How much does where we live and what we eat affect our exposure to flame retardants? This was the subject of a joint research project E&H researchers conducted with Dutch, Norwegian, Spanish and British colleagues, now published in Environment International. Flame retardants are chemical additives added to everyday plastic products such as synthetic textiles, furniture, electronic devices and cars. E&H researchers have been studying these chemicals for decades because over time they leach out of the plastic products and find their way into our indoor air, the global environment (from cities to the Arctic to the deep sea), food chains, and into our bodies. Many brominated flame retardants have been proven to be toxic to humans and wildlife, and several polybrominated diphenyl ethers (PBDEs) have finally been added to the Annex of toxic, persistent, bioaccumulative substances listed under the UN Stockholm Convention on Persistent Organic Pollutants.
Various types of brominated flame retardants have been detected in a number of avian and mammalian species. Most humans alive today have flame retardants in their blood. To find out more about the exposure to a specific flame retardant called BDE209 (also decabromodiphenyl ether, decaBDE), E&H researchers collaborated with an international consortium. The research team collected serum samples, lifestyle and diet information from European women from four countries: the Netherlands, the UK, Norway and Spain. E&H’s role was to guide the sampling process and analyze a flame retardant called decabromodiphenyl ether or BDE209 in the serum of the women to determine their actual exposure levels.
BDE209 came on the market in the late 1960s and is a high production volume (HPV) chemical. There is potentially a large amount of BDE209 present in any given household because of the high amounts added to consumer products (e.g. flame retardants make up on average 4-5 % of a living room couch’s weight). Therefore, people are exposed to this chemical on a daily basis, and it’s been postulated that diet and the types of consumer products present in one’s home may influence overall exposure. When BDE209 is metabolized by the body, toxic metabolites can also be produced.
Women volunteers (n=145) between the ages of 20 and 40 years were selected for this study in order to establish the range in systemic exposure and BDE209 body burdens of women around the age of their first pregnancy. Pre- and postnatal exposure to BDE209 important from a toxicological point of view, because exposure during sensitive early life stages can trigger adverse health effects later in life.
How exposed were these women?
The analyses of serum samples showed that the European women in this study had on average around 10 picograms of BDE209 per gram of serum. This is a very low amount of chemical that requires advanced techniques to detect and quantify. On average, women from the UK and the Netherlands had slightly higher levels of BDE209 in their serum than the Spanish and Norwegian women. In every country there were a few women who didn’t have any detectable BDE209 in their blood. The highest concentration observed in the entire study was 120 picograms of BDE209 per gram serum.
What happens to BDE209 in the human body?
BDE209 can be metabolized by humans, which explains the low levels of BDE209 measured in human serum in this study. Metabolism often involves partial debromination of the BDE209 molecule, creating lower-brominated metabolites. These molecules also cause toxicity, such as endocrine disruption and neurotoxicity. The human risk assessment of PBDEs should take such mixtures of chemicals into account.
Did lifestyle and diet impact women’s exposure levels?
It has been suggested that lifestyle and diet could be factors influencing BDE209 exposure, but no evidence was found in our study. The country of residence was the only variable that correlated with BDE209 levels in serum of the women in the study. In general, people today are limited in their choices to avoid exposure to a globally distributed, persistent environment contaminant such as BDE209. There are many diffuse sources of BDE209 that humans can be exposed to worldwide.
What’s next for BDE209?
In Europe, BDE209 is included in the Candidate List of Substances of Very High Concern (‘SVHC’) for possible inclusion in Annex XIV to the REACH Legislation. BDE209 as a chemical additive has been phased out of the production for most new products, though it will continue to have a long legacy in existing products, landfills and plastic waste and recycling streams, including e-waste. Incinerating consumer products containing BDE209 also releases some of the BDE209, but may also be a source of brominated dibenzofurans, which have toxicities on par with some dioxins and dibenzofurans. While production and use of BDE209 in Europe will be restricted from 2019 onwards some exceptions have been made. Until 2027, BDE209 is allowed to be used in the manufacture of aircraft in the EU, giving the industry additional time to switch to safer alternatives.
Reference: M. van den Berg, R. Houba, H.A. Leslie, R.F. Canton, C. Thomsen, G. Becher, M. Alvarez-Pedrerol, J. Sunyer Deu, M Steiner, M. van Tongeren, B. Brunekreef, J. de Boer (2017) Serum levels of decabromodiphenyl ether (BDE-209) in women from different European countries and possible relationships with lifestyle and diet. Environment International 107, 16-24.
Contact: Dr. Heather Leslie and Prof. Dr. Jacob de Boer