Environmental impacts of Aghdarband coal mine: pollution by heavy metals

Aghdarband coal mine, located in NE of Iran, with annual coal and waste production capacity of about twenty million and six thousand tons, respectively, causes the increase of the concentration of some heavy metals in the soil and surrounded sediments. This paper deals with geochemical distribution and environmental effects of the heavy metals on the sediments around the mine, using geochemical data and statistical analysis. Investigation of the correlations of soil chemical parameters based on Pearson correlation coefficients, cluster analysis and principal component analysis suggested that sulfur, arsenic, molybdenum and copper were distributed in the region under the effect of anthropogenic origin (coal washing plant). Also, magnesium, nickel, cadmium and chromium were caused by the lithogenic origin effect (ultramafic rocks) in soil and sediment of the region. These studies also revealed that the concentration and geochemical distribution of aluminum, manganese, antimony, cobalt, iron, zinc and lead was controlled by the acidic rocks (rhyolites, metamorphosed acidic tuffs) and the metamorphosed politic sediments (slate and phyllite) and the calcium element by the carbonate rocks. Calculation of the enrichment and geo-accumulation factors also shows that the soil of the region is polluted by the elements such as sulfur, arsenic, copper and lead. Zoning maps of elements concentration also showed that these elements have the highest concentration at the place of coal washing and coking plan, as the concentration was gradually decreased by moving away from these locations.