The mechanisms of plastic transport in rivers remain an important knowledge gap in global plastic pollution research and management. We investigated how river flows and plastics' properties affect transport with a five‐point cross‐sectional field study in the Hillsborough River in Tampa (Florida, USA) using a 500‐µm Neuston net and an Acoustic Doppler Current Profiler. We conducted in‐depth analysis of water velocity profiles as well as plastics' concentrations and properties, determining advective, vertical, and lateral transport fluxes. Under calm flow conditions, advective fluxes were two orders of magnitude higher than lateral and vertical fluxes. Under turbulent conditions, enhanced particle exchange in the cross‐section resulted in a three to tenfold increase in lateral and vertical plastic fluxes. The impact of turbulence on plastic particles depended on properties such as size, shape, and composition. This study presents a unique assessment of flow conditions driving plastic pollution in an urban coastal river setting. Practitioners points Multipoint, cross‐sectional sampling and onsite flow profile collection should be adopted as a common practice for plastic field data collection to reduce uncertainty. Varying flow conditions affect the drivers of plastic transport in rivers. Advective surface fluxes govern plastic transport under calm flow conditions, while turbulent flow conditions enhance cross‐sectional mixing and particle exchange. Larger and more irregular‐shaped plastics are more affected by turbulence.

Field data on plastic pollution is extremely limited in Southeast Asian rivers. Here we present the first field measurements of plastic transport in the Mekong, based on a comprehensive monitoring campaign during the monsoon season in the confluence of the Mekong, Tonle Sap, and Bassac rivers around Cambodia’s capital (Phnom Penh). For improved accuracy in the estimation of plastic loads and distribution, we combined Neuston net multipoint cross-sectional water sampling with acoustic Doppler current profiler high resolution measurements. During the wet season, around 2.03 × 105 kg d−1 of plastic were released from Phnom Penh into the Mekong, equivalent to 89 g d−1 capita−1, or 42% of all plastic waste generated in the city. Most plastic mass moved downstream at the surface. A smaller portion of plastics is mixed deep into the water column, potentially retained in the rivers, breaking down and resuspending over time. Overall, plastic waste from Phnom Penh and transported by the Mekong is a significant contribution to Southeast Asia’s plastic release into the ocean. This pollution represents a crucial risk to people in the region, as their livelihoods depend on fisheries from these water bodies.

Metal deterioration via corrosion is a ubiquitous and persistent problem. Ångstrom-scale, atomically thin 2D materials are promising candidates for effective, robust, and economical corrosion passivation coatings due to their ultimate thinness and excellent mechanical and electrical properties. This review focuses on elucidating the mechanism of 2D materials in corrosion mitigation and passivation related to their physicochemical properties and variations, such as defects, out-of-plane deformations, interfacial states, temporal and thickness variations, etc. In addition, this review discusses recent progress and developments of 2D material coatings for corrosion mitigation and passivation as well as the significant challenges to overcome in the future.

Temporal and spatial variability are thought to drive river plastic transport, but most field data collections are limited to sporadic sampling at one location, constraining our ability to predict plastic pollution accurately. In this study, we assessed the impact of seasonal and longitudinal variability on river plastic loads collected during 18 months in Florida (USA). We used multipoint cross-sectional sampling, coupling a 500 μm Neuston net with an Acoustic Doppler Currency Profiler at three sites along the river, followed by laboratory measurements and Raman spectroscopy characterization. Annual plastic loads were highly variable, with median values of 1.67 × 109 particles (coefficient of variation [CoV] 89%) or 1.01 tons (CoV 203%) at the river mouth. The impact of urban pollution was evident and persistent in urban sections of the river, where plastic loads were found to be concentration-limited. Drivers of plastic pollution varied along the river; rainfall seasonality dictated transport in the least urbanized sub-watershed, but anthropogenic factors played a greater role in the urban sites. This study is one of the first to shed light on interconnections between plastics, river flow components, and rainfall. Understanding these mechanisms driving plastic pollution provides a tool to manage and reduce plastic in rivers.

Hierarchical heterostructures of two-dimensional (2D) nanomaterials are versatile platforms for nanoscale optoelectronics. Further coupling of these 2D materials with plasmonic nanostructures, especially in non-close-packed morphologies, imparts new metastructural properties such as increased photosensitivity as well as spectral selectivity and range. However, the integration of plasmonic nanoparticles with 2D materials has largely been limited to lithographic patterning and/or undefined deposition of metallic structures. Here we show that colloidally synthesized zero-dimensional (0D) gold nanoparticles of various sizes can be deterministically self-assembled in highly-ordered, anisotropic, non-close-packed, multi-scale morphologies with templates designed from instability-driven, deformed 2D nanomaterials. The anisotropic plasmonic coupling of the particle arrays exhibits emergent polarization-dependent absorbance in the visible to near-IR regions. Additionally, controllable metasurface arrays of nanoparticles by functionalization with varying polymer brushes modulate the plasmonic coupling between polarization dependent and independent assemblies. This self-assembly method shows potential for bottom-up nanomanufacturing of diverse optoelectronic components and can potentially be adapted to a wide array of nanoscale 0D, 1D, and 2D materials.