Water Chemistry Variations of Lake and Inflowing Rivers Between Pre- and Post-monsoon Season in Nam Co,Tibet
Received date: 2012-05-11
Request revised date: 2012-07-10
Online published: 2013-01-20
Copyright
In mid-May (pre-monsoon season) and late October (post-monsoon season), water samples were taken from 2 sites in Nam Co Lake and 16 rivers around the lake for dynamic changes study of water chemical composition in different seasons. Water chemistry analysis and comparative studies have been conducted to illustrate the dynamic changes of ions concentrations between the two seasons. The results indicated that all ions showed higher concentrations in post-monsoon than that in pre-monsoon season for lake water.Among them, Mg2+ increased by 46.84% and 46.95% on average in two sites, while Ca2+ increased by 67.02% and 75.11% on average, respectively.Na+ and K+ showed relatively less increase in concentration. As for anions, HCO3- showed the largest increase of 27.61% and 25.02% in two sites, respectively. Meanwhile, most ions in river water also showed the similar trends, Mg2+ and Ca2+ increased by 40.55% and 33.20% on average in all rivers. HCO3- and SO42- increased 36.81% and 28.48%. However, F-, Cl- and NO3- showed opposite patterns, i.e., the concentrations were lower in post-monsoon season. Cl- was the most remarkable decreasing ion, averagely decreased 28.43% in all rivers. It is indicated that the ion concentrations dynamic changes of Nam Co Lake and river water were mainly influenced by weathering in the drainage area. Weathering production such as Mg2+, Ca2+ and HCO3- were the main source of increased ions, resulting from the weathering of carbonate in the catchment. On the other hand, lake evaporation has also slightly contributed to ion concentrations increase of lake water. The river Cl- decrease in post-monsoon season was mainly influenced by individual river flux, more changes in river flux between two seasons led more decrease of Cl- concentration and the ultimate controlling factors should be water supply from precipitation and glacier melting water within the catchment.
WANG Jun-bo , JU Jian-ting , ZHU Li-ping . Water Chemistry Variations of Lake and Inflowing Rivers Between Pre- and Post-monsoon Season in Nam Co,Tibet[J]. SCIENTIA GEOGRAPHICA SINICA, 2013 , 33(1) : 90 -96 . DOI: 10.13249/j.cnki.sgs.2013.01.90
Fig.1 Samping sites of Nam Co water and the 16 rivers图1 纳木错湖水和周边16条河流采样点 |
Table 1 Statistics of major ions concentrations of T1 station and their change (mg/L)表1 T1站点各离子含量的统计量及变化(mg/L) |
采样时间 | 统计量 | Na+ | K+ | Mg2+ | Ca2+ | F- | Cl- | SO42- | HCO3- |
---|---|---|---|---|---|---|---|---|---|
5月14日 | 最小值 | 300.30 | 35.46 | 85.57 | 9.19 | 5.28 | 57.27 | 191.81 | 907.40 |
平均值 | 315.95 | 36.83 | 89.55 | 9.08 | 5.53 | 59.63 | 205.36 | 994.63 | |
最大值 | 323.69 | 37.62 | 92.63 | 10.98 | 5.81 | 61.72 | 225.19 | 1051.96 | |
10月27日 | 最小值 | 327.72 | 36.47 | 126.09 | 15.93 | 5.54 | 60.03 | 196.29 | 1239.61 |
平均值 | 335.84 | 37.84 | 131.50 | 16.69 | 5.87 | 63.65 | 207.47 | 1269.23 | |
最大值 | 340.37 | 38.82 | 136.08 | 18.12 | 6.29 | 68.37 | 218.30 | 1306.00 | |
增加(%) | 6.30 | 2.73 | 46.84 | 67.02 | 6.16 | 6.74 | 1.03 | 27.61 |
Table 2 Statistics of major ions concentrations of T2 station and their change (mg/L)表2 T2站点各离子含量的统计量及变化(mg/L) |
采样时间 | 统计量 | Na+ | K+ | Mg2+ | Ca2+ | F- | Cl- | SO42- | HCO3- |
---|---|---|---|---|---|---|---|---|---|
5月16日 | 最小值 | 302.29 | 35.00 | 77.88 | 8.60 | 5.51 | 58.34 | 195.15 | 898.83 |
平均值 | 317.80 | 36.73 | 89.24 | 9.74 | 5.69 | 59.13 | 200.56 | 1003.50 | |
最大值 | 329.60 | 37.99 | 94.44 | 12.24 | 6.01 | 60.76 | 207.67 | 1060.36 | |
10月29日 | 最小值 | 321.49 | 36.44 | 114.59 | 12.96 | 5.79 | 65.00 | 206.68 | 1193.77 |
平均值 | 338.75 | 38.80 | 131.44 | 17.05 | 6.08 | 38.18 | 219.02 | 1254.62 | |
最大值 | 366.25 | 41.54 | 136.74 | 18.77 | 6.35 | 72.22 | 237.05 | 1297.97 | |
增加(%) | 6.59 | 5.62 | 46.95 | 75.11 | 6.77 | 15.30 | 9.20 | 25.02 |
Fig.2 Vertical variation of major anions concentrations of T2 station图2 T2站点主要阳离子含量变化 |
Fig.3 Comparison of major anions concentrations from the 16 rivers around Nam Co图3 纳木错周边16条河流主要阳离子含量对比 |
Table 3 Statistics of major ions concentrations and their changing rate from the 16 rivers around Nam Co (mg/L)表3 纳木错周围16条河流主要离子含量的统计量及变化(mg/L) |
采样时间 | 统计量 | Na+ | K+ | Mg2+ | Ca2+ | F- | Cl- | NO3- | SO42- | HCO3- |
---|---|---|---|---|---|---|---|---|---|---|
5月18日 | 最小值 | 1.40 | 0.53 | 0.68 | 6.82 | 0.16 | 0.49 | 1.16 | 5.91 | 21.84 |
平均值 | 6.57 | 1.31 | 5.50 | 23.68 | 0.40 | 1.55 | 1.87 | 27.67 | 78.19 | |
最大值 | 18.22 | 4.69 | 17.11 | 54.38 | 0.65 | 5.72 | 3.02 | 37.35 | 240.42 | |
10月31日 | 最小值 | 1.77 | 0.36 | 0.90 | 8.83 | 0.08 | 0.34 | 0.30 | 6.63 | 28.89 |
平均值 | 7.49 | 1.40 | 7.72 | 31.54 | 0.38 | 1.11 | 1.62 | 35.54 | 106.98 | |
最大值 | 21.44 | 5.64 | 25.93 | 62.27 | 0.69 | 4.46 | 2.79 | 72.75 | 322.17 | |
增加% | 14.03 | 6.89 | 40.55 | 33.20 | -6.62 | -28.43 | -13.49 | 28.48 | 36.81 |
Table 4 Statistics of variation of major ions concentrations from the 16 rivers around Nam Co(%) (data in late October compared to that of middle May)表4 纳木错周边16条河流主要离子含量变化(10月下旬相比于5月中旬)的统计量(%) |
统计量 | Na+ | K+ | Mg2+ | Ca2+ | F- | Cl- | NO3- | SO42- | HCO3- |
---|---|---|---|---|---|---|---|---|---|
最小值 | -12.13 | -30.90 | 10.57 | 9.05 | -47.94 | -59.09 | -87.85 | -0.86 | 6.07 |
平均值 | 22.30 | 2.75 | 42.56 | 35.60 | -10.30 | -33.30 | -7.77 | 33.62 | 41.25 |
最大值 | 80.70 | 30.07 | 91.95 | 70.52 | 20.40 | -9.33 | 57.04 | 86.35 | 82.72 |
Fig.4 The concentrations and change of Cl- from the 16 rivers around Nam Co图4 纳木错周边16条河流Cl-含量及变化: |
The authors have declared that no competing interests exist.
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[4] |
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[5] |
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[7] |
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[8] |
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[9] |
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[10] |
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[11] |
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[12] |
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[13] |
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[14] |
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[15] |
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[16] |
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[17] |
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[18] |
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[20] |
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[21] |
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[23] |
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[25] |
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[26] |
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