RESEARCH ARTICLE Photochemistry of tetra- through hexa-brominated dioxins/furans, hydroxylated and native BDEs in different media

Abstract The aim of this study was to investigate (i) the behavior of native PBDEs during UV irradiation in different media, (ii) the possibility of their transformation into hydrox-ylated PBDEs in aqueous media, and (iii) the photochemistry/ levels of brominated dioxins/furans formed from hydroxylat-ed PBDEs. Debromination leading to the formation of a wide range of low-brominated congeners was the main path of photocatalyzed transformations of PBDEs. In organic solvents other than toluene, BDEs degraded in line with the pseudo first order kinetics (10–20 min half-life, depending on conge-ner type and reaction medium). Irradiated BDE 209 congener behaved quite differently than lower-brominated BDEs: de-tectable amounts of various bromo-benzenes were found. That suggests that UV irradiation of BDE 209 leads to cleavage of the ether bound between the congener’s aromatic rings. For-mation of bromophenyl bromo-methyl-biphenyl ethers or benzyl-bromophenoxybenzenes was observed in irradiated PBDE toluene-based solutions. The total concentration of OH-BDEs found in the reaction medium did not exceed 0.2 % of the initial precursor mass. Moreover, lower-brominated congeners detected in the reaction medium indi-cate subsequent debromination of OH-BDEs or hydro-debromination of the degraded congeners. Brominated di-oxins and low levels of furans were observed in samples con-taining OH-BDEs. The total mass of dioxins did not exceed 3.5 % of the initial precursor mass