On July 26, 2013 the peer-reviewed journal Food Additives & Contaminants: Part A published a paper “Occurrence of brominated flame retardants in black thermocups and selected kitchen utensils purchased on the European market” (Samonsek and Puype 2013). The researchers from the Czech Institute for Testing and Certification at Zlin investigated the presence of brominated flame retardants (BFRs) originating from recycled waste electric and electronic equipment (WEEE) in black food contact articles. Samsonek and Puype investigated the presence of the following BFRs: decabromodiphenyl ether (decaBDE), tetrabromobisphenol A (TBBPA), tetrabromobisphenol A bis(2,3-dibromopropyl) ether (TBBPA-BDBPE), decabromodiphenylethane (DBDPE), polybrominated diphenyleters (PBDEs) and polybrominated diphenyls (PBBs). WEEE is recycled in cheap and low-quality products, which are not allowed for food contact since the contained BFRs are not authorized for use in food contact materials (FCMs) in Europe. From the 30 samples assessed, 19 were black stoppers and lids from thermocups. Two further red and green samples were used as controls, since no recycled materials were expected to be present. The remainder were kitchen utensils (spoons, stirring utensils, a cutting board, a pudding form, an oil funnel). From theses samples 49 test points were analyzed. The authors explain the focus on black plastic samples by aesthetic and technological reasons: Firstly, recycled polymers from WEEE retain a brownish color even when mixed with virgin polymer, which is not appealing for every application. Secondly, to the disadvantage of consumers, adding black pigment to polymers can hide the presence of BFR contaminated WEEE.
All samples were analyzed by means of X-ray fluorescence spectrometry (XRF) and thermal desorption gas chromatography coupled with mass spectrometry (thermal desorption GC-MS). Fourier transformed infrared spectroscopy measurement (FTIR) was used to identify the type of polymer FCMs were made of. Samsonek and Puype detected samples of FCMs containing BFRs; notably, the presence of BFRs in FCM violates European law (European Commission Regulation 10/2011/EC). At least one positive test point was found in 14 samples containing bromine levels ranging between 10 – 1922 mg kg-1. In 9 out of 14 bromine-positive samples PBDEs were detected, mainly technical decaBDE, composed of decaBDE-209 congener with minor quantities of nonaBDEs and octaBDEs. More recently introduced BFRs like TBBPA, TBBPA-BDBPE and DBDPE were found as well. No BTBPE, PBBs, HBCD, tribromotoluene or dibromotoluenes were found in the samples. The highest risk of BFR contamination was found for styrene-based polymers like ABS and high impact polystyrene (HIPS), followed by polypropylene-polyethylene copolymers (PP-PE). The authors explain this by the convenience of adding recycling fractions in the production of these materials.
Samonek and Puype conclude that the application of dark or black polymers in FCMs is critical, as about 40% of the measured samples are contaminated with BFRs. The authors state that the contamination stems from accidental or intentional adding of recycled WEEE with the aim to render the final product more cost efficient. In either case this violation of European law raises concern. As the present study is the first of its kind assessing BFR contamination of FCMs, the statistical base is still too small to draw a final conclusion concerning the overall risk of such contaminations for consumers.
As persistent, bioaccumulative, and toxic chemicals BFRs are suspected of causing neurobehavioral effects and to have endocrine disrupting properties. Some BFRs are also listed as hazardous by the Stockholm Convention. Recent studies have shown that BFRs cause cancer in experimental animals, likely by interfering with the endocrine system (NTP, 2013 and Gosavi et al., 2013).
The researchers therefore encourage further analysis of black plastic FCMs available on the market. They also point to the necessity for testing the migration of BFRs into food simulants. This latter point is of particular importance since many BFRs are lipophilic and thermocups are usually used for hot and partly fat containing beverages, e.g. milk. Both factors, heat and lipophilicity, are driving forces for potential BFR migration, implying a potential risk for human health. Finally, as the researchers remark, migration may also occur in contact with mucous membrane in the mouth while drinking.
Samsonek, J. and F. Puype (2013). “Occurrence of brominated flame retardants in black thermocups and selected kitchen utensils purchased on the European market”. Food Additives & Contamination: Part A (published online July 26, 2013).
NTP. 2013. “Tr-587: Technical report pathology tables and curves for tr587: Tetrabromobisphenol a (TBBPA)”. (U.S. National Toxicological Program website)
Gosavi A. et al. (2013),“Mimicking of Estradiol Binding by Flame Retardants and Their Metabolites: A Crystallographic Analysis”. Environmental Health Perspectives (published online August 19, 2013)