Editing Selenga (section)

== Water quality ==
Before the turn of the millennium, the Selenga River and Lake Baikal had rich aquatic ecosystems nearly untouched by human influence. Since the collapse of the Soviet Union in the 1990s, the basin, which contains vast plains, has been affected by agricultural, climatic and economic factors. This includes changes like forest losses, urbanization and a growth in farming and mining activities.<ref name=":9" />

Factors that affect the water quality of the Selenga River can be classified as either anthropogenic or natural factors. Anthropogenic factors include mining activities, agriculture, breeding, dumping of wastewater into water bodies and water use. Natural factors include erosion processes and weathering.<ref name=":3">{{Cite book|last1=Chu|first1=JangMin|title=Integrated water management model on the Selenge River basin.|last2=Lee|first2=ChangHee|last3=Janchibdorj|first3=Lunten|last4=Oktyabrevich Gomboev|first4=Bair|last5=Park|first5=SangYoung|last6=Mun|first6=HyunJoo|publisher=Korea Environment Institute|year=2010|isbn=978-89-8464-449-6}}</ref> The escalation of anthropogenic factors can be correlated with pollution by "potentially toxic elements, including metals and persistent organic pollutants."<ref name=":9" /> Mongolia has had rapid growth in GDP since 1999, fueled by agriculture, mining and light industry. These activities, particularly mining, have threatened the surface water quality of the Selenga River and adjacent groundwater.<ref name=":3" />

A study published in volume 12 of the journal ''Water'', found that based on the Mongolian National Standard, "the main pollutants of the Selenga River are [[Zinc|Zn]] ... [[Arsenic|As]] ... and [[Lead|Pb]] ..." They also found that metal content in the river water was tens or hundreds of times higher in sites closer to urban and mining areas.<ref name=":9" /> Based on data observing toxicological and bioaccumulation effects on aquatic biota, the contamination has been shown to have an ecological impact.<ref>{{Cite book|last1=Batbayar|first1=Gunsmaa|title=Chemical Water Quality in Selenge River Basin in Mongolia: Spatial-temporal Patterns and Land Use Influence|last2=Kappas|first2=Martin|last3=Karthe|first3=Daniel|last4=Sauer|first4=Daniela|last5=Ruppert|first5=Hans|last6=Pfeiffer|first6=Martin|last7=Schlund|first7=Michael|publisher=[[Georg-August-Universität Göttingen]]|year=2018}}</ref>