天山乌鲁木齐河融雪和河川径流的水文化学过程

Hydrochemical Process of Snowmelt and Stream Water in rumqi River, Tianshan Mountains

研究结果表明， 含 Ｃａ Ｃ Ｏ３矿物的溶解作用在乌鲁木齐河源区居主导地位 尽管融雪径流的 “离子脉冲”作用可以释放峰值强度达 ３～４ 倍的 Ｓ Ｏ２４ 和 Ｎ Ｏ－３ 流， 并且引起了总控断面河川径流与之相像的“离子脉冲”现象，但河川径流仍然呈现弱碱性；河源区强烈的含 Ｓ矿物的氧化溶解作用，产生大量的 Ｈ＋ ，被含 Ｃａ Ｃ Ｏ３矿物的溶解作用所缓冲， 未引起河川径流的酸化乌鲁木齐河以冰川站为界， 以上地区的水文化学过程为矿物的侵蚀－ 溶解过程，以下则发生部分矿物的沉淀，如 Ｃａ Ｃ Ｏ３的沉淀 Ｃａ Ｃ Ｏ３ 的沉淀作用一定程度上又增强了河流的酸缓冲力

In China coal burning resultes in high concentrations of SO 2 4 , NO - 3 and H + in precipitation both within major industrial cities and in atmospheric deposition to high elevation areas where annual precipitation is dominated by snow fall In other areas of the world, significant and severe changes occur in terrestrial and aquatic ecosystems where levels of sulfur and nitrogen containing compounds are less than those currently existing in China As a part of ongoing effort to fully understand the susceptibility of seasonally snow covered alpine basins to deposition of atmospheric pollutants, this study aims at better understanding the process that controls the hydrochemistry of high elevation headwater basins during snowmelt period The research area is the upper part of the Urumqi River, with an area of 824 km 2 above the Hydrometric Station at Hero Bridge More intensive studies focused on the headwater basin with an area of 29 km 2 , including the Glacier No 1 basin, a glacierized headwater basin with an area of about 2 km 2 Daily samples of snowmelt and stream water were continuously collected for solute analysis from May 1 to June 30, 1996 at gauging station of the Glacier No 1 basin, several gauging stations in the headwater basin and several other sites down the stream within an interval of several kilometers It is found that pH is slightly less than 7 in snow and is 7 8 to 8 5 in stream water Ca 2+ and HCO 3 predominates in cations and anions in the stream water, accounting for approximately 73% and 77% of total cationic and anionic charges, respectively It is suggested that dissolution of CaCO 3 -containing minerals is the major geochemical process in stream water at the headwaters of the Urumqi River catchment Under the Tianshan Glaciological Station near the Hero Bridge, however, ionic concentrations of some species were saturated Mineral deposits can be seen in the stream water such as calcite, dolomite and gypsum Althouth the ionic pulse occurs and concentration of SO 2- 4 and NO - 3 increases with a peak of 3 to 4 times of the average concentrations, the stream water of headwaters is not acidified during the initial snow melting period Oxidation and dissolution of S containing minerals such as FeS 2 produces a large amount of H + H + is then consumed by dissolution of CaCO 3