Monitoring microplastics in the norwegian environment

Norway's first microplastics monitoring program, MIKRONOR, began in 2021. Microplastics have been sampled and analyzed in various environments and matrices, including marine, limnic, and urban areas, samples taken in waters, sediments, biota, and air. The results from over 600 individual samples will be presented. One of the main findings in the 2023 monitoring program was the particularly high numbers and concentrations of particles in the inner Oslo Fjord. This included a high count of microplastic particles, a high mass concentration of plastic polymers, and notably high mass concentrations of tire wear particles in the sediments of the inner Oslo Fjord. Tire wear particles were also found in considerably high concentrations in blue mussels from the same area. The concentrations of tire wear particles in the sediments of the inner Oslo Fjord were similar to previous measurements in soils near roads (Rødland et al., 2023). Notably, the highest concentrations observed in the inner Oslo Fjord, around 20 mg/g dw, align with the highest values from Rødland's study (2023), indicating the accumulation of tire wear particles in high concentrations in the fjord sediments. Monitoring microplastics is challenging, as the research field is still evolving, and fully harmonized methodologies are not available. When deciding on the survey design, choice of methods, and reporting of results, we recommend that monitoring efforts refer to the Technological Readiness Level scale developed within the EUROqCHARM project and published in Aliani et al. (2023). Governmental monitoring of microplastics cannot be put on hold due to a lack of standardization but must be an integrated part of the development process in the microplastic research field. However, the design of sampling programs and interpretation of results must be seen in the light of the maturity state of the methods. Also see: https://micro2024.sciencesconf.org/559509/document