TY - JOUR

T1 - Qualitative environmental risk assessment of photolytic transformation products of iodinated X-ray contrast agent diatrizoic acid

AU - Rastogi, Tushar

AU - Leder, Christoph

AU - Kümmerer, Klaus

N1 - Copyright © 2014 Elsevier B.V. All rights reserved.

PY - 2014/6/1

Y1 - 2014/6/1

N2 - Recent studies have confirmed that the aquatic ecosystem is being polluted with an unknown cocktail of pharmaceuticals, their metabolites and/or their transformation products (TPs). Although individual chemicals are typically present at low concentrations, they can interact with each other resulting in additive or potentially even synergistic mixture effects. Therefore it is necessary to assess the environmental risk caused by these chemicals. Data on exposure is required for quantitative risk assessment of TPs and/or metabolites. Such data are mostly missing because of the non-availability of TPs and very often metabolites for experimental testing. This study demonstrates the application of different in silico tools for qualitative risk assessment using the example of photodegradation TPs (photo-TPs) of diatrizoic acid (DIAT), which itself is not readily biodegradable. Its photolytic transformation was studied and the photodegradation pathway was established. The aerobic biodegradability of photo-TPs under the conditions of an aquatic environment was assessed using standardized OECD tests. The qualitative risk assessment of DIAT and selected photo-TPs was performed by the PBT approach (i.e. Persistence, Bioaccumulation and Toxicity), using experimental biodegradation test assays, applying different QSAR models with several different toxicological endpoints and in silico read-across approaches. The qualitative risk assessment pointed out that the photo-TPs were less persistent compared to DIAT and none of them possessed any bioaccumulation threat. However, a few photo-TPs were predicted to be active for mutagenicity and genotoxicity, which indicate the need for further testing to confirm these predictions. The present study demonstrates that in silico qualitative risk assessment analysis can increase the knowledge space about the environmental fate of TPs.

AB - Recent studies have confirmed that the aquatic ecosystem is being polluted with an unknown cocktail of pharmaceuticals, their metabolites and/or their transformation products (TPs). Although individual chemicals are typically present at low concentrations, they can interact with each other resulting in additive or potentially even synergistic mixture effects. Therefore it is necessary to assess the environmental risk caused by these chemicals. Data on exposure is required for quantitative risk assessment of TPs and/or metabolites. Such data are mostly missing because of the non-availability of TPs and very often metabolites for experimental testing. This study demonstrates the application of different in silico tools for qualitative risk assessment using the example of photodegradation TPs (photo-TPs) of diatrizoic acid (DIAT), which itself is not readily biodegradable. Its photolytic transformation was studied and the photodegradation pathway was established. The aerobic biodegradability of photo-TPs under the conditions of an aquatic environment was assessed using standardized OECD tests. The qualitative risk assessment of DIAT and selected photo-TPs was performed by the PBT approach (i.e. Persistence, Bioaccumulation and Toxicity), using experimental biodegradation test assays, applying different QSAR models with several different toxicological endpoints and in silico read-across approaches. The qualitative risk assessment pointed out that the photo-TPs were less persistent compared to DIAT and none of them possessed any bioaccumulation threat. However, a few photo-TPs were predicted to be active for mutagenicity and genotoxicity, which indicate the need for further testing to confirm these predictions. The present study demonstrates that in silico qualitative risk assessment analysis can increase the knowledge space about the environmental fate of TPs.

KW - Chemistry

KW - Diatrizoic acid; Iodinated contrast media; Qualitative environmental risk assessment; Quantitative structure-activity relationships (QSAR); US EPA PBT profiler

UR - http://www.scopus.com/inward/record.url?scp=84897848777&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/9ae6c605-e7d3-3eda-b5eb-e477a74e69b6/

U2 - 10.1016/j.scitotenv.2014.02.139

DO - 10.1016/j.scitotenv.2014.02.139

M3 - Journal articles

C2 - 24662206

VL - 482-483

SP - 378

EP - 388

JO - The Science of The Total Environment

JF - The Science of The Total Environment

SN - 0048-9697

IS - 1

ER -