Microplastics (MPs) and nanoplastics (NPs) have emerged as persistent environmental pollutants, posing significant ecological and human health risks. Their widespread presence in aquatic, terrestrial, and atmospheric ecosystems necessitates effective removal strategies. Traditional removal methods, including filtration, coagulation, and sedimentation, have demonstrated efficacy for larger MPs but struggle with nanoscale plastics. Advanced techniques, such as adsorption, membrane filtration, photocatalysis, and electrochemical methods, have shown promising results, yet challenges remain in scalability, cost-effectiveness, and environmental impact. Emerging approaches, including functionalized magnetic nanoparticles, AI-driven detection, and laser-based remediation, present innovative solutions for tackling MP and NP contamination. This review provides a comprehensive analysis of current and emerging strategies, evaluating their efficiency, limitations, and future prospects. By identifying key research gaps, this study aims to guide advancements in sustainable and scalable microplastic removal technologies, essential for mitigating their environmental and health implications.

The increasing use of nanoparticles (NPs) in various industries has intensified research into plant–NP interactions. NP properties significantly impact their cellular uptake and plant effects, highlighting the need for advanced monitoring techniques to understand their influence on plant growth and seed germination. This study uses biospeckle optical coherence tomography (bOCT) to investigate the size-dependent effects of zinc oxide (ZnO) NPs and microparticles (MPs) on lentil seed internal activity, visualizing dynamic changes under ZnO particle stress. ZnO was selected for its agricultural relevance as a micronutrient. Lentil seeds were submerged in ZnO particle dispersions (<50 nm, <100 nm, 5 μm, 45 μm) at concentrations of 0 (control), 25, 50, 100, and 200 mg/L. OCT structural images were obtained at 12.5 frames per second using a swept-source OCT (central wavelength 1.3 μm, bandwidth 125 nm, sweep frequency 20 kHz). OCT scans were performed before immersion (0 h) and 5, 10, and 20 h after lentil seed exposure to particle dispersion. The biospeckle image, representing dynamic speckle patterns characteristic of biological tissues, was calculated as the ratio of standard deviation to mean of 100 OCT structural images over 8 s. Biospeckle contrast was compared 0, 5, 10, and 20 h post-exposure. ZnO NPs <50 nm and 100 nm negatively impacted lentil seed biospeckle contrast at all concentrations. In contrast, 45 µm ZnO MPs significantly increased it even at 100 mg/L, while 5 μm MPs decreased biospeckle contrast at higher concentrations. bOCT results were compared with conventional morphological (germination percentage, growth, biomass) and biochemical (superoxide dismutase, catalase, and hydrogen peroxide) measurements. Conventional methods require one week, whereas bOCT detects significant changes in only five hours. The results from bOCT were consistent with conventional measurements. Unlike standard OCT, which monitors only structural images, bOCT is capable of monitoring internal structural changes, allowing rapid, non-invasive assessment of nanomaterial effects on plants.

Significant concerns regarding the impact of copper (Cu) and copper oxide (CuO) nanoparticles (NPs) and microparticles (MPs) on plant systems have been brought to light through the growing use of these materials in industry and agriculture. The properties of NPs are critical in determining their uptake by plant cells and the ensuing effects on plant physiology. This emphasizes the need for accurate monitoring techniques to determine the impact caused by NPs on seed development and plant growth. This study uses foliar exposure at 0 and 100 mg/L, as well as seed exposure at 0, 25, and 100 mg/L, to explore the effects of Cu (<10–25 μm; 25 nm) and CuO (<10 µm; <50 nm) NPs and MPs on lentil (Lens culinaris). Biospeckle optical coherence tomography (bOCT) was employed to monitor internal physiological activity in real time, non-invasively—capabilities that static imaging methods, such as OCT, are unable to provide. Results showed that exposure to Cu and CuO NPs led to significant reductions in biospeckle contrast, indicating heightened physiological stress, while MPs generally produced minimal or even positive effects. These early changes detected by bOCT within just 6 h of exposure were consistent with traditional morphological and biochemical assessments—such as germination rate, growth, biomass, and catalase activity—that typically require several days to detect. The study demonstrates that bOCT enables the rapid, functional assessment of nanomaterial effects, including those resulting from foliar exposure, thereby offering a powerful tool for early and non-destructive evaluation of plant responses to engineered particles in agricultural contexts.