Determination of ten iodinated X-ray contrast media by solid-phase extraction and ultra-high performance liquid chromatography coupled with high-resolution orbitrap mass spectrometry

Far-UVC direct photolysis of iohexol and acetochlor: an experimental and mechanism study

Recently, the emission of 222 nm Far-UVC krypton chloride (KrCl*) excimer lamps, has gained widespread attention in the field of water treatment. This study compared the degradation kinetics of IOX and ACE under UV222 and UV254 irradiation. The results demonstrated that UV222 irradiation exhibited higher efficiency, increasing the removal rates of IOX and ACE from 72.46% and 19.31% to 100%, respectively. Probe experiments and electron paramagnetic resonance (EPR) spectroscopy were used to identify the major active species generated during UV222 irradiation ([HO•]ss = 2.74 × 10-13 M). In addition, the effect of pH, pollutant concentration, anions, and natural organic matter (NOM) on the photolysis of IOX and ACE was investigated. The results indicated that IOX and ACE exhibited minimal dependence on pH, and IOX showed low sensitivity to water matrix components. Finally, the electrical energy consumption of the IOX and ACE photolysis by UV222 and UV254 irradiation was evaluated. The results revealed that UV222 irradiation demonstrated superior economic benefits (EE/OUV222/IOX = 0.59951 KWh/L, EE/OUV222/ACE = 0.25443 KWh/L), effectively reducing treatment costs. This study elucidated the photolysis characteristics of IOX and ACE under Far-UVC irradiation, providing a reference for the selection of process conditions in practical applications.

Accurate prediction of pollution and health risks of iodinated X-ray contrast media in Taihu Lake with machine learning and revealing key environmental factors

Iodinated X-ray contrast media (ICM) are commonly detected at considerable concentrations in aquatic environments. The long-term pollution trends in ICM at the whole lake/river scale have not yet been investigated; therefore, the risks associated with ICM and the influences of environmental factors remain understudied. Herein, the occurrence and distribution of ICM in the surface water of Taihu Lake were comprehensively investigated. In addition, the accuracy and applicability of different machine learning models for predicting ICM pollution and associated health risk were compared using meteorological and water quality parameters as inputs. The results revealed that the Σ7ICM concentration ranged from 10.8 to 454.6 ng/L, exhibiting significant spatial and seasonal variations, which reflected the influence of hydrodynamics and climatic conditions. Among the nine models, the RF model achieved the most accurate prediction of ICM, with R2 ≥ 0.92. Via feature importance ranking and linear relationship analysis, TN, NH3-N, S275-295, PS, SUVA254, UV254, and pH were identified as important factors affecting ICM. This study provides a hybrid framework that includes environmental pollution prediction, health risk analysis, and key environmental factor identification for ICM, providing scientific techniques for the application of machine learning in the analysis of trace organic contaminants.

The Environmental Impact of Medical Imaging Agents and the Roadmap to Sustainable Medical Imaging

Medical imaging agents, i.e., contrast agents for magnetic resonance imaging (MRI) and radiopharmaceuticals, play a vital role in the diagnosis of diseases. Yet, they mostly contain harmful and non-biodegradable substances, such as per- and polyfluoroalkyl substances (PFAS), heavy metals or radionuclides. As a result of their increasing clinical use, these agents are entering various water bodies and soil, posing risks to environment and human health. Here, the environmental effects of the application of imaging agents are outlined for the major imaging modalities, and the respective chemistry of the contrast agents with environmental implications is linked. Recommendations are introduced for the design and application of contrast agents: the 3Cs of imaging agents: control, change, and combine; and recent approaches for more sustainable imaging strategies are highlighted. This combination of measures should engage an open discussion, inspire solutions to reduce pollution by imaging agents, and increase awareness for the impact of toxic waste related to imaging agents.

Occurrence and risk of iodinated X-ray contrast media in source and tap water from Jiangsu province, China

Microcontaminants in the water environment have received increasing attention due to their adverse effects on human health and wildlife. However, iodinated X-ray contrast media (ICM), a type of microcontaminants, have not yet been systematically documented in source and tap water. This study investigated ICM in water samples via a sampling activity from 25 drinking water sources and their corresponding 30 household taps in south-central Jiangsu Province, China. The total concentrations of ICM ranged from 14.2 to 138.5 ng/L in source water and 3.7 to 101.3 ng/L in tap water, respectively. The calculated average water treatment efficiency to remove ICM is 38.3% with large variation under different processes (ranging from 7.3% to 75.7%), which implied that ICM could not be effectively removed using current treatment technologies. By integrating other ICM into the predominant compound iohexol with relative potency factors, the health risks of total ICM through water consumption were assessed using the Monte Carlo simulation. The results concluded that the risk of ingesting ICM through tap water was not a major health concern for adults, teens, or children in the study area. Nevertheless, due to the lack of long-term toxicity data relevant for humans for ICM, this risk may be underestimated, which requires further research.