Assessment of heavy metals concentrations and pollution in sediments of Almejogh Ophiolite Region (North-East of Iran)

Heavy metals can be present at low concentrations in the soil and contaminate it. Since the study area is ophiolite in terms of lithology, it can increase the concentration of heavy metals in soil and water resources. In this study, the concentration of heavy metals has been investigated and the pollution in sediments of Almejogh region (Fariman ophiolite) is evaluation. To study the concentration of heavy metals and sediment pollution in the study area, 9 samples of sediment were taken from depth of 30 to 20 cm. The samples were transferred the environmental laboratories of Islamic Azad University of Mashhad and the amounts of pH and EC in soil were measured. 10 grams of soil (material passing through a 200-mesh sieve) was transferred to the ACME Laboratories of Canada in order to be analyzed for determining the amount of heavy metals by the induction plasma-mass spectrometry (ICP-OES) method. Study of the correlation of heavy metals by Pearson coefficient, cluster analysis and principal components analysis showed that there are two different origins for geochemical distribution of heavy metals in sediment of the region. Ophiolite set of distribution of Cobalt, Nickel, Chromium and Pyroclastic and volcanic set as well as distribution of Iron elements, Molybdenum, Vanadium, Copper, Arsenic, Lead, Potassium and Cadmium were controlled. The pH of the soil in the study area fell within the pretty alkaline limit based on the classification of American soil science society. Evaluation of enrichment factor showed that Nickel has a very high enrichment and Arsenic and Chromium were in a high enrichment region. The above enrichment is indicative of anthropogenic origin. The pollution coefficient also showed that Nickel has the highest pollution in the region. The index of accumulation (of earth) also indicates t contamination of the sediment with Nickel in the region.