<p>With the advancement of modern industry and rising living standards, environmental pollution has become an increasingly serious and widespread concern. In response, hydrogels have emerged as promising multifunctional materials to mitigate pollution due to their high porosity, tunable structure, hydrophilicity, and capacity to incorporate diverse functional groups, which enable both effective adsorption of pollutants and real-time detection through electrochemical sensing. Furthermore, their responsiveness to external stimuli, coupled with notable mechanical robustness and intrinsic self-healing behavior, positions them as versatile candidates for diverse environmental applications. This review outlines recent progress and key innovations in hydrogel-based materials for heavy metal adsorption while also addressing their integration into electrochemical detection systems. In addition, it briefly discusses hydrogel-based electrochemical sensors for detecting emerging contaminants, such as pesticides, dyes, and microplastics. Moreover, the emerging role of machine learning in guiding the rational design, intelligent development, and performance optimization of hydrogel-based systems is highlighted. The review concludes by discussing current limitations and outlining future research directions for their sustainable implementation in real-world technologies.</p> Graphical abstract <p></p>