Date of this Version
Erforschung biologischer Ressourcen der Mongolei (2016) band 13: 263-270.
The biodiversity of the Selenga river basin and the receiving waters of the lake Baikal, are among the greatest in the world with over 1,700 known endemic species of plants and animals. Mining activities along the Selenga river and its tributaries pose a major threat of chemical contamination, potentially reducing habitat quality and suitability for aquatic species. Moreover, the Selenga river serves as a major water source for the lake Baikal. Little information exists on the chemical contaminant concentrations in the Selenga river basin. Thus, the objectives of our study were to evaluate the concentrations of metals in soil, sediment, and fish in the Selenga. The concentrations of the metals were then compared to thresholds for toxicity to aquatic organisms. We sampled at 16 locations in the Tuul, Selbe, Khangal, Boro, Orkhon, and Selenge rivers in Mongolia in 2010. Concentrations of copper, chromium, nickel, lead and mercury were above predicted thresholds for toxicity at selected locations; however, most metals were below threshold values at the majority of stations sampled. Copper concentrations were elevated in sediments from the river Khangal downstream of Erdenet, Mongolia. Boro river sediments, at a location downstream from historic gold mining operations contained elevated concentrations of arsenic, lead, nickel, and mercury. Fish from this location also contained mercury at concentrations hazardous to both the fish and predators, including humans. The river Selbe in Ulaanbaatar had sediments with elevated concentrations of lead and zinc. The concentrations of metals in soil, and sediments from the Selenga and its tributaries in Mongolia were largely below thresholds for toxicity to fish and aquatic invertebrates. A few exceptions existed in which the concentrations of selected metals would pose a threat to aquatic fauna and potentially biodiversity in those regions.
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