Geomatics, geophysical and environmental analysis in Mellieha Bay (Malta)

Abstract

This study investigates the elemental composition and granulometry of sand samples collected from PB Mellieha Bay (Ghadira Bay), Malta, aiming to assess environmental quality to inform sustainable coastal management strategies. The primary objectives are to identify the presence and concentrations of elements using Energy Dispersive X-ray Fluorescence (EDXRF) spectroscopy, a method that provides detailed insights into elemental composition, and to characterize particle size distribution, particularly in relation to coastal erosion and sediment dynamics. Particle size analysis was conducted using the sieve analysis method with a mechanical shaker, where dried sand was passed through a series of standard sieves (1.18 mm, 710 μm, 600 μm, 300 μm, 150 μm, 106 μm) arranged in decreasing mesh size. This process involved agitating the sand for approximately 15 minutes to allow particles to pass through based on size. The residue on each sieve was weighed to determine particle size distribution, providing a detailed classification of sediment particles and insights into the granulometry of the bay's sediment. Results were represented as bar graphs to facilitate quick identification of trends, variations, and dominant particle sizes. In addition to EDXRF analyses, statistical analyses were performed using Kruskal-Wallis tests to determine associations between metal levels across different samples. Pairwise Correlation tests were also conducted to identify frequently co-occurring metals. Furthermore, Principal Components Analysis (PCA) was utilized to reveal patterns and intercorrelations within the data, supported by supplementary funnel graphs indicating the percentage abundance of metal compounds. The findings enhance understanding of the bay's sedimentary environment and its ecological and geological implications. This research is designed to aid in the overall perception of this coastal ecosystem and is particularly valuable for future monitoring and management efforts at PB Mellieha Bay.