August 23, 2008
Toxins Which Affect Immune System Found in Schools
By Emma Brady
Researchers at a Midland university have found that dust found in some of the region's primary school classrooms is contaminated with high levels of pollutants and chemicals which could prove toxic.
Birmingham University, which presented its results to the Dioxin 2008 conference on Thursday, found the dust contained concentrations of HBCD, TBBP-A, PFOS, and PFOA.
All four chemicals are persistent organic pollutants (POPs) which do not degrade in the environment, instead they accumulate over time in human or animal tissue creating potential risks to human health and the environment.
HBCD is often used in wall insulation, electronics and fabric coating, while TBBP-A is a flame retardant used in electronic equipment like computers. Both chemicals have been shown to have toxic effects on the human hormone system.
PFOS and PFOA are chemicals widely used to stain proof fabrics and carpets.
Scientists at the university took samples from 20 primary school classrooms across the West Midlands using a specially modified vacuum cleaner. Dust samples were then chemically analysed in the laboratory to measure levels of concentration and toxicity.
They found that levels of HBCD in classroom dust were significantly higher than that from samples in offices and homes.
Levels of TBBP-A were similar to those found in dust from homes, but higher than samples taken from cars and offices.
Too little is yet known about concentrations of PFOS and PFOA in indoor dust to evaluate how classroom levels compare with those in other indoor environments.
Emma Goosey, who presented the study to the conference, held at the International Convention Centre, said: "Our results show that classrooms contain significant levels of these compounds.
"We already know that children are more likely than adults to be exposed to persistent organic pollutants by consuming dust. We also know that they are also more susceptible to the effects of such chemicals.
"The levels in classrooms seem to be higher than some other common environments probably because of the high numbers of computers and fire/stain retardants used in furniture. Because they can accumulate in the body it is important that we monitor levels of exposure across our lifespan."
The team used their findings to calculate a child's likely exposure from ingesting dust, which showed exposure to HBCD and TBBP- A is significant, while classroom exposure to PFOS and PFOA is below the advised levels set by the Government.
Dr Stuart Harrad, who is a member of the Government's Dioxin Strategy Group and chair of Dioxin 2008, added: "Dust seems to be a major source of childhood exposure to these compounds.
"Our initial work suggests that exposure in classrooms is within safe levels for some chemicals, but may not be for other widely- used chemicals, and more work is needed to assess how exposure from various sources accumulates - particularly as these chemicals remain within the body.
"Health risks are likely to occur from prolonged exposure from several sources, so one area that we are currently looking into is children's exposure to compounds that could metabolise into POP chemicals within the body."
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