The environmental impact of mining, first of all, is contamination of surface water, groundwater, soil by chemicals from mining processes, and erosion, formation of sinkholes, loss of biodiversity, etc. The mine dumps, tailings dams and resultant siltation of drainages into creeks and rivers can significantly impact on surrounding areas. As a result, the rivers of mining closely area are extremely polluted by toxic heavy metals, such as Cd, Pb, As, Ni, Fe, and Mn and so on. For this propose the pollution level by heavy metals of Debed River and its tributary, as the main river of Armenia in Lori Region, was assessed during 2010-2013. It was shown that the heavy metals content highly increased to down by stream flow in Debed River due to Axtala tributary. The Akhtala River flows through the mine dumps and tailings dams of “Akhtala Mountain-Enrich Combinat” CJSC, which caused the intake of huge amount of heavy metals into the river. As a result the concentrations of iron, manganese, copper, zinc, lead were 10-100 times increased in the Debed River after the intake of its Akhtala tributary. Due to mining impacts with toxic metals on rivers in the Lori Region, the flora and fauna in the Akhtala River were destroyed and disappeared at all, and in the Debed River are at risk.