es400451w_si_002.pdf (3.08 MB)
Download fileBiotransformation of the UV-Filter Sulisobenzone: Challenges for the Identification of Transformation Products
journal contribution
posted on 02.07.2013, 00:00 by Rita Beel, Christian Lütke Eversloh, Thomas A. TernesThe
UV-filter substance Sulisobenzone (BP-4) is widely employed
in sunscreens and other personal care products. In the current study,
its behavior during biological wastewater treatment was investigated.
In contact with activated sludge BP-4 was degraded in aerobic batch
experiments forming at least nine transformation products (TPs). The
mass balance in the batch experiments was closed, as measurements
with LC-UV underlined that the quantity of the TPs was comparable
to the BP-4 quantity transformed. The chemical structures of the nine
TPs could be proposed based on accurate mass measurements by high
resolution mass spectrometry (LTQ-Orbitrap-MS), several fragmentation
experiments up to MS6 and synthesis of one TP. NMR analyses
of the main TP confirmed its proposed chemical structure. At the beginning
of the biotransformation of BP-4, a benzhydrol analogue was formed
due to the reduction of the keto moiety. Further reactions (e.g.,
oxidation, demethylation, decarboxylation) led to the formation of
extremely polar TPs. A biodegradation pathway was proposed based on
the TP structures identified and the sequence of the TP formation.
The isolated TPs exhibited higher toxic effects on Vibrio
fischeri than BP-4. The results contribute to a better general
understanding and prediction of the biotransformation of aromatic
sulfonic acids in WWTPs.