Impacts of gold mining and land use alterations on the water quality of central Mongolian rivers

Abstract

Conservation of water quality is inherently tied to watershed management. Efforts to proect Lake Baikal have increasingly focused on the Selenge River, a major tributary, with more than half its watershed area in Mongolia. Placer gold mining in Mongolia has the potential to load total suspended sediment (TSS), and total phosphorus (TP) into Lake Baikal and destroy spawning areas for the endangered Taimen salmon (Hucho taimen taimen). This work describes water quality assessments performed from 2001 to 2003 on Mongolian tributaries to the Selenge River. Of 7 rivers sampled, rivers with proximal mining had the worst water quality. Elevated loading of TSS and TP was observed below mining regions on the Tuul River. Flooding could breach thin strips of land separating dredge pits from river channels, resulting in massive sediment loading. Extensive disturbance of the river terrace was apparent for many square kilometers. In the mountainous headwaters of the Yeroo River, tributary drainages undergoing mining had TP concentrations 8 to 15 times higher than the main stem. TSS was 7 to 12 times higher, and turbidity was 8 times higher. Alternative mining technologies exist that could minimize impact and improve the possibility for reclamation.

Fish conservation in the land of steppe and sky: Evolutionarily significant units of threatened salmonid species in Mongolia mirror major river basins

“…Mongolia's vast river basins include some of the least impacted freshwater ecosystems on the planet (Hofmann et al, 2015). However, across many regions, a multitude of anthropogenic pressures is currently threatening this pristine status, with increasing contamination and degradation of aquatic environments and their resident species (Stubblefield et al, 2005;Karthe et al, 2017). The damage to Mongolia's rivers, streams, and lakes has been a direct result of recent, rapid development, where high rates of urbanization and industrialization have led to growing discharge of poorly treated wastewater, increased industrial pollution and mining contamination, along with rising rates of overgrazing and deforestation in many river basins (Hartwig et al, 2016;Hofmann, Venohr, Behrendt, & Opitz, 2010;.…”

MODELING SPAWNING DATES OFHUCHO TAIMENIN MONGOLIA TO ESTABLISH FISHERY MANAGEMENT ZONES

“…The situation may provide a unique fisheries conservation opportunity: protecting taimen populations while allowing catch-and-release fly fishing may serve as a vehicle for the conservation of Mongolia's rivers. The urgency of such efforts is increasing: untapped mineral deposits combined with lack of environmental protections has made Mongolia an attractive location for mining development, and foreign investment in largescale mining (using environmentally devastating placer mining techniques) has already impacted some of Mongolia's rivers, and threatens to impact many more (Stubblefield et al 2005). By ''valuating'' a previously unvalued resource, a non-extractive taimen fishery can create incentives for protection of taimen and their habitat.…”

Analysis of Recent Nutrient Emission Pathways, Resulting Surface Water Quality and Ecological Impacts under Extreme Continental Climate: The Kharaa River Basin (Mongolia)

“…In addition to the "hot spots" of contaminants already identified in the Kharaa river basin HOFMANN and SCHARAW, 2009;HOFMANN and BEHRENDT, 2008) and for adjacent mining areas in general (STUBBLEFIELD et al, 2005), the following topics and countermeasures for reducing diffuse nutrient emissions are discussed: -The infiltration of untreated waste water from urban households (especially informal ger settlements) via soil passage to the groundwater represented a considerable proportion of the total emissions. The installation of septic tanks, decentralized small treatment plants (DCTP) adapted to the local conditions and re-use of treated waste water becomes an important measure.…”