• General observations from sample analysis include: (i) Higher MP concentrations in the summer compared to winter across all environmental compartments; (ii) MP concentrations tend to be higher in rivers than in marine environments; (iii) PP is the dominant polymer in the surface and subsurface water, whereas PE and PTFE are more prevalent in sediments.
• Standardized matrix-specific hybrid analytical workflows harmonized sampling, sample treatment, isolation, and detection protocols to ensure reproducibility and inter-study comparability. Key advancements include the refinement of QCL-IR with optimized analyte transfer protocols using metal-coated (primarily gold) filters and reflective slides to improve recovery across various sample types and the development of an integrated thermoanalytical workflow, combining TD-GC/MS and Py-GC/MS to allow for the simultaneous identification of polymer types, quantification of MP mass and detection of co-occurring additives, all within a single analytical run.
• Guidelines for the extraction, purification, and detection of the smallest small microplastics (SSM) (≤ 20 µm – 1 µm) and nanoparticles (≤1000 nm – 30 nm) were established for water, suspended sediments, and biota samples.
• A portable, modular, and cost-effective Lab-on-a-chip microfluidic system was developed to sort by size and enable Raman-based identification of SSM and nanoplastics.
• A novel methodology was established for analyzing MP in mussels and other biota, using gold-coated filters and QC-LDIR transflectance analysis.
• To assess ecological risks, the plastic-to-zooplankton ratio (PZR) was calculated for the Mediterranean basin, providing new insights into the impact of MP on marine food webs and thus as a potential Good Environmental Status (GES) indicator for the MSFD.
• At the macro scale, the POS2IDON framework was enhanced for detecting suspected locations of floating marine plastic debris and other oceanographic features using high-resolution Sentinel-2 satellite imagery enhanced with machine learning algorithms.
• Adaptations from marine biodegradation standards led to the development of three novel limnic biodegradation test methods, using freshwater and sediments from lakes and rivers.
• Generated a comprehensive Life Cycle Assessment (LCA) framework for assessing biodegradable plastics, taking into consideration ecotoxicity factors.
• Developed the LABPLAS Project Toxicity Testing Scheme (LPTTS), a tiered framework designed to address two primary exposure pathways: (i) waterborne chemicals leached from plastics (Tier I), and (ii) plastic particles in contact with and/or ingested by organisms (Tier II).
• Developed five models to support the simulation and assessment of microplastic transport and fate:
(1) A detailed physics-based 3D time-marching (Eulerian) model for the North Sea, built in openTELEMAC, incorporating settling velocity-based Population Balance Equation (PBE) modelling. It accounts for buoyant and non-buoyant plastics, and is coupled with water motion and sediment transport calculations;
(2) A detailed physics-based depth-averaged 2DH Eulerian model for the Elbe Estuary (also in openTELEMAC) with particle size-based PBE modelling focusing on non-buoyant particles and coupled with water motion and sediment transport calculations. Findings from this model suggest that estuaries are also important sinks for river-transported MP;
(3) A 1D river basin model (ePLAS), allows fast calculations by solving only the mass balance for MP.
(4) A 1D vertical biogeochemical model for simulating the leachate transport from buried microplastics on the sediment bed.
(5) A foodweb exposure model, that estimates potential human health risks from fish consumption, based on MP concentration inputs from any of the above models. Initial assessments suggest that MP may pose a relevant role if humans' daily ingestion exceeds >1 mg of very small (1 µm) MP.
• Policy briefs were developed, addressing key issues such as tyre particle emissions, biodegradable polymers, plastic additives, and analytical methods for SMNP detection.
• Insights gained across the project’s various work packages informed the development of an action-oriented online course on micro- and nanoplastics in the environment.
