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The next PCBs?

September 23, 2003

Mother's Milk: The next PCBs?

As less combustible products like cotton and wood have been replaced by highly flammable synthetic materials in consumer products, chemical fire retardants have become ubiquitous. There are many different kinds of fire retardants with varying degrees of toxicity. A group of brominated fire retardants (BFRs) called polybrominated diphenyl ethers, or PBDEs, have come to the attention of scientists and regulators because of evidence of their environmental persistence and bioaccumulation in living organisms, as well as their toxic effects. Today PBDEs are in thousands of products, in which they typically comprise five to 30 percent of product weight. [1] During manufacturing, PBDEs are simply mixed into the plastic or foam product, rather than being chemically bound to the material as some other fire retardants are, making them more likely to leach out into the human environment.




Brominated Fire Retardants are found in everyday consumer products


Materials used in

Types of PBDEs used

Examples of consumer products

Plastics

Deca, Octa, Penta

Computers, televisions, hair dryers, curling irons, copy machines, fax machines, printers, coffee makers, plastic automotive parts, lighting panels, PVC wire and cables, electrical connectors, fuses, housings, boxes and switches, lamp sockets, waste-water pipes, underground junction boxes, circuit boards, smoke detectors

Textiles

Deca, Penta

Back coatings and impregnation of home and office furniture, industrial drapes, carpets, automotive seating, aircraft and train seating

Polyurethane foam

Penta

Home and office furniture (couches and chairs, carpet padding, mattresses and mattress pads) automobile, bus, plane and train seating, sound insulation panels, imitation wood, packaging materials

Rubber

Deca, Penta

Conveyor belts, foamed pipes for insulation, rubber cables

Paints and lacquers

Deca, Penta

Marine and industry protective lacquers and paints


Source: [1], [112]




PBDEs are the chemical cousins of PCBs, another family of highly persistent and bioaccumulative toxicants that came to the attention of health officials only after millions of pounds had been released into the environment. In the 26 years since PCBs were banned, numerous studies have documented permanent, neurological impairment to children from low level PCB exposure. [2, 3, 4, 5, 6] Recent evidence suggests PBDEs and PCBs may work together to cause adverse health effects. Not only do PBDEs appear to be acting through the same pathways as PCBs, but also exposure to a combination of PCBs and PBDEs appears to affect motor skills of lab animals ten times more strongly than exposure to either chemical alone. [7, 8]

Types of PBDEs

There are 209 types, or congeners, of PBDEs, classified by the number of bromine atoms in a molecule of the chemical: Penta-BDEs have five bromine atoms, octa-BDEs have eight, deca-BDE has 10, and so on. Commercial fire retardants containing PBDEs are actually mixtures of several different congeners, with the three major commercial mixtures called Deca, Penta, and Octa. The common name of the commercial product can be somewhat misleading; the Penta product, for example, is actually a mixture of 40 percent tetra-BDE, 45 percent penta-BDE and 6 percent hexa-BDE congeners. The product known as Deca is mostly made up of PBDEs with 10 bromines, but PBDEs with eight or nine bromines make up about 2% of the mixture. Overall, a small number of PBDE congeners are predominant in commercial fire retardant mixtures and in the environment.


Graphic: Composition of Commercial Mixtures

The use of these fire retardants has skyrocketed in the last three decades, with Penta production almost doubling between 1992 and 2001. [9, 10] Worldwide, Deca is the most widely used of the PBDEs with 83 percent of the global market by weight, followed by Penta with 11 percent and Octa with 6 percent. [10] The market for PBDEs took off after the 1978 ban of a related class of brominated fire retardants called polybrominated biphenyls, or PBBs. Once widely used as fire retardants, PBBs were banned following the detection of contaminated cattle feed in Michigan during 1973 and 1974 that exposed 9 million people to tainted meat and dairy products. [11]

Today, half of the PBDEs used worldwide are used in the Americas — 73 million pounds in 2001 alone. [10] Led by the U.S. and Canada, the Americas consume 95 percent of the global supply of Penta, which is the type most easily taken up by animals and people. An unknown amount of PBDEs, probably millions of pounds, is also imported into the country each year in manufactured goods. Chemical industry analysts say the North American market for brominated fire retardants is $1 billion a year and growing by about 3.7% annually; the European market is a little more than half that size. [12] PCB use in the US peaked at 86 million pounds per year in 1970. PBDE use in the US and Canada is approaching this level with 73 million pounds consumed in 2001. In total, almost as many pounds of PBDEs have been released into the environment in the US as PCBs.

