Potentially toxic element contamination and ecological risk assessment in surface sediments of Attaqa port, Gulf of Suez, Egypt

This study presents the first systematic baseline assessment of potentially toxic element (PTE) contamination and ecological risk in surface sediments of Attaqa Port, a semi-enclosed harbour in the Gulf of Suez, Egypt. Fifteen surface sediment samples were analysed for Fe, Mn, Zn, Cu, Ni, Pb, and Cd concentrations and evaluated using an integrated suite of pollution indices, sediment quality guidelines (SQGs), and multivariate statistics. Mean concentrations followed the order Fe (14,627.93 mg/kg) > Zn (307.23) > Mn (162.28) > Cu (85.58) > Pb (79.78) > Ni (19.44) > Cd (0.71). Enrichment factors (10–50) and geo-accumulation index values (0.5–4) indicated moderate to strong anthropogenic enrichment of Pb, Zn, Cu, and Cd, whereas Ni and Mn retained background concentrations. Mean Zn exceeded both the TEL and PEL thresholds, and mean Cu and Pb exceeded the TEL. Contamination factor analysis using local minimum concentrations as the site-specific reference baseline identified very high contamination for Cu (CF = 8.24) and Zn (CF = 7.59), and considerable contamination for Pb (CF = 5.33) and Cd (CF = 4.47). The individual ecological risk factor for Cd (Er = 134.0) indicated considerable risk, Cu showed moderate risk (Er = 41.19), and the integrated Potential Ecological Risk Index for the study area (PERI = 228.8) corresponded to moderate ecological risk. Multivariate analyses partitioned lithogenic (Fe–Mn–Ni) from anthropogenic (Pb–Zn–Cu–Cd) PTE sources, with sediment texture and organic matter explaining 54.7% of spatial variance. These findings provide a transferable baseline for environmental monitoring of semi-enclosed port systems along the Gulf of Suez coast.