Characterization of Microplastics in Prapratno Beach Sediment

Catégorie : Détection et Caractérisation
Date :14 août 2020
Erceg, M.; Tutman, P.; Varezic, D. Bojanic; Bobanovic, A.
Kemija U Industriji-Journal of Chemists and Chemical Engineers : 69 (DocId: 5-6) 253–260.
Microplastics represent a major problem in the marine and coastal environment. In this work, microplastics from the sediment of Prapratno beach on the Peljesac Peninsula (Croatia) were analysed. Sampling and laboratory separation were performed according to the DeFishGear protocol (Derelict Fishing Gear Management System in the Adriatic Region). The microplastic waste from Prapratno beach sediment consisted of 116 specimens, which could be classified into 6 micro litter categories according to EU TG ML Master List (Fig. 1). Fragments were found to be the predominant category of microplastic waste from the sediment of Prapratno beach, followed by granules, films, pellets and foams, which were present in approximately the same number, while filaments were the least represented category (Fig. 2). The most important categories by mass were granules and fragments, followed by pellets, while films, foams and filaments made up a very small content of the total sample mass (Fig. 3). The numerical contents (Fig. 4), did not correspond to the mass contents (Fig. 3) of individual categories due to the different densities and thicknesses of the specimens in each category. Almost all the base colours were present in the analysed samples (Fig. 5), while 90.52 % of specimens were opaque (Fig. 6). The maximum dimension and surface area of each specimen was determined by Digimizer Image Analysis Software. Maximum dimensions in the range of 1-5 mm were observed in 52.59 % of the specimens, thus belonging to large microplastics (LMP), while 47.41 % of the specimens had maximum dimensions in the range of 5-20 mm, thus belonging to so-called mezzo litter. The distribution of specimen dimensions within LMP is shown in Fig. 8, and within mezzo litter in Fig. 9. The fraction of each category in the total sample surface area is shown in Fig. 10. These results are similar to the numerical fractions of categories, since the samples were generally in the narrow range of maximum dimensions, and thus their numerical fractions corresponded to their fraction in the total surface of the sample. Identification of plastic material was performed by infrared spectroscopy, HATR technique. The obtained spectra were compared with the spectra in the database (Fig. 11-13). The results showed (Fig. 14) that the microplastic waste from Prapratno beach was made of polyethylene (82.46 %), polystyrene (11.40 %) and polypropylene (6.14 %). These polymers came from plastic packaging since polyethylene, polystyrene and polypropylene are the most used polymers for plastic packaging.