全球智库信息集成服务系统

Twenty-nine and twenty-seven water samples were collected during October 7 to 10, 2005 and June 10 to 15, 2006, respectively in order to examine the surface water quality in central northern Mongolia related to the effect of mining. Major dissolved constituents in surface waters are mostly derived from rock weathering, which is accelerated by mining activity. The hydrogeochemical analysis indicates that the water-rock (soil) interaction with lesser effect of anthropogenic contamination controls the major ion chemistry of surface waters.

Very high turbidity caused by abundant suspended particles (mainly mineral grains) is one of the major concerns in this area, which is caused by strong erosion of river banks in meandering river systems, overgrazing by animals, and human activities such as agriculture, cultivation and mining. In the Zaamar gold mining area of Mongolia, the Tuul river water is highly turbid due to the disturbance of sediments and soils by placer gold mining activity and would adversely affect the riparian environmental system. The chemistry of surface water in the Khangal River is affected by the oxidation of sulfide minerals in relation to the mining of porphyry Cu(-Mo) ores. These rivers are merged to the Selenge River in downstream area and may eventually influence the environment of the Baikal watershed to cause a significant transboundary environmental problem. Although water quality problem in geochemical aspect due to mining is not significant at present, it should be continuously examined to minimize the transboundary movement of potential aquatic contaminants. It is, therefore, essential to develop a sustainable monitoring system to establish a water quality management plan for transboundary watershed environment in the Northern Mongolia along with the conservation of the Lake Baikal.