About Microplastic River Sampling Checklist

This open-access systematic review synthesizes laboratory findings on microplastic transport to provide practical guidance for field sampling design in rivers and transitional zones. Al-Zawaidah and Waldschläger analyzed 173 peer-reviewed laboratory studies published through August 2024, extracting critical processes that govern microplastic behaviour in freshwater systems and distilling them into actionable sampling recommendations.

The review addresses a persistent gap in microplastics science: field monitoring campaigns lack standardization, making data comparisons difficult and limiting understanding of environmental patterns. Laboratory experiments offer controlled conditions to isolate variables affecting transport, deposition, resuspension, and fate, but translating these findings into effective field protocols requires systematic synthesis. This work bridges that gap by identifying priority sampling locations, temporal windows, and particle characterization methods grounded in mechanistic research.

Key Features of Microplastic River Sampling Checklist

• Identifies priority sampling locations: salinity gradients, biologically active zones, and hydrodynamically diverse areas based on laboratory evidence of microplastic accumulation and behaviour.
• Temporal guidance tied to process duration: recommends sampling during and after hydrodynamic events (floods, high discharge) and biological shifts (algal blooms, biofilm formation) that alter transport and retention.
• Shape descriptor recommendations: advises recording at least three principal particle dimensions to enable translation into quantitative shape metrics suitable for transport modelling.
• Practical checklist for measurements: specifies essential data on microplastics (size, shape, polymer type, density, surface morphology, aging state), water properties, sediment characteristics, coexistent substances (organic matter, metals, pH), and environmental conditions.

Development and Validation

The review was conducted by the Hydrology and Environmental Hydraulics Group at Wageningen University and Research. Researchers used Web of Science to retrieve 3,474 articles on microplastic transport (search string: “microplastic* AND transport”), screened titles and abstracts to identify 371 candidates, and selected 173 studies meeting rigorous criteria: peer-reviewed publication in English, focus on laboratory experiments of transport and retention processes, and explicit particle size ranges between 1 μm and 5 mm. The screening process combined AI-assisted filtering (ChatGPT 4o) with manual validation; all final decisions and scientific interpretations were made through human review to avoid AI oversimplification and bias.

Data extraction captured objectives, flow conditions, microplastic properties (size, density, polymer type, shape), surface morphology, aging state, equipment, and key findings. The review evaluated aging protocols, aggregation methods, and particle preconditioning to assess study quality. Findings were synthesized thematically to answer three structured questions: where to sample, when to sample, and what measurements to report. Al-Zawaidah and Waldschläger, 2026, Microplastics and Nanoplastics demonstrates how laboratory mechanistic knowledge can inform field sampling strategy in rivers and estuaries.

Access and Data Availability

The article is published open access under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, permitting non-commercial sharing and distribution with appropriate attribution. The full text, supplementary tables (Tables S1–S3, Figure S1–S2), and structured data on the 173 included studies are available in the journal article.

Supplementary materials include the literature screening workflow, the AI-assisted data extraction framework and guiding questions, and detailed study metadata indexed by research focus (e.g., aggregation, settling, resuspension, biofouling, salinity effects). No downloadable dataset or code repository is provided; access to the full evidence base requires reading the published article and supplementary tables.

For complementary methods context, see Micro and NanoPlastic FRAGMentation in the ENvironmenT.

Why This Resource Belongs on Plastiverse

This resource directly supports the design and validation of microplastics field sampling campaigns in aquatic systems. Researchers planning river or estuarine monitoring can consult the practical checklist to select sampling locations informed by laboratory evidence of accumulation zones, define temporal windows around hydrodynamic and biological processes, and standardize particle characterization to enable comparison across studies. The shape descriptor guidance improves data quality for transport modelling by ensuring measurements are consistent and translatable into quantitative descriptors. By linking laboratory process understanding to field protocol design, this systematic review strengthens the scientific foundation of freshwater microplastics monitoring and supports efforts to generate comparable, ecologically relevant data across different river systems and research groups.