Spatial Distribution Characteristics And Environmental Significance Of Trace Elements In Northern Xinjiang

The trace elements carried in the snow can be a good assessment of the pollution status of the local atmosphere This paper is based on 82 groups of snow samples collected in Tianshan North slope,Yili Valley,Tacheng area in January 2018 and Altay region in January 2019.After a rigorous acidification process,the concentration of 13 trace elements,including Al、Fe、Mn、Be、Cr、Co、Ni、Cu、Zn、As、Cd、Ba、Pb,were determined by an inductively coupled plasma mass spectrometer（ICP-MS）.And the spatial distribution of trace elements in the snow in northern Xinjiang was analyzed.Besides,compared with other regions,the concentration level of trace elements in snow cover in northern Xinjiang was understood and the contamination degree and potential sources of trace elements in snow in northern Xinjiang were explored using element enrichment factor and HYSPLIT posterior trajectory model.The results show that:（1）The content of various trace elements in the snow in northern Xinjiang varies greatly.In2018,between Cd(0.06 ng·g^-1)and Al(1798.92 ng·g^-1).In 2019,between Cd(0.05 ng·g^-1)and Al(1859.76 ng·g^-1).The total mean concentration is slightly higher in 2019(288.14ng·g^-1)than in 2018(281.84 ng·g^-1),reflecting that the winter air trace element pollution in2018 and 2019 is generally at the same level.（2）In terms of spatial distribution,the overall trend of northern Xinjiang in 2018 and 2019is that the content of most trace elements in the northern slope of Tianshan Mountain and Tacheng area was 1～3 times higher than that of Yili Valley and Altay area.This may be related to the fact that the unique terrain of the northern slope of Tianshan Mountain is easy to form inversion layer in winter,leading to the easy diffusion of air pollutants,and the geographical location of Tacheng area is vulnerable to the influence of pollutants in Central Asia.（3）Compared with the content of trace elements in the snow ice in other regions,it is found that the corresponding trace elements in northern Xinjiang are slightly lower than that in northeast China,significantly higher than those in the neighboring Qinghai-Tibet Plateau,and generally consistent with the No.1 glacier in Urumqi Heyuan,revealing the characteristics of high trace elements in the snow in northern Xinjiang.（4）In terms of enrichment,Ni,Cu,Zn,As,Cd（EF>5）are significantly enriched in the snow in northern Xinjiang,highly enriched（EF>20）,serious pollution,and significant increase with the decrease of Al content,dominated by human activities such as petroleum smelting,non-ferrous metal mining and coal-fired power generation.Fe,F e,Be,Ba,Cr,Co（EF<5）are slightly enriched,mainly contributed by natural sources such as dust.（5）Trace elements in the snow in northern Xinjiang are affected by external input from Central Asia such as Kazakhstan,especially in Tacheng area,and the West Siberian Plain and Mongolian Plateau are also potential source areas.Influenced by topographic factors in the Ili River Valley,local human activity emissions and short-range transportation in the surrounding areas have a greater impact on it.