In this survey, the concentration of some heavy metals (Ni, Fe, Cd, Al, Cr, Cu, Zn, Pb, and V) was investigated in the sediments and shells of the (Cerastodema lamarcki). The samples were collected from 10 sampling sites along the south west coast of the Caspian Sea in Guilan province region at February 2015. After initial sample preparation and acid digestion, the specimens were analyzed using ICP-OES device. The results showed that the bivalve shells have a proper potential for accumulation of Cu, Pb, Zn, Cr, and Cd, hence it can be used as a biomonitoring agent for these elements at the study areas. Statistical cluster analysis demonstrated that among the metals in sediment samples, iron and aluminum were categorized in an independent group. The results of Pearson correlation showed that there is a positive and significant correlation between Ni, V, Cr and Cd elements in the sediment and in the bivalve shells. The enrichment factor outcomes revealed that the sediments of the region are classified in a moderate level of enrichment for Cu, Ni and Cd. Comparison of the metal levels with some international standards indicated that the sediment quality was categorized at the medium level of pollution. Due to increasing growth in urbanization, industrialization and agricultural development at the region, the release of contaminants can lead to a significant potential environmental and human health threat. Hence, the monitoring of pollutant using hard shells of bivalve is a beneficial method that can provide useful information about the presence of the contaminants over the years.