Only eight companies manufacture PBDEs worldwide, with the two largest in the U.S.: Great Lakes Chemical Corp. of West Lafayette, IN, and Albemarle Corp. of Richmond, VA. In 2002, Great Lakes reported total sales for all products of $1.4 billion, up 4% from the previous year. Albermarle reported sales of $980 million, up 7%. [13, 14] The corporations are already notorious as the manufacturers of methyl bromide, a volatile, acutely toxic, ozone-depleting pesticide gas used to fumigate strawberries, tomatoes and other crops. (Albemarle also has the dubious distinction of being a spin-off of Ethyl Corp., whose leaded gasoline additive was banned in the U.S. in 1972.) The main areas of bromine production in the world are southeastern Arkansas, where Great Lakes and Albemarle pump it from underground pools of brine, and Israel, where a company named Dead Sea Bromine extracts it from the briny inland sea. A chemical industry journal describes the global trade in brominated chemicals as "an oligopoly controlled by Albemarle, Great Lakes and the Dead Sea Bromine Group." [15]




Brominated fire retardants widely used in the Americas

Global Use of PBDEs in 2001 (pounds)


Commerical PBDE Product

Americas

Europe

Asia

Other

Percent used in the Americas

Deca

54,010,000

16,760,000

50,710,000

2,315,000

44%

Penta

15,650,000

331,000

331,000

221,000

95%

Octa

3,307,000

1,345,000

3,307,000

397,000

40%


Source: [10]




Despite their heavy use, until recently data were scarce on the toxicity or environmental fate of PBDEs. But in the last few years, it has become clear that PBDEs and other brominated fire retardants have joined PCBs, DDT and dioxin on the list of persistent, bioaccumulative chemicals contaminating people, animals and the environment everywhere on the planet. These fire retardants are now found in house dust, sewage sludge and the water and sediments of rivers, estuaries and oceans. They've been found in the tissues of whales, seals, birds and bird eggs, moose, reindeer, mussels and dozens of species of freshwater and marine fish. [16, 17, 18, 19, 20, 21] Brominated fire retardants have been detected in birds and marine mammals in remote locations including the North Sea, the Baltic Sea and the Arctic Ocean — far from areas in which they are used. [22] Like scores of other industrial chemicals, they have also been found in human breast milk, fat and blood.


Fire retardant levels rising rapidly in the environment

Of greatest concern is the exponential rate of fire retardants' increase in the environment. Over the past 20 years, rising levels of PBDEs have been documented by almost every study that looked at trends over time. Earlier this year EWG compared fish caught in San Francisco Bay in 2002 to those caught in 1997 and found PBDE levels in two key indicator species (striped bass and halibut) to be doubling every 2.8 and 3.9 years, respectively. [23] Levels of PBDEs were 100 times higher in San Francisco Bay harbor seals in 1998 than they were 10 years earlier. [24] Similar findings are reported for fish in the Columbia River in Washington State and in the Great Lakes. [25, 26] Around the world researchers have documented similar dramatic increases in wildlife and humans: ringed seals from the Canadian arctic, beluga whales near Baffin Island, blood in the U.S. and Norway, and breast milk in Canada and Sweden. [18, 27, 28, 29, 30]

Research shows that the PBDEs containing 3, 4, and 5 bromines are the most likely of the PBDEs to be absorbed by and build up in living organisms. Penta PBDE is almost exclusively used in flexible polyurethane foam for home and office furniture, carpet padding, and mattresses. About 7.5% of the more than 2.1 billion pounds of flexible polyurethane foam produced in the U.S. each year contains Penta. [31] Fire retardants must be added to foam furniture sold in California, to meet the world's most stringent standards for fire retardancy. [32] Other manufacturers use fire retardants to avoid liability for fire-related injuries. However, the U.S. Consumer Products Safety Commission has said that the same level of fire safety the California furniture standards were designed to achieve can be attained without adding chemical retardants to foam. [33]

PBDEs are thought to enter the human body through exposures to contaminated food, house dust and air. Food is thought to be the major PBDE exposure route for Europeans. The highest levels of PBDEs in foods are typically found in fish. [34, 35, 20] Lower levels are have been documented in chicken [36], other meat and animal fats. [35, 20, 11, 37] Food consumption might not be the dominant source of PBDEs among people in the U.S. and Canada, where the levels of PBDEs found in the human body, household dust, sewage sludge, wildlife and the environment are at least 10 times higher than in other industrialized nations. [38, 39, 40, 41, 42, 43] These findings suggest that inhalation and ingestion of PBDEs in the ambient environment may be significant routes of exposure in North America. [44]

  composition of commercial PBDE mixtures