DETECTION OF MICROPLASTICS IN MARINE SEDIMENTS: RESULTS FROM THREE ITALIAN COASTS

The presence and dangerousness of microplastics (MPs) in aquatic environments is universally recognized. The MPs criticalities are tied to their small size (less than 5mm), which make most of the treatment processes used for other waste ineffective, to their persistence and poor degradability and to their presence in large and ever-increasing quantities. This research deals with the separation and identification of MP particles present within sediments of sea sand sampled in three different Italian coasts: Imperia (Liguria), Metaponto (Basilicata) and Villa San Giovanni, (Calabria). Comparison between sediment sampled from less frequented beaches and tourist ones were made too, to verify the relation with tourism or any other sources of MP pollution. The complexity of collecting and analyzing real sample, the proper counting and recognition of all MPs in the sample were deeply discussed. The importance of grain size classification and separation was highlighted [1]. The density separation method with saline solution (NaCl) was used to analyze the samples. In addition, a CaCl solution was tested to separate MP particles with higher density. Electrostatic separation method was tested too, separating the conductive fraction to the non-conductive (containing MPs) one. An increasing of MP content/g of sediment was obtained comparing the nonconductive fraction with samples subjected to densimetric separation with NaCl solution (reaching also a 82% of variation). This method could be used to reduce the volume of samples, optimizing the MP identification and counting; however, other tests could be carried out in the future taking into account that a loss of material due to the apparatus should be considered. Visual identification under microscope with a UV lamp was used to identify and count fluorescent MPs particles [2][3], subsequently verified with spectroscopy analyses using FTIR.