This paper focuses on heavy metal distribution patterns in sediments of central Guilan (CG) and east Mazandaran
(EM) in the south Caspian Sea coasts, north of Iran. Sediment sub-samples were retrieved from core and surficial
samples in different environments of marine and coastal lagoons as well as coastal outcrops. Inductively Coupled
Plasma Mass Spectrometry and Atomic Emission Spectrometry (ICP-MS and ICP-AES) analysis were used to
determine the metal chemistry. Concentration of the selected heavy metals exhibited variations through sediment
samples which are partially related to grain size and organic matter content. Geoaccumulation index and statistical
procedures have been implemented for analyzing the absolute metal values. Result of the geoaccumulation index
demonstrated that the metal distribution reflects the influence of geological background of the watershed area.
Some elements including Pb, Ni, Cu, Sr and Ba showed elevated concentration in the CG that could be attributed
to development of industrial activities. A comparison of the metal concentration in the marine sediments and the
Late Holocene outcrops revealed that the level of the metals concentration at the sea generally corresponds to
natural background. The northern part of Iranian multi-lithological catchments basin is the main source for the
sediments that drained by the rivers to the South Caspian Sea basin
