Microplastics and nanoplastics in urban waters

Ever-expanding applications and the ineffective management of plastics have led to a large quantity of microplastics/nanoplastics (MNPs) polluting the environment. These tiny particles (< 5 mm) are widespread in different environmental matrices (soil, air, water), with urban waters shown to be an important source and sink of MNPs. Ubiquitous MNPs in urban waters have attracted growing public concern due to their high chemical persistence, accumulative effects, and potential toxic effects on living organisms, including humans. To this end, it is urgent to probe the distribution and fate of MNPs in urban waters and to understand the effect of MNPs on urban water systems. Furthermore, developing innovative remediation techniques is essential for realizing a plastic-free urban water goal. These emerging concerns related to MNPs pollution call for theoretical and technical solutions. This special issue was designated to provide a platform for sharing state-of-the-art findings, techniques, and insights in terms of helping address the MNPs issue in urban waters.