Lifesaving Chemical Pollutes Water

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Lifesaving Chemical Pollutes Water

07-Feb-2002

A lifesaving chemical which is used to make upholstery flame- resistant,

pentaBDE (penta bromo diphenyl ether), has turned up in water supplies and

even in breast milk.

Freshwater fish in Virginia have been found to contain the highest reported

levels in the world. It's showing up in animals and humans around the globe.

PentaBDE has also been found in sewage sludge that is spread on farmland

across the United States.

It's been linked to behavioral problems in laboratory animals, but little is

known about its effects on humans. In one Swedish study, 10 day old mice

that were given large doses of the two major chemicals in commercial

pentaBDE showed permanent disturbances in their behavior, memory and

learning.

Some of the compounds in pentaBDE, including its BDE molecules, are similar

in structure to PCBs (polychlorinated biphenyls), industrial chemicals which

are classified as probable carcinogens. PCBs are known to cause birth

defects, neurological damage and thyroid imbalances. Their use was banned in

the U.S. in 1976. The chemical structure of BDEs also resembles thyroxin, a

thyroid hormone. Initial studies indicate that BDEs could interfere with the

metabolism of thyroid hormones.

Virginia researchers examined more than 1,000 fish from 332 different

locations in the Roanoke and Dan River basins. 33 species of fish were

tested, including striped bass, catfish and carp. The scientists found that

89 percent of the fish were contaminated with BDE-47, one of the two main

constituents of pentaBDE. One carp from the Hyco River contained more than

47 parts per billion of BDE-47, the highest known amount to be recorded in

any fish so far.

BDE chemicals do not readily break down in the environment, and they

accumulate in the tissues of animals. They get into humans mainly through

food. Levels of BDEs in the breast milk of North American women over the

last decade has increased from two to 200 parts per billion. One of the

major concerns is the exposure of infants to BDEs in breast milk.

Researchers in Canada have compared amounts of the chemical in archived

trout samples with trout caught in recent years. " We found that trends are

rapidly rising in lake trout from Lake Ontario, " says Mehan Alaee, an

Environment scientist. " BDEs increased 300-400 times from 1978 to 1998, " he

says.

The European Commission approved a ban on pentaBDE, effective in July 2003,

and the European parliament has recently proposed extending that ban to

include other BDEs. In Japan, pentaBDE concentration in fish has dropped

because of voluntary reductions. But demand for the chemical continues to

increase in the United States, which accounts for 98 percent of worldwide

use. Production of pentaBDE doubled to 8,500 tons between 1992 and 1999.

Scientists are still trying to determine how the flame retardants enter the

environment. " We just don't know for sure, " says Hale of the Virginia

Institute of Marine Science. PentaBDE is added to polyurethane cushions,

such as those found in vehicles and household furniture, to delay ignition

and slow down fires. Hale thinks the chemical could seep into the

environment, ending up in storm sewers, when discarded cushions

disintegrate.

Environmental regulators will have to weigh the potential environmental and

human health effects of pentaBDE against its known life saving properties,

when deciding whether to restrict its use. In residential fires, pentaBDE

can slow down a fire, allowing residents time to escape and reducing

property damage. A BDE treated sofa, for example, would be slower to ignite

and could increase escape time by a factor of 15.

Under a pilot program of the U.S. Environmental Protection Agency, the main

U.S. manufacturer of pentaBDE, Great Lakes Chemical, is now voluntarily

testing whether children's exposure to PBDEs presents a risk. Bob ,

of Great Lakes Chemical, says the Swedish toxicological study indicating

pentaBDE produced permanent damage in mice " was not done using the generally

accepted method. "

The discovery of significant amounts of BDEs in sewage sludge used as

fertilizer concerns scientists because of the potential for more of these

chemicals entering the food supply. " Sewage sludge contains everything -

literally - in the kitchen sink, " says Hale.

The original EPA risk assessment of sewage sludge concluded that it was safe

to apply to land. However, the assessment did not consider BDEs. In the

U.S., 60 percent, or about four million tons a year, of the sewage sludge is

now spread on land as a fertilizer. In Europe, several countries are

reevaluating its use as a fertilizer. In September 2001, Swiss authorities

proposed banning the disposal of sewage sludge on agricultural land by 2005.

In 1999, the Swedish Farmers Association issued a temporary ban on spreading

sewage sludge on farmland because of concern over potentially hazardous

chemicals, including BDEs, in the sludge.

Hale says, " Our major point on the whole sludge issue is that the EPA

has done a risk assessment on a number of chemicals but they've left more

chemicals out than they've considered. "