Fluorescence-based sensor for continuous monitoring of microplastic in sea water

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Cristofolini, Peter
Mühlebach, Lea
Markocic, Miha
Orawez, Georg
Shynkarenko, Yevhen
Martinez-Franzes, Elena
van Bavel, Bert
Cattaneo, Stefano
Microplastic contamination has been discovered in the most remote sections of the ocean and several other ecosystems, posing a major environmental threat to marine mammals and other species. The majority of microplastic particles are not biodegradable and accumulate in the food chain, posing a risk also to human health. The investigation of microplastic contamination in the ocean necessitates continuous monitoring to obtain high density data samples both spatially (to map the origin and effect of marine currents) and temporally (to understand long-term trends). Ideally, the data gathered should include detailed information such as particle counts, size fractions and composition. To date, most microplastic studies have relied on samples collected at specific times and locations and analysed in a research lab using techniques such as optical microscopy or Raman/FTIR spectroscopy. This approach provides valuable insights on the microplastic composition, but only a limited understanding of its spatial and temporal distribution. Within the framework of the Horizon 2020 project NAUTILOS, several compact and cost-effective sensors for autonomous continuous in-situ monitoring of ocean parameters are being developed. CSEM and NIVA are jointly developing an in-line microplastic sensor, capable of analysing marine microplastic in an automated manner. A sampler unit mounted onboard a ship filters the microplastic particles in the size range of 30-300 µm from sea water. Following the sampling, the microplastic samples are oxidized to remove biomaterials and subsequentially stained with a fluorescent dye that helps detecting the microplastics and assessing its type. Afterwards, the treated and stained microplastic samples are run through the detector unit, which is equipped with optical fluorescence detectors capable of detecting blue and UV fluorescence intensity in multiple spectral channels. By clustering time-series data from several sensors, we plan to measure and identify marine microplastic on-site and in real time. The microplastic sensor is planned to be deployed in a through-flow analysis system (FerryBox) installed on board of a ship-of-opportunity (ferry, cargo ship or research vessel) to establish consistent datasets of microplastic occurrences along the navigated route, for long-term monitoring and research. The microplastic data will be synchronised with GPS positions and other sensor data from the FerryBox. Subsequently, this data will be transmitted via satellite internet to a central server for further analysis.
Publication Reference
Precision Photonic Systems '23, FH OST in Buchs SG, 22nd-23rd October 2023
EU H2020 NAUTILOS Project