Multi-indicator appraisal of potentially toxic elements pollution in the southeastern Mediterranean Sea harbours: Unraveling sources, acute ecotoxicity and health risks

Abstract

This study evaluates contamination levels and ecological risks of potentially toxic elements (PTEs) in sediments and seawater across three Egyptian harbours: Sidi Krir, El-Dikhaila, and Western Harbour. Western Harbour exhibited the highest PTE concentrations, with Zn (134.93 mg/kg), Cu (88.38 mg/kg), Pb (103.6 mg/kg), and Cd (1.21 mg/kg) surpassing other sites by up to 4-fold. Ecological risk assessments revealed considerable hazards, particularly for Cd (Er = 121.67), and moderate to substantial risks for Cu and Pb (mHQ = 1.21–2.37). Partition coefficients indicated Cu and Pb mobility from sediment to water, with Pb exceeding China's Grade I thresholds in the water column. Multivariate analysis linked PTEs to industrial and shipping activities. Acute risk quotients identified Cu (RQ > 100 for invertebrates) and Zn (RQ > 10 for algae) as primary toxicants. Cadmium posed a lifetime cancer risk (LCR > 10 −4 ) for children via ingestion, highlighting significant ecological and health concerns. • Integrated risk ranked harbours: Western Harbour > El-Dikhaila Harbour > Sidi Krir Harbour. • Cu, Pb, and Zn tend to partition into seawater (3 < LogK d < 4), while Cd remains in the dissolved phase ( LogK d < 3). • Risk quotients ( RQ MEC/PNEC and RQ STU ) revealed acute ecological risks to invertebrates>algae>fish. • Sediment posed minimal health concerns ( THQ < 1; LCR < 10 −6 ). • Seawater showed low non-carcinogenic risks ( THQ < 1), but elevated carcinogenic risk from Cd ( LCR > 10 −4 ).