# Iodinated Contrast Media—From Clinical Use to Environmental Concern and Treatment Possibilities

## TL;DR

This paper discusses how iodinated contrast media used in medical imaging can harm the environment and explores advanced methods to break them down safely.

## Contribution

The paper reviews advanced oxidation processes for treating iodinated contrast media and highlights challenges in scaling these methods.

## Key findings

- Advanced oxidation processes effectively degrade iodinated contrast agents in laboratory settings.
- Incomplete mineralization and by-product formation remain challenges for large-scale implementation.
- Future research should focus on optimizing treatment conditions and assessing by-product toxicity.

## Abstract

Iodine-based contrast agents (ICMs) are crucial substances in medical imaging because of their potent X-ray characteristics and chemical stability. However, their persistence and poor removal in conventional wastewater treatment have led to increasing environmental concern. Although ICMs exhibit low acute toxicity, their transformation during water disinfection can generate iodine-based disinfection by-products (I-DBPs), like iodo-trihalomethanes, which display notable cytotoxic, genotoxic, and ecotoxic effects and compromise drinking water quality. Advanced oxidation processes (AOPs) have become promising methods for breaking down persistent ICMs and limiting the formation of I-DBPs. Techniques including ozonation, UV/H2O2, UV/chlorine, photocatalysis with TiO2, Fenton reactions, and electrochemical oxidation utilize highly reactive radicals to decompose persistent compounds like iopamidol, iohexol, iopromide, and diatrizoate. Despite high degradation efficiencies under laboratory conditions, limitations such as incomplete mineralization, secondary product formation, and elevated operational costs hinder large-scale implementation. Future research should focus on optimizing AOP conditions under realistic water matrices, evaluating by-product toxicity, and developing cost-effective hybrid systems. Advancing these technologies is critical to reducing the environmental burden of ICMs and safeguarding aquatic ecosystems and public health.