Heavy metals (Cd, Cu, Zn, Pb, Ni, Cr) assessment in water and brown algae (Polycladia indica) along the northern coast of Makoran Sea

Aquatic ecosystems, particularly marine and coastal areas, are exposed to various environmental pollutions (e.g., organic and heavy metals pollution), which are caused by natural phenomena as well as human activities in aquatic environments. The aim of this study was to evaluate the concentration of heavy metals in water and brown algae Polycladia indica as a bioindicator along the northern coast of the Makoran Sea and compare their concentrations with global standards and previous studies. Material and methods: For this purpose, concentrations of heavy metals (i.e., cadmium (Cd), copper (Cu), zink (Zn), lead (Pb), nickel (Ni), chromium (Cr)) were assessed in P. indica and water samples in ten stations along the northern shores of Makoran Sea in the autumn of 2017. Samples were transferred to the laboratory and heavy metals were measured by atomic absorption spectroscopy (AAS). In brown algae samples, Zn had the highest concentration within the whole area followed by Cr, Ni, Cu, Pb, and Cd, respectively. For water samples, the concentration of Cr was the highest followed by Zi, Ni, Cu, Pb, and Cd. One way-ANOVA test showed significant differences in the concentration of metals between sampling stations (p<0.05). The concentration of heavy metals in water samples was lower than the global standards. Strong correlations were found between the examined heavy metals, indicating the lack of diversification of pollution sources in the northern coasts of the Makoran Sea and the uniformity of the geochemical composition of the coastal geology units of the sampling regions. The results of this study indicate the high affinity of P. indica towards the absorption of heavy metals, and therefore, this species can be considered as a bioindicator of heavy metals contamination in the northern shores of the Makoran Sea.