Newsletter #1 March 2008

Trace flame retardant levels in serum sparking discussion on human exposure



cbIt’s another long chemical name, decabromodiphenyl ether (or BDE209) - a flame retardant that is being analyzed on a regular basis at IVM’s laboratory. The interest in this compound arises in part from the European Union’s current efforts to assess the risk this product poses to environmental and human health. The EU needs high quality monitoring data to use in risk assessment models. IVM has been analyzing the concentration of this chemical in eggs of predator birds, sewage sludge and estuarine sediments for the past two years, and has recently begun analysis of human serum samples from four European countries. This work falls within two 10-year monitoring projects that are sponsored by BSEF (Bromine Science Environmental Forum, Brussels, Belgium).
 
While less complicated to detect in sewage sludge, sediments or even house dust, BDE209 poses a major challenge to scientists trying to quantify levels in human serum. That’s because in a gram of human serum, we normally expect to find no more than a small number of picograms of BDE209.
 
The IVM laboratory has developed and validated a highly-sensitive method to detect this flame retardant in human serum. One of the tricks that had to be mastered was to keep practically all the interference from background BDE209 levels at the laboratory out of the samples during extraction, extract purification and chemical analysis steps. Only then are such tiny amounts visible as peaks in chromatograms generated when the sample extract is analyzed with gas chromatography. One way to check that there is no background signal in the analytical system is to analyze a sample in which we are sure BDE209 is absent (a blank) – such as analytical grade water (which cannot dissolve any BDE209) - although the calf serum samples that IVM acquired and purified have also proven to be equally pure – and are being used for checking the background of the analytical method every time human serum is analyzed.
 
The exposure routes that this flame retardant takes to enter our bloodstreams will be examined by epidemiologists from IRAS (Utrecht University) who are working together with IVM. IRAS has collected data from blood donors to learn more about the factors in homes and diets that might affect the levels of flame retardants found in serum. Now that analytical chemists have learned how to detect it, should we be concerned if we find 10 or even 100 picograms of BDE209 in a gram our blood? We have to wonder if this chemical is being broken down in the body to smaller parts, which are known to be toxic. In the meantime, the detection of this flame retardant in the human body is sparking great interest in Europe and is the first step in getting to the bottom of the question of whether or not adverse effects are caused by BDE209 exposure. 
 
Heather Leslie