Brominated flame retardants are a group of substances which have, in recent years, attracted considerable attention due to their potentially negative effects on man and the environment. Most intensely discussed today
are polybrominated diphenylethers (BDEs), because of their persistence and hydrophobic properties, that makes them amenable to bioaccumulation and biomagnification.1 An important environmental transformation process
of decaBDE (BDE209) may be photolysis2-9, that occurs even indoors3 or possibly at the surface or in the surface layer of flame retarded materials. Photolysis can be catalysed by photosensitizers (such as humic substances) or
can be inhibited by shading or by energy transfer to solids upon adsorption to surfaces. 4-6 Watanabe and Tatsukawa2 were the first to find that decaBDE, dissolved in n-hexane, debrominates rapidly under solar irradiation with a half-life of less than 0.5h, resulting in a large variety of lower brominated BDEs
(nona- to tetraBDEs) and brominated dibenzofurans (hexa- to monoBDFs). A photolytic half-life of decaBDE below 2 days has been observed even indoors in standard solutions in white glass3. Eriksson et al.7 performed photodecomposition experiments by a solar simulator with BDE congeners of different bromination degree in
methanol, tetrahydrofuran (THF) and methanol/water (80:20). They observed that di- to pentaBDFs were formed from decaBDE, whereas Ohta et al.8 did not report a formation of BDFs in their study of the photolysis of decaBDE in toluene by various light sources, including a tungsten lamp and sunlight, in spite of well resolved chromatograms with many debromination products. A thorough investigation of the pathways leading to BDFs is desirable, since the World Health Organization (WHO) concluded that BDFs are similar in their persistence and
toxicity to the chlorinated analogues; high toxicity or biological activity was found for 2,3,7,8-tetraBDF10 and has recently been demonstrated by Olsman et al. from bioassays for the photodebromination products of decaBDE11. Although a significant human exposure to BDEs is likely12, an analysis of the atmosphere
surrounding television sets in a test chamber did not detect any emission of BDFs from the flame-retarded rear portion of the cabinet13.
The present study investigates the products formed from photolysis of a saturated solution of decaBDE in THF, identifies BDFs from characteristic UV spectra and attempts to assign the degree of bromination and the
substitution pattern of individual congeners.