posted on 2016-02-19, 11:50authored byPaul Bendig, Walter Vetter
Bromophenols
(BPs) are both man-made industrial compounds and naturally
produced secondary metabolites of algae and sponges. This study explored
the formation of BPs by UV irradiation of polybrominated diphenyl
ethers (PBDEs). Simulated sunlight (10–80 min) and natural
sunlight irradiations (5 days) of BDE-153, BDE-154, BDE-183, BDE-196,
and technical octabromodiphenyl ether (DE-79) generated hydrodebrominated
PBDEs along with up to 0.7–4 mass % BPs. UV absorption spectra
were recorded to show that the para-substituted PBDEs and BPs are
those predominately transformed because this structural feature causes
a significant bathochromic shift of λmax to higher
wavelength. A decrease of higher brominated BPs in favor of lower
brominated BPs was observed with time. All possible substitution patterns
on the BPs formed by the cleavage of the parent PBDEs and respective
hydrodebromination products were observed. The main di- and tribromophenols
detected were 2,4-diBP > 2,5-diBP and 2,4,6-triBP > 2,4,5-triBP
on
average. The irradiation conditions were similar to real-world scenarios
and emphasized the environmental relevance of these photolysis products
of PBDEs. The meta-substituted BPs can be used as markers to distinguish
photolytic PBDE transformation products from naturally produced BPs,
which exclusively feature bromo-substitutents in ortho- and para-positions.