Assessment of heavy metal contamination in the sediments of Marchica Lagoon: Sources, ecological risks, and mitigation strategies

¹ Laboratoire de la Lagune Marchica de Nador pour les Sciences Bio-Géo-Physique et Environnement (LOLMAN-BGPE), Faculté Pluridisciplinaire de Nador, Université Mohamed Premier-, Maroc.
² Fishing laboratory regional center of INRH in Nador, Morocco
³ South West University, Neofitrilski, Blagoevgrad, Bulgaria
⁴ University of Niš, Faculty of Science and Mathematics, Višegradska 33, Niš, Serbia
⁵ Coastal resource prospecting laboratory regional center of INRH in Casablanca.
⁶ National Laboratory for Pollution Studies and Monitoring (LNESP), Rabat, Morocco

^* Corresponding author: ouiamelmekki@gmail.com

Abstract

Heavy metal contamination in coastal ecosystems poses an environmental challenge, particularly in lagoons affected by agricultural, urban, and other anthropogenic discharges. This study examines the concentrations, spatial distribution, and ecological risks of heavy metalsincluding lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As), chromium (Cr), nickel (Ni), and zinc (Zn)in the sediments of Marchica Lagoon, Morocco. Sediment samples from ten stations were analyzed using an X-ray fluorescence (XRF) spectrometer. Pearson correlation and multivariate analysis were applied to identify contamination sources and assess pollution levels. The results indicate elevated Pb and Cd concentrations in urbanized areas, exceeding sediment quality guidelines. Cr and Ni display strong correlations, suggesting a common anthropogenic origin, while localized Hg and As contamination may be linked to natural mineralization and historical mining. Zn exhibits a diffuse distribution influenced by both natural and human activities. Urban runoff contributes to Pb, Cd, and Zn enrichment, whereas agricultural and geogenic processes affect Cr, Ni, and As distribution. These findings highlight the need for enhanced environmental monitoring and mitigation strategies to curb heavy metal accumulation. Periodic sediment assessments and targeted remediation are essential for preserving the lagoon’s ecological integrity and guiding sustainable coastal management policies.