es8b01140_si_001.pdf (2.2 MB)
Anaerobic Transformation of the Iodinated X‑ray Contrast Medium Iopromide, Its Aerobic Transformation Products, and Transfer to Further Iodinated X‑ray Contrast Media
journal contribution
posted on 2018-07-11, 20:44 authored by Maria Redeker, Arne Wick, Björn Meermann, Thomas A. TernesThe
iodinated X-ray contrast medium (ICM) iopromide and its aerobic
transformation products (TPs) are frequently detected in the effluents
of wastewater treatment plants and in different compartments of the
aquatic environment. In this study, the anaerobic transformation of
iopromide and its aerobic TPs was investigated in water–sediment
systems. Iopromide, its final aerobic TP didespropanediol iopromide
(DDPI), and its primary aniline desmethoxyacetyl iopromide (DAMI)
were used as model substances. Five biologically formed anaerobic
TPs of iopromide and DAMI and six of DDPI, and the respective transformation
pathways, were identified. The TPs were formed by successive deiodination
and hydrolysis of amide moieties. Quantification of the iodinated
TPs was achieved by further development of a complementary liquid
chromatography (LC)–quadrupole time-of-flight mass spectrometry
(Q-ToF-MS) and LC–inductively coupled plasma – mass
spectrometry (ICP-MS) strategy without needing authentic standards,
despite several TPs coeluting with others. A database with predicted
anaerobic TPs of ICMs was derived by applying the transformation rules
found for the anaerobic transformation pathways of iopromide and diatrizoate
to further ICMs (iomeprol and iopamidol) and their aerobic TPs already
reported in the literature. The environmental relevance of the identified
transformation pathways was confirmed by identifying an experimental
TP and two predicted TPs using suspect screening of water taken from
anaerobic bank filtration zones.