Study of heavy metals (Cd, Cr, Zn, and Pb) in water and sediment from coastal waters of Golestan Province, Iran

The presence of heavy metals more than standard limits in the aquatic habitats can create significant environmental issues and complications for aquatic organisms. In this study, the concentration of four heavy metals (Cd, Cr, Zn, and Pb) in water and sediments of four areas, including the west and east coasts of Golestan Province, Gomishan Lagoon and Gorgan Bay at 11 sites were determined. The prepared samples were analyzed by Atomic Absorption Spectrophotometer (AAS) technique. The results showed that the highest concentration of Lead (214.83 ppb) was belonged to Gomishan Lagoon and the lowest Chromium level (28.83 ppb) was observed in specimens sampled from the east coast in the winter. Furthermore, the highest concentration of Zinc (3000.7 ppb) was found in sediment specimens collected from Gomishan Lagoon in the summer, as well as the lowest concentration of Cadmium (121.7 ppb) was reported in Gorgan Bay in the summer. No significant difference was observed between the concentrations of heavy metals in water and sediment (P>0.05). In addition, the highest level of heavy metal measured in water in all areas was belonged to Lead and in sediments was belonged to Zinc as well. Overall, the results of the present study in compared to World Health Organization (WHO) indicated that the concentrations of the studied heavy metals were lower than the stated standard level for it.