Ecological risk and pollution assessment of heavy metals in Jubail coastal sediments, Arabian Gulf: A multiscale assessment

Industrialization along the Arabian Gulf coast has intensified concerns about heavy metal (HM) accumulation in marine sediments, yet comprehensive site-based ecological assessments remain limited. This study investigates the distribution, contamination levels, and ecological risks of HMs and metalloids in 32 surface seabed sediments collected from offshore, midshore, and inshore zones around Jubail City, Saudi Arabia. Using a combination of geochemical indices (CF, EF, Igeo, PLI, and PERI) and multivariate analysis (PCA), the study distinguishes between lithogenic background inputs and anthropogenic sources associated with industrial discharge, port activities, and desalination outfalls. Results show that most metals were within global background levels. PCA results revealed two dominant controlling factors: a natural component (Fe, Mn, Cr, Ni) and an anthropogenic one (Cd, As, Cu, Zn). Pollution Load Index (PLI) suggested low to moderate contamination near industrial effluent outlets. The study provides a novel, integrated assessment framework that links geochemical patterns with ecological risk interpretation, offering baseline data for evidence-based coastal management in the Arabian Gulf. These findings underscore the importance of continuous, multi-seasonal monitoring and biological effect studies to evaluate the long-term ecological implications and inform sustainable industrial and marine spatial planning.