Investigating the spatial distribution of microplastics on Maltese sandy beaches

Abstract

This study investigates the concentrations, composition, and spatial distribution of large microplastics (LMPs) across three sandy beaches in Malta: Golden Bay, Ġnejna Bay, and Riviera Beach. Fieldwork involved systematic sediment sampling, followed by laboratory analyses to characterise particle size, colour, roughness, and polymer type, with additional granulometric analysis to examine links between sediment properties and microplastic retention. Data were processed using Microsoft Excel, QGIS, and Python, and interpreted through statistical and spatial analysis. Results showed that microplastic abundance was dominated by particles in the upper size range (4 – 5 mm), with polyethylene (PE) and polypropylene (PP) identified as the most common polymers. Colour analysis revealed yellow and grey as dominant, with site-specific variations in secondary colours. Roughness analysis indicated that primary microplastics (PMPs) were more prevalent than secondary ones, though Riviera Beach exhibited a smaller gap between the two categories. Spatial mapping highlighted heterogeneous distributions, with accumulation zones varying by site: Golden Bay displayed the highest densities, Ġnejna showed shoreline-focused hotspots suggesting stronger marine-based inputs, and Riviera recorded the lowest levels, consistent with its reduced proximity to urban and road-based sources. The findings provide baseline evidence of widespread microplastic contamination on Maltese sandy beaches, shaped by both terrestrial and marine sources, as well as beach morphology and sediment characteristics. By combining polymer identification, granulometry, and spatial mapping, this research contributes to a deeper understanding of microplastic transport and accumulation dynamics in coastal systems. It also underscores the importance of standardised monitoring protocols in line with the Marine Strategy Framework Directive (MSFD) to better inform management strategies and policy responses aimed at mitigating microplastic pollution in Malta’s coastal environments.