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Removal of the Iodinated X‑ray Contrast Medium Diatrizoate by Anaerobic Transformation
journal contribution
posted on 2015-12-17, 04:20 authored by Maria Redeker, Arne Wick, Björn Meermann, Thomas A. TernesThe
iodinated X-ray contrast medium diatrizoate is known to be
very persistent in current wastewater treatment as well as in environmental
compartments. In this study, the potential of anaerobic processes
in soils, sediments, and during wastewater treatment to remove and
transform diatrizoate was investigated. In anaerobic batch experiments
with soil and sediment seven biologically formed transformation products
(TPs) as well as the corresponding transformation pathway were identified.
The TPs resulted from successive deiodinations and deacetylations.
The final TP 3,5-diaminobenzoic acid (DABA) was stable under anaerobic
conditions. However, DABA was further transformed under air atmosphere,
indicating the potential for the mineralization of diatrizoate by
combining anaerobic and aerobic conditions. With the development of
a methodology using complementary liquid chromatography–electrospray
ionization–tandem mass spectrometry and liquid chromatography–inductively
coupled plasma–mass spectrometry techniques, all identified
TPs were quantified and the mass balance could be closed without having
authentic standards for four of the TPs available. The detection and
quantification of diatrizoate TPs in groundwater, in technical wetlands
with anaerobic zones, and in a pilot wastewater treatment plant established
for anaerobic treatment highlights the transferability and up-scaling
of the results attained by laboratory experiments to environmental
conditions.