| Boron isotopic geochemistry of karst groundwater in Guiyang City, China |
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| 作者姓名： | Wei ZHANG Congqiang LIU Zhiqi ZHAO |
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| 作者单位： | [1]State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China [2]Graduate School of the Chinese Academy of Science, Beijing 100039, China |
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| 摘 要： | Boron has two stable isotopes （^10B and ^11B） with relative abundances of about 20% and 80%, respectively. Boron isotopic ratios in natural materials show a huge range of variations, from -70‰ to ＋60‰, when expressed with the classical δ^11B notation. Most of these isotopic variations occur at the surface of the Earth. Hence, boron isotopic composition can be used as a sensitive tracer in geochemical study, for instance, to identify the different sources of contamination and factors controlling the salinity of groundwater. During the last decade, boron isotopes have been used to discriminate between the influences of seawater intrusion and anthropogenic discharge. But few of those researches can precisely identify the different sources of contamination. We measured the boron concentrations and boron isotopic ratios of groundwater samples collected in Guiyang City, as well as the major ions. The results indicate that the major ion composition of the groundwater in the investigated area is mainly controlled by the interactions between water and the dominant rock i.e. carbonