First full investigation of levels of microplastics on sandy beaches in Malta

Abstract

This paper will report on the first full investigations on the level of occurrence and qualitative/quantitative profiles of microplastics, MP, (1-5mm) in a number of saudy beaches in Malta, (Central Mediterranean). Five popular beaches were investigated, including Ghadira Bay, Golden Bay, St. George's Bay, Ghajn Tuftieha Bay and Pretty Bay. Samples for all bays were collected in August 2015, while further detailed sampling was carried out for the last two bays in summer and in winter of2016. Sampling protocol was adopted from Galgani et aI., (2013). For all locations, samples were collected from strandline and then at 10m up shore at surface (top 5 cm). For Ghajn Tuffieha and Pretty Bay, samples were also collected from a 40cm depth. MP were extracted from sand through wet sieving, and then sorted and characterized according to size, colour, shape, and polymer type. Several parameters including degree of sea exposure and sand properties were reeorded. Full beach profiles for all locations are available. Identification of polymer type was carried out by means of qualitative density tests. In summer of 2015, the highest levels of MP were reported in Pretty Bay at 10.81 items/1000cm of wet sand with the lowest being in Ghajn Tuffieha, at 0.72 items/1000 cm. In general, levels ofMP in the dry season were found to be higher than those recorded in the wet season (winter), Higher MP concentration was recorded at 10 m up-shore as opposed to the strandline. Furthermore, surface sands comained a higher concentration of MP when compared with the subsurface sediments: though this was not was not the case at Pretty Bay in winter. These results are interpreted in terms of different beach profiles, beach dynamics, sand properties and potential sources of MP. The local level of occurrence of MP seems to be lower when compared to other European locations studied so far. The fact that in this study, MP below 1mm were not included in the data, as well as the lack of rivers in the Maltese isimlds, regular beach clean ups and other factors may explain this. Data on the characterisation of MP found are provided. For example, polyethylene and polypropylene were the most common polymers recorded at Gnajn Tuftleha Bay whereas polyethylene and paint fragments were the most common 'MP recorded at Pretty Bay, This investigation is a contribution to our knowledge of how levels of MP in sandy beaches may be affected by sand properties and dynamics, beach profiles and other factors.was no! the case at Pretty Bay in winter. These results are interpreted in terms of different beach profiles, beach dynamics, sand propel1ies and potential sources of MP. The local level of occurrence of MP seems to be lower when compared to other European locations studied so far. The fact that in this study, MP below Irnm were not included in the data, as well as the lack of rivers in the Maltese isimlds, regular beach clean ups and other factors may explain this. Data on the characterisation of MP found are provided. For example, polyethylene and polypropylene were the most common polymers recorded at Ghajn Tuftleha Bay whereas polyethylene and paint fragments were the most common 'MP recorded at Pretty Bay, This investigation is a contribution to our knowledge of how levels of MP in sandy beaches may be affected by sand properties and dynamics, beach profiles and other factors.