Aerosol samples were collected in the Shiyi Glacier, Qilian Mountains from July 24 to August 19, 2012 and analyzed for major water-soluble ionic species(F^-, Cl^-, NO_2^-, NO_3^-, SO_4^(2-), Na^+, NH_4^+, K^+, Mg^(2+) and Ca^(2+)) by ion chromatography. SO_4^(2-) and NH_4^+ were the most abundant components of all the anions and cations, with average concentrations of 94.72 and 54.26 neq/m^3, respectively, accounting for 34% and 20% of the total water-soluble ions analyzed. These mean ion concentrations were generally comparable with the background conditions in remote sites of the Qilian Mountains, but were much lower than those in certain cities in China. The particles were grouped into two dominant types according to their morphology and EDX signal: Si-rich particles and Fe-rich particles. Backward air mass trajectory analysis suggested that inland cities may contribute some anthropogenic pollution to this glacier, while the arid and semi-arid regions of central Asia were the primary sources of the mineral particles.
The eastern Xinjiang Basin is desperately short of water. Most rivers in the basin originate in the high eastern Tianshan, which has abundant precipitation and numerous alpine glaciers. Fieldwork conducted on three reference glaciers around Mt. Bogda in 1981 and 2009 suggests that they all strongly melt in summer, a process that has tended to accelerate in recent decades. Based on topographic maps from 1962 and 1972 and 2005/2006 satellite imagery, we investigated 203 glaciers near Mt. Bogda and 75 glaciers near Mt. Harlik. The results show that the surface area of the Mt. Bogda glaciers decreased by 21.6% (0.49% a?1) from 1962 to 2006. This was accompanied by a 181 m decrease in length and a 28% drop in ice volume. In the Mt. Harlik region, areal extent was reduced by 10.5% (0.32% a?1), length by 166 m, and volume by 14% between 1972 and 2005. South-facing glaciers lost more of their area than those that are north facing, yielding an areal loss of 25.3% and 16.9% for southern and northern slopes of Mt. Bogda, respectively, and 12.3% and 6.6% for the comparable slopes of Mt. Harlik. Glaciers smaller than 0.5 km2 in area experienced the strongest retreat, whereas glaciers larger than 2 km2 in area experienced gentle recession but may be the main contributors in the future to river runoff. Glacial ablation in eastern Xinjiang tends to be strong, and the water resources in this region are deteriorating. Also, a heavy reduction in the capacity of the local karez system, as well as a significant change in river runoff, can be related to glacial retreat. Combined, this will adversely affect the downstream city of Urumqi and the Turfan Basin.
Aerosol samples were collected at altitudes from 584 m a.s.l.to 3,804 m a.s.l.at seven sites of the eastern Tianshan.The occurrence,distribution,and possible sources of 47 trace metals—including alkali metals and alkali earth metals,transition metals,lanthanoids,and heavy metals—were investigated.It was found that four sampling sites(Shuinichang,1,691 m a.s.l.;Urumqi City,809 m a.s.l.;Fu Kang Station,584 m a.s.l.;and Bogeda Glacier No.4,3,613 m a.s.l.)were contaminated mainly by heavy metals.Other three high-altitude sites(Urumqi Glacier No.1,3,804 m a.s.l.;Wang Feng road-maintenance station,3,039 m a.s.l.;and Tianshan Glaciology Station,2,135 m a.s.l.)were not polluted.The aerosol particles were clustered into two dominant types:crust-originated particles and pollution-derived particles.Aerosols from UG1,WF,and TGS were characterized by crust-originated particles such as clay,plagioclase,dolomite,alkali feldspar,and biotite;while those from SNC,Urumqi,FK,and BG4 were characterized by high content of Cl-rich particles,S-rich particles,and soot.The backward-trajectories results indicated that air masses arriving at SNC,Urumqi,FK,and BG4 were identified as the more polluted source,when compared to the short-range air mass transport from the North to UGI and WF.Relatively lower altitude,as well as terrain blocking,might be another important reason for the gradient difference in pollution influence among these seven places in the Urumqi River Basin.
Daily samples of aerosol(n=27) were collected from September 21 st to October 4th, 2013 in Fukang(44.17oN, 88.45oE, 475 m a.s.l.), Xinjiang, Northwest China. The enrichment factors(EFc) of selected 49 elements showed that the aerosols had extremely high concentrations of heavy metals, probably indicating their anthropogenic origins. Morphology of individual aerosol particles was determined by scanning electron microscopy and energy-dispersive X-ray microanalysis. Based on morphology and elemental composition, the particles were clustered into three dominant types:(Ⅰ) crustal originated particles: Si/Al-rich particles(36%) and Si/Fe-rich particles(24%);(Ⅱ) mixed source particles; and(Ⅲ) pollution derived particles: Pb-rich particles(10%). The backward trajectories were calculated using the HYSPLIT model, and the results indicated the different anthropogenic sources for heavy metals in Fukang aerosols. Air mass from north was identified as the most polluted source when compared to south and west.
