祁连山冰川中痕量元素的空间分布及其来源分析

Analysis of the sources and spatial distribution of trace elements in Qilian Mountains glaciers

痕量元素在山地冰川中的时空格局可以作为评价人类活动对大气环境影响的良好指标。为了研究祁连山雪冰中痕量元素的空间分布及其主要来源,2020年9月在祁连山的7条冰川,包括阿尔金山冰川、扎子沟冰川、老虎沟冰川、七一冰川、四号冰川、八一冰川和宁缠河3号冰川中采集表层雪样进行酸化处理,使用电感耦合等离子体质谱仪(Inductively Coupled Plasma-Mass Spectrometry,ICP-MS)测定了大量元素Al、Fe与痕量元素As、Ba、Co、Cr、Cu、Li、Mn、Mo、Pb、Sr、Tl、Zn、Cd的浓度,并选用Jonckheere-Terpstra非参数检验来对比痕量元素平均浓度,数据结果表明祁连山西部扎子沟冰川和老虎沟冰川的痕量元素浓度较高,祁连山东部宁缠河3号冰川痕量元素浓度较低,痕量元素浓度总体空间分布趋势为西段>中段>东段。痕量元素总浓度的富集因子(Enrichment Factors,EF)表明,Co、Cr、Cu、Tl、Fe、Li、Mn、Mo、Sr元素主要受自然粉尘输入影响(EF<10),Pb、Cd、Zn元素受人为源影响较大(EF>10)。然后对痕量元素浓度数据进行主成分分析(Principal Component Analysis,PCA),发现7条冰川的第1主成分中总浓度上有较高正载荷的元素主要来源于自然粉尘源,特别是新疆地区的粉尘,第2主成分则代表不同程度的人为源影响。最后结合后向轨迹的聚类分析表明,研究区主要受西风环流控制,痕量元素自然输入源主要来自新疆中部和北部的沙漠和盆地等,而人为源则包括河西走廊部分城市人类活动、交通运输排放、矿物开采和金属冶炼等。本研究为祁连山脉各分段地区冰川人类活动对环境的影响作用提供了数据支持,为祁连山地区的生态文明建设和社会经济的可持续发展提供了重要的科技支撑。

The content variation of trace elements in mountain glaciers can be used as a good index to evaluate the impact of human activities on atmospheric environment.In order to illuminate the spatial distribution and the main sources of trace elements in snow ice of Qilian Mountains,on September 15,2020,surface snow samples were collected from seven glaciers in the Qilian Mountains,including Aerjin Glacier,Zhazigou Glacier,Laohugou Glacier,Qiyi Glacier,Glacier No.4,Bayi Glacier,and Ningchanhe Glacier No.3.The samples were acidified to analyze the spatial distribution of trace elements and their primary sources.Using ICP-MS,the concentrations of 15 metallic elements(Al,Fe,As,Ba,Co,Cr,Cu,Li,Mn,Mo,Pb,Sr,Tl,Zn,and Cd)were measured,and the average trace element concentrations were compared using the Jonckheere-Terpstra nonparametric test.Higher trace element concentrations were found in Zhazigou Glacier and Laohugou Glacier in the western part of the Qilian Mountains,while lower concentrations were found in Ningchanhe Glacier No.3 in the eastern part.The overall spatial distribution trend of trace element concentrations was west>middle>east.Enrichment factors(EF)for total trace element concentrations were calculated,showing that elements Co,Cr,Cu,Tl,Fe,Li,Mn,Mo,and Sr were mostly influenced by natural dust input(EF<10),whereas elements Pb,Cd,and Zn were more influenced by anthropogenic sources(EF>10),such as industrial emissions,coal mining,and fossil fuel combustion.The trace element concentration data were subjected to Principal Component Analysis(PCA),revealing that elements with high positive loadings on the total concentration in the first principal component mainly originated from natural dust sources,especially in the Xinjiang region.The second principal component represented varying degrees of anthropogenic source effects.Additionally,clustering analysis combined with a backward trajectory demonstrated that the study area is primarily influenced by the westerly circulation,and the natural input sources of trace elements mainly come from deserts and basins in central and northern Xinjiang.Anthropogenic sources include human activities in some cities along the Hexi Corridor,transportation emissions,mineral extraction,and metal smelting.This study provides data support for the impact of glacial human activities on the environment in various segments of the Qilian Mountains.These findings provide important scientific and technological support for the construction of ecological civilization and sustainable social and economic development in the Qilian Mountains.