Investigation of accumulation of heavy metals in sediment and Avicennia marina (Forssk.) Vierh. plants of Khorkhoran protected area

Increasing industrial activity, followed by the entry of heavy metal pollutants into the aquatic ecosystems, are one of the biggest environmental challenges. Plants are good indicator of metals concentration in water and sediment of aquatic ecosystems. The aim of this study was to investigate the concentration of heavy metals in sediments, roots, stems and leaves of mangrove trees in Khorkhoran protected area as one of the most important mangrove habitats in the Persian Gulf. For this purpose, 9 samples of sediment, leaves, roots and stems were collected from this area and analyzed by ICP-OES to determine the concentration of heavy metals. Shapiro, Kruskal-Wallis, Tukey and bioaccumulation index and transfer coefficient were used for statistical analysis. The results showed that the highest concentrations of heavy metals in sediment samples were specific to nickel, zinc, copper and lead, respectively, and in the plant the highest concentrations were related to zinc, nickel, copper and lead. In general, the process of accumulation of metals in sediment and plant tissues indicates an increase in the concentration of metals in plant tissue with an increase in sediment. Bioaccumulation index showed that the highest and lowest concentrations of heavy metals were in roots and leaves, respectively, and mangrove root is a suitable indicator for measuring mangrove contaminants. The transfer coefficient of nickel metal in the stem and copper metal in the leaf showed the ability of these organs for phytoremediation of these two metals. The results showed mangroves are repelling species for other metals.