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||Last Updated: Nov 12th, 2006 - 20:38:00
By Diana Simms
Older computers may emit significant amounts of toxic polybrominated diphenyl ether (PBDE) flame retardants, particularly those light PBDEs, according to new research published on November 1, 2006 on the Environmental Science and Technology's Research ASAP website.
Stuart Harrad and Sadegh Hazrati of the University of Birmingham conducted the study and found that older computers are a major source of light PBDEs, which are more harmful than heavy ones such as Deca PBDEs, according to the authors.
The discovery was unexpected as it was found when they were monitoring PBDE levels in an office where a computer purchased in 1998 was replaced with a newer model, the authors said.
They found that on installing the newer model, PBDE levels in the office showed a dramatic drop from 431 picograms per cubic meter (pg/m3) to less than 95 pg/m3.
Such levels of PBDEs are not terribly high when they are compared to those found in North America where ten times higher concentrations have been detected, according to a November 1, 2006 news story by the American Chemical Society.
PBDEs are a group of chemicals used primarily as flame-retardants in many polymer resins and plastics to replace polychlorinated biphenyls (PCBs), which have been banned for more than 30 years for their toxicity. Experts worry that PBDEs may impose similar risks as both PCBs and PBDEs are chemically similar.
PBDEs, suspected endocrine disrupters, persist in the environment, polluting soil, air and water. Recent research has indicated that they cause behavioral disturbances in rodents. Animal studies promoted researchers to believe that among others, PBDEs also interfere with liver and thyroid functions. But direct evidence to suggest they cause harm in humans is scarce.
Heather Stapleton, assistant professor at Duke University's Nicholas School of the Environment, said that the current study highlighted the difference in what the industry projects and what actually happens in laboratory conditions.
"This paper highlights the problem [of] relying upon information from industry sources regarding applications of commercial [PBDE formulations] to specific types of products," she added.
The presence of lighter PBDEs in older computers can be a concern since it could be indirectly responsible for high concentrations of PBDEs found in house dust, according to Miriam Diamond, professor of the University of Toronto.
But computers are not the only household products that carry PBDEs. As flame-retardants, PBDEs are also used in other household products including TV, carpets, furniture and other utilities that need protection from flames and fires.
Cars may be the biggest polluter with regard to PBDEs as Harrad and Sadegh Hazrati found the highest levels of PBDEs inside cars, which can be as high as 8200 pg/m3, representing "the most contaminated microenvironment of all the homes, offices, public microenvironments, and cars studied."
A January 2006 report by the Ecology Center has revealed earlier that PBDEs inside cars can be ten times higher than that found inside houses and commercial offices although the levels varied significantly in cars made by different manufacturers.
In Europe, out of the same concern about PCBs, two PBDEs have already been banned and another one is waiting to be phrased out, foodconsumer.org reported in 2005. But no report indicated that the US government had banned any PBDEs.
PBDEs are ubiquitous, even found in Mother's milk, according to the Environmental Working Group, which reported that "The handful of studies conducted show that PBDE concentrations found in U.S. women and children are the highest reported in the world — and increasing rapidly."
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