عنوان مقاله [English]
In this study, to investigate the concentration of heavy metals in the river mouth of important rivers in the southern Caspian Sea, 50 surface sediment samples (1 core) collected. analysis of grain size, organic matter, ICP were performed on the samples. Based on the mean concentrations, the highest mean concentrations of iron, aluminum, chromium, cobalt, lead and vanadium were observed in Ramsar (Safarud), arsenic in Gorganrud and zinc in Gharasoo rivers, respectively, Also, the lowest concentration of elements in the core of Gorgan Bay (K5) and a depth of 85 cm with an approximate age of 1400 years was obtained, which was used as a baseline reference. Based on different pollution indicators, the degree of pollution (Cd) in 3 rivers of Babolrood, Cheshmeh Kileh and Sardabroud are in the range of moderate pollution and in the rivers of Gorganrud, Qarah Su, Tajan, Ramsar and Sefidrood are in the range of significant pollution. based on the modified degree of pollution index, all rivers are classified in the range of low to medium degree of pollution, and each stream (PLI) in most stations showed in the range of more than 1 (slightly polluted to polluted), but ecological risk (RI) were still in the low risk range. Also, the enrichment factor (EF) in the sediments of the estuarine sections showed that the above rivers are probably enriched by various factors such as geology, climatic conditions and human factors and have moderate to severe pollution.