Project “Deep SEE” aims to characterise to the microplastic pollution of the Maltese nearshore waters from an innovative perspective by targeting to shed more light on the dynamics of microplastic accumulation within the water column around the Maltese Islands.
This research project has been made possible through a joint collaboration between the University of Malta, Oceanography Malta Research Group (Prof Alan Deidun, Dr Adam Gauci, Ede Kossari Tarnik MSc Geoscience by Research), Zibel, Environmental NGO (Andrew Schembri, Arkadiusz Srebnik) and Eurofins Analytical Services Hungary Ltd. (Dr Gábor Bordós, Bence Prikler).
The same research has been part-supported by the Elisabeth Mann Borgese Bursary of the International Ocean Institute which has been awarded to Ede Kossari Tarnik for 2022-23.
The term microplastics (MPs) refers to a range of sizes (smaller than 5mm, which corresponds to the smallest pearl used in jewellery) of plastic fragments originating from waste that is released directly into the environment and or is directly degraded within the marine environment itself.
The NGO Zibel identified a possible modification of the Manta-net (50μm mesh size) setup, through which we could perform a stable sample collection at certain depths (without physical limit). We executed horizontal tow sampling by maintaining the Manta net at a stable depth (6-10±1m) in a parallel position, by setting up the perfect balance between the weighting of the frame of the manta-net and the speed of the tugboat to keep the net tight.
In parallel, surface MP samples were collected too, at the same locations, as references to be able to compare surface MP abundances and composition with mid-water ones at the same area. During the mid-water sampling, the same volume of water was filtered through the Manta net as at the surface and this was monitored through the flow meter attached to the net.
Two different sites were selected for the testing of the pioneer methodology: one impact site, which is subject to a sewage outfall, at Xgħajra, located off the south-eastern coast of Malta and a control site at Selmun, located off the north-eastern coast of Malta.
The collected samples were shipped to Eurofins Analytical Services Hungary Ltd., where the analytical support team has performed the full analytical evaluation. The plastic particles were analysed in two different size batches: 5000-1000 μm and 1000-50 μm. The latter were picked manually, captured by a digital camera first, then the chemical composition was analysed with FTIR-ATR.
Overall, the most abundant polymers recorded in our study were the Acrylic ones (42.9%). These are frequently used for lighting, electronics screen, automotive components and outdoor glazing in architecture and construction, PE-Polyethylene (17.3%) it is the most commonly-used plastic all over the world, mainly used as packaging material, PP-Polypropylene (15.7%) used in a wide variety of applications such as packaging, automotive parts, fibres and textiles and PS-Polystyrene (10.5%) mainly used as protective packaging (foam) or as plastic containers, bottles, lids.