Transformation and ecotoxicological effects of iodinated X-ray contrast media

Abstract

Iodinated X-ray contrast media (ICM) such as diatrizoate, iohexol, iomeprol, iopamidol, and iopromide are commonly used in medical imaging for radiological visualization of a variety of anatomic structures. Because of their highly persistent nature and poor removal by conventional wastewater treatment, ICM can often remain unchanged after entering the environment or they are transformed into many different by-products in complex physical, chemical, and biological processes. Large amounts of ICM and their by-products are found in natural waters, groundwater, drinking water (up to 100 µg/L), and even in soil, where they can be a potential threat to the inhabitants of these environments. Because knowledge about the fate of ICM in various environments is dispersed and it concerns specific areas, the main purpose of this review is to summarize the available information about their occurrence, chemical and biological transformation/degradation, and toxicity to living organisms. The topics discussed particularly focus on mechanisms of ICM degradation/transformation in water using advanced oxidation processes and the biotransformation/biodegradation of ICM by microorganisms under different conditions, as well as the toxicity of ICM and their transformation by-products to humans and other organisms. Although environmental risk is not expected from the parent compounds of ICM, their continuous input to the water and the formation of toxic by-products may constitute a long-term potential risk for living organisms. Therefore, monitoring the transport and fate of ICM in various environments seems necessary.

Biodegradable Fiducial Markers for Bimodal Near-Infrared Fluorescence- and X-ray-Based Imaging

“…However, all compositions ensure the sufficient stability of the contrasting properties for X-ray-based imaging by at least a few months. The performed examinations proved that the tested materials undergo degradation and subsequent release of byproducts, and further, they were removed from the implantation site by known excretion paths. ,,− Moreover, the maximum amounts of radiopaque fillers, e.g., in 10 mm-long FM (approximately 10 mg in weight), are definitely lower than when administrated clinically or tested in other scientific reports; a single dose of iodinated contrast agents during an examination of a patient is up to 200 g . The content of BaSO 4 applied in well-tolerated pancreatic stents was approximately 30 mg (estimated from the geometry), and the mass of HAp granules inserted into thigh muscles of mice was 10 mg …”

Robust and Self‐Cleaning Electrochemical Production of Periodate

“…The degradation of iodine and chemotherapy agents was monitored using different analytical methods [62] . Methods with clear monitoring of degradation were used, according to each compound.…”

“…The degradation of iodine and chemotherapy agents was monitored using different analytical methods. [62] Methods with clear monitoring of degradation were used, according to each compound. Therefore, the concentration of each pharmaceutical had to vary to maintain a good sensibility of the respective detection.…”

Quantification of Active Ingredient Losses from Formulating Pharmaceutical Industries and Contribution to Wastewater Treatment Plant Emissions

“…At WWTP_large these compounds were sucralose, iomeprol, API_2, benzotriazole, and diclofenac; and at WWTP_small these were metformin, iomeprol, caffeine, acesulfame, and API_2. These compounds are all well-known to be present at high levels in WWTP effluents, , and many of them have weak biological activity, such as the artificial sweeteners and X-ray contrast agents . In contrast, compounds emitted by the FPIs are generally meant to be biologically active, and several have rarely been reported in domestic wastewater or at much lower concentrations.…”

“…These compounds are all well-known to be present at high levels in WWTP effluents, 1,26 and many of them have weak biological activity, such as the artificial sweeteners 33 and X-ray contrast agents. 34 In contrast, compounds emitted by the FPIs are generally meant to be biologically active, and several have rarely been reported in domestic wastewater or at much lower concentrations. This is especially true for three antibiotics (API_5, API_25, and API_33) and three compounds not authorized on the Swiss market (API_9, API_21, and API_22).…”