Methods for analyzing microplastics (MP) can be roughly divided into two categories; simple and budget friendly or more advanced and costly. Common to all existing methods is that they still require more development and validation. There is a need for cheap and fast methods for identifying a broad spectrum of MP with acceptable accuracy, but also advanced methods that can handle the detection of small MP and nanoplast (NP) of various polymer types in environmental samples. In ANDROMEDA, a combination of advanced techniques, such as µFTIR, Raman and SEM-EDX, should be optimized and used for characterization and quantification of MP and NP in the order of 1 µm, 0.2 µm and less. Particular focus will be given to types of MP that are challenging to detect, such as microfibers, paint flakes and tire wear particles.
The chemical, biological and physical impact and degradation of plastics in the environment will exacerbate the challenges of detecting the plastic. A large part of the project is therefore dedicated to methodology and application of methods for accelerated degradation of plastics in the laboratory. UV (sunlight), hydrolysis and thermal oxidation will be used for this purpose to obtain realistic plastic fragments and partially degraded materials for further testing in the project. Specific focus will be given to understanding the mechanisms of UV and microbial degradation of plastics, while looking at how these are affected by temperature, pH and high pressure. In addition, one will look at leakage of chemicals from the plastic under these conditions. In a master's project, fish and shrimp have been fed feed containing particles from car tires. The presence of leaked chemicals has been investigated in various tissues over time by the experiment. The leaching of several identified and unknown additives from car tire rubber was found in blood and liver from lumpfish over time by the use of high resolution mass spectrometry. The results from shrimp muscle and stomach contents were inconclusive due to an overshadowing matrix from the tissue samples. The use of pyGC/MS in digested tissue samples proved to not give good enough results to detect the uptake of rubber particles. In a follow-up master's project, started in spring 2022, crabs from a fjord with high car tires emissions were collected together with crabs from control areas without the same impact. In addition, mussels were also exposed to car tire particles in a laboratory experiment, under the same conditions as used for lumpfish and shrimp. This task is well underway with anticipation of the analyses in the coming weeks. Other plastic additives, such as UV substances, were measured in different plastic polymers that were exposed to natural UV over 12 months, laboratory based UV radiation for 12 weeks and high pressure experiments intended to mimic the pressure situation on the deep sea at 2000 m. These samples have been processed in the lab and are awaiting data evaluation. To investigate additive leaching from plastics eaten by marine organisms, we have also investigated UV substances, phthalate metabolites, OPFRs and PBDEs in various tissues of fulmars with findings of high amounts of plastic in the stomach. All these additives could have been detected, but only for PBDEs could we see a correlation between the amount of plastic absorbed and concentrations in tissues. New measurements are planned for 2023, which include fulmar tissue samples and plastic samples from the same individual. A key ongoing topic for the project is quality assurance. Project partners specializing in communication, dissemination and data management will ensure strong involvement of stakeholder groups and effective dissemination of project results. Dissemination through TV, radio, news stories, lectures and panel discussions has been carried out. Scientific dissemination has been carried out with 4 scientific publications, presentations at international conferences and several more are in the works.
Current methods for microplastic (MP) analysis can be divided into low-cost versus more advanced methods. ANDROMEDA recognizes that further development and validation is needed for both approaches. Low-cost methods are needed to identify a broad range of MP polymers. Advanced methods need further development to push the limit of detectability for smaller sizes of MP and nanoplastics (NP). Within ANDROMEDA, in situ MP detection, efficient sampling and cost-effective laboratory methods will be optimized to. Approaches will be based on hyperspectral imaging, chemical markers and fluorometric detection techniques to quantify and characterize MP and NP down to 1 µm, 0.2 µm or lower. Specific tasks will focus on challenging types of MP such as microfibers, tire wear particles (TWPs) and paint flakes. Quality assurance will be a central theme in all aspects of the project. Communication and data management will ensure strong stakeholder involvement and outreach of the project results. i