Chemical Characteristics of Snow-Firn Pack in Altai Mountains and Its Environmental Significance

In order to study the chemical characteristics of snow-firn pack in Altai Mountains and its environmental significance, a 1.5-m deep snow-firn pack was dug in the accumulation zone (3 300 m a.s.l.) of the Kanas Glacier in August 2009. A total of 15 samples were analyzed for major ions. Results show that the concentrations of major ions in the snow-firn pack are NH4+>SO42->Ca2+>NO3-> Na+>Cl->K+>Mg2+. NH4+ is the dominant cation with a medium value of 4.7 ueq·L-1, accounting for 39.8% of the total cations, and SO42- is the dominant anion, with a medium value of 4.0 ueq·L-1, which accounts for 33.9% of the total cations. Compared with Belukha Glacier (Altai), Urumqi Glacier No. 1, and the Inilchek Glacier (Tienshan), there is a lower ion concentrations in the Kanas snow-firn pack. Potential sources of these chemical species are explored using correlation and empirical orthogonal function (EOF) analyses. The analyses indicate that major ion concentrations (except NH4+) originate from crustal dust. Backward trajectory analysis was applied to get the origin of the air mass to Kanas Glacier. The results suggest that air pollutants emitted by forest fires in Siberia could be transported and influence the NH4+, NO3-, and SO42- concentrations on the Kanas Glacier.