Assessment of Radioactivity and Heavy Metal Pollution Levels in the Coastal Sediments in the Red Sea Region of Sharm El Luli, Egypt

Abstract

This study investigated the contents, spatial distribution, and ecological and health risks of nine metals in 19 coastal sediments from Sharm El Luli area, Red Sea. Metals followed a decreasing pattern: Fe > Ba > V > Cr > Zn > Pb > Cu > Ni > Co. Pb, Cr, and V exceeding the Canadian soil quality guidelines and earth crust backgrounds. Levels of Pb, Cr, Ni, and Zn in Sharm El Luli’s sediments have surpassed their respective Effect Range Median (ERM) values, suggesting potential adverse effects on local biota. Factor analysis results showed significant loads of Ba, Co, V, pH, and TOM% (F1: 21.3%), Cu, Cr, Sand%, and Mud% (F2: 18.6%), and Pb, Ni, Zn, Fe, and Gravel% (F3: 18%). Contamination factor values indicated low (Ba and Fe), moderate (Co, Cu, Cr, Ni, and V), considerable (Pb), and high (Zn) contamination. Geo-accumulation index of all metals indicated extremely contaminated sediments (I_geo > 5). The Potential ecological risk index of metals examined showed low risk (PERI < 150). Mean effects range median quotient (MERMQ) value (1.08) showed medium–high priority risk (0.51 < MERMQ ≤ 1.5), and Toxic risk index showed moderate toxicity risk. Non-carcinogenic risk index (HI) values indicated no chronic risk (HI < 1), and total carcinogenic risk (TCR) values were below the safe limit (1 × 10⁻⁴). The distribution of natural radioactive elements in sediments was also assessed. Mean ⁴⁰ K, ²²⁶Ra, and ²³²Th activity of sediments were 23.32, 24.57, and 241.83 Bq/kg, respectively, being lower than the recommended global limits. The heavy minerals detected are pyrite, ilmenite, and beryl. The study underscores the urgent need for comprehensive management strategies to mitigate environmental hazards from heavy metal pollution in coastal sediments, requiring ongoing scientific investigation and cooperation, which will play a crucial role in protecting the Red Sea's marine ecosystem.