Waterborne Nanoplastics and Microplastics: Analytical Advances, Modelling, and Future Directions

Abstract

Plastics’ persistence throughout their life cycle has imposed a global burden of nano- and microplastics in aquatic systems. This Frontier Review consolidates recent advances in analytics, machine learning, and fate and transport modelling, and sets a practical agenda for decision-ready measurements. Analytical breakthroughs enable chemically specific imaging at tens-of-nanometre resolution using sub-micron vibrational methods, while hyperspectral stimulated Raman scattering delivers rapid single-particle chemical mapping. Emerging holography techniques provide in-situ, real-time physicochemical characterization, capturing 3D size, shape, surface coatings, and other features and can distinguish nano- and microplastics from other particles within milliseconds. Complementary innovations, including label-free photonic and electrochemical sensors and separation workflows coupled with mass spectrometry, extend polymer specificity and quantification in complex waters. Across these platforms, machine learning accelerates denoising, feature extraction, automated classification, and imaging throughput. Yet, performance remains constrained by biased or limited datasets, label noise, and domain shifts across instruments, matrices, and weathering states. Modelling frontiers require adaptation for nanoplastics, where Brownian diffusion, rapid aggregation, and dynamic eco-coronas govern transport and water–sediment exchange. Existing nanomaterial models offer transferable scaffolds when re-parameterized for nanoplastic behaviour. To enable interoperable, validated, and scalable systems, we recommend: (a) universal Report Nano- and Microplastic Analytics checklist aligned with International Organization for Standardization (ISO) guidance for diverse media; (b) standard reference materials and blinded interlaboratory trials; (c) open, versioned datasets; (d) machine-learning tasks with fixed splits and uncertainty reporting; (e) routine, end-to-end uncertainty quantification and traceability; (f) field testbeds integrating sensors, analytics, and fate and transport models to deliver policy-relevant indicators with calibrated confidence. Together, these steps will transform fragmented efforts into robust, decision-ready frameworks for safeguarding water quality in the age of nanoplastics.