Mineralogical and chemical characterization of Suez Bay surface sediments via multi-analytical techniques

The mineralogical and chemical characteristics of sediments from Suez Bay (SB) were investigated and correlated with the key water quality parameters. These include polycyclic aromatic hydrocarbons (PAHs), dissolved total phosphorus (DTP), biological oxygen demand (BOD), and total dissolved solids (TDS). Samples were collected from offshore SB sediments, and mass loss at different temperatures (120, 550, and 1000 °C) was analyzed. X-ray fluorescence (XRF) was used to determine the concentrations of 40 elements. X-ray diffraction (XRD) was applied to identify crystalline mineral phases, while Fourier transform infrared (FTIR) spectroscopy was used to characterize functional groups associated with organic matter and carbonate inputs. Major mass losses at 550 and 1000 °C were confirmed to result from the decomposition of organic matter and carbonate minerals, respectively. High enrichment factors and strong inter-element correlations were observed, indicating common sources for specific element groups. A positive correlation was observed between PAHs in sediments and vanadium and nickel, suggesting a petrogenic origin. Significant positive correlations between barium, copper, lead, and zinc likely reflect contamination from ship maintenance activities at the Kazak Hassan West site, south of the SB. In contrast, dissolved total phosphorus (DTP) in the water showed a negative correlation with silica, highlighting their distinct source origins. These findings reveal the distribution patterns of pollutants and their interactions with sediment mineralogy and chemistry, contributing to a clearer understanding of environmental pollution in SB. The results emphasize the influence of proximity to the Suez Canal and human activities on the geochemical behavior of the SB sediments and overlying waters.