers, B. Polybrominated diphenyl ethers (PBDEs) at a solid waste incineration plant I: Atmospheric concentrations. (Submitted).
III) ter Schure, A.F.H., Agrell, C., Larsson, P., Bokenstrand, A., Sveder, J., Zegers, B. Polybrominated diphenyl ethers (PBDEs) at a solid waste incineration plant II: Atmospheric deposition. (Submitted).
IV) ter Schure, A.F.H., Larsson, P., Merilä, J., Jönsson, K.I., 2002. Latitudinal fractionation of polybrominated diphenyl ethers and polychlorinated biphenyls in frogs (Rana temporaria). Environmental Science and Technology 36, 5057-5061.
V) ter Schure, A.F.H., Larsson, P., Agrell, C., Boon, J.P. Atmospheric transport of PBDEs and PCBs to the Baltic Sea. (Submitted).