Assessment of heavy metals in surface seawater of Al Hoceima Bay, Northern Morocco

The present study provides the first comprehensive assessment of the distribution of heavy metals (Al, Fe, Mn, Co, Ba, Zn, Cr, Ni, As, Pb, Cd) in surface seawater of Al Hoceima Bay, Mediterranean Sea, Morocco, over an annual cycle. Water samples were collected in autumn 2022, winter, spring, and summer 2023 from fifteen sectors covering the entire bay. The analysis involved descriptive analysis, correlation matrices, PCA, and Cluster analysis. Concentrations of Pb and Cd were below detection limits, while Cr and Zn concentrations were below saltwater aquatic life preservation standards. However, As and Ni concentrations reached 49.55 mu g/L and 12.71 mu g/L respectively during autumn 2022 and summer 2023, exceeding international standards. The HPI indices, calculated using As, Cr, Ni, and Zn concentrations, indicated poor seawater quality during winter (HPI = 69.52) and spring (HPI = 75.08), and totally inadequate quality with likely adverse health effects during autumn (HPI = 114.64) and summer (HPI = 116.79). The study recommends continuous monitoring and integrated management to preserve the bay's biodiversity and ensure future sustainability.