Methods for analysing microplastics (MP) can be broadly 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 the identification of a wide range MP with acceptable accuracy, but also advanced methods that can handle the detection of small MP and nanoplastics (NPs) of various polymer types in environmental samples. In ANDROMEDA a combination of advanced techniques, such as µFTIR, Raman and SEM-EDX, is 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 particles from tyre wear.
The chemical, biological and physical impact and degradation of plastics in the environment will exacerbate the challenges of detection of 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 project, fish and shrimp have been fed with feed containing particles from car tires. The presence of leached chemicals has been investigated in various tissues over time by the experiment. Hatching of several identified and unknown additives in car tyre rubber was found in the blood and liver of lumpfish over time. The results from shrimp muscle and stomach contents were unclear due to an overshadowing matrix from the tissue samples. In a follow-up master project, crabs from a fjord with high car tire emissions were collected along 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 lumpfish and shrimp. This assignment was submitted in May 2023 and resulted in a grade A for the student. We were able to demonstrate that mussels are also capable of absorbing chemical substances from car tyres, rubber granules. We found the same substances in mussels taken in several places along the Norwegian coast. Other plastic additives, such as UV substances and additives used in rubber in car tires, were measured in various plastic polymers that were exposed to natural UV light over 12 months, artificial UV radiation under laboratory conditions in parallel with high-pressure experiments to mimic the pressure situation in the deep sea at 2000 m. To investigate the leaching of additives from plastics eaten by marine organisms, we have also investigated UV substances, fthallate metaboliters, OPFRs and PBDEs in various fulmar tissues 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 absorbed plastic quantity and concentrations in tissues. New measurements in 2023, which included fulmar blood samples and plastic samples from the same individual were carried out by a french master student. Our findings have been used to advice regulators and other stakeholters as AMAP and the Norwegian Environmental Agency. The project manager stayed for 6 months as a guest researcher at MIO in France, which is the project manager of the main project ANDROMEDA JPI Ocean. In order to test new sampling methods for MP, NILU was responsible for testing air sampling rescue for MP in air. Both active and passive air sampling methods were developed and tested both at NILU in Tromsø, MIO near Marseille and on the second ANDROMEDA cruise in the Atlantic in spring 2023. So far, we have published our results in 8 scientific publications and 4 master's theses with more in progress.
ANDROMEDA did mahorly improve our ability to study and monitor the environmental distributions, fate and effects of MP and NP in the marine environment, contributed significantly to establishing the necessary knowledge base for conducting risk assessment. The project developed analytical methods to analyze MP in situ or by field measurement, in our case in expsoded marine species and wild life. We suceeded to also to develop and optimize cost-efficient samplers and cost-effective laboratory analysis methods for the analyses of MP in air. ANDROMEDA did achieve considerable impact by providing much needed advanced methods for the analysis of MP smaller than 10 µm, including challenging types of MP (e.g. fibers and TWPs). Another key outcome of ANDROMEDA was the contrbution to a platform for conducting accelerated degradation of plastic at the laboratory scale, including the leaching of additive chemicals over realistic time-scales. ANDROEMDA furtherd our understanding about the leachin capabilities of numerous additives under various enviornmentally relevant conditions, inclusing within organisms.
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