Chemical Characterization and Grain Size Distribution of Sediments along the Red Sea Coast

This study presents the chemical composition and grain size distribution of surface sediments collected from twenty-one sites along the Egyptian Red Sea coast. All sediment samples were subjected to analyses for grain size fractions, carbonate content, total organic matter, pH, electrical conductivity, and concentrations of exchangeable cations. The overall textural types of these sediments were mostly sandy, with the total sand fraction exceeding 90%, indicating a high-energy depositional environment. Fine and medium sand fractions dominated, while silt and clay fractions were minimal. The CaCO₃ content varied between 9.91 and 23.33%, reflecting moderate carbonate enrichment, while TOM ranged between 0.70 and 2.78%, indicating low organic accumulation. Sediment pH values ranged from 7.40 to 8.69, confirming generally alkaline conditions, while the variable salinity levels among sites were revealed by EC ranging from 3580 to 7987 µS/cm. Exchangeable cations in sediments demonstrated significant spatial variability, where sodium showed the highest concentrations, particularly in sites exposed to marine influence. These results point out the dominance of sandy carbonate sediments along the Red Sea coast and the marked heterogeneity in physicochemical characteristics, which are closely related to geomorphological settings and hydrodynamic processes. The findings provide preliminary data that will be essential in future environmental monitoring and coastal management in this ecologically sensitive region.