Assessment of Heavy Metal Contamination and Pollution Indices in Avicennia marina of Nabq Mangrove Forest, the Red Sea, Egypt

Mangrove forests are vital for the filtration of land-derived wastewater in industrialized tropical and sub-tropical coastal regions, contributing to the preservation of marine ecosystems. However, intertidal communities currently face significant challenges. One major concern is the potential threat posed by heavy metal contamination resulting from human activities associated with rapid urbanization and industrialization. Extensive research has been conducted to understand the biotic responses of mangrove plants to heavy metal exposure. Contaminants have significant implications for estuary management and coastal ecosystem preservation. This study focused on assessing the heavy metal in the tissue of the mangrove tree  Avicennia marina collected from the Nabq protectorate area, the Red Sea. The enrichment factor (EF) values of seawater in the study area provide insights into the contamination levels. Notably, all sampled locations in the investigated region displayed EF values below 1, suggesting minimal contamination by these metals. The analysis of the Metal Pollution Index (MPI) of water in the Nabq area revealed that the examined sites within the Nabq protectorate experienced a minor degree of metal pollution. The sites examined are classified in class III. This classification is based on the MPI values falling within the range of 1- 2 levels for all sites within the protectorate. Metal concentrations in leaves, roots, stems, and surrounding seawater were investigated in twelve locations within the studied area. The analysis revealed that the concentrations of metals were ordered from high to low concentrations as follows: roots> leaves> stem. Manganese had the highest concentration of bioconcentration factor among the elements examined in the roots, leaves, and stem of Avicennia marina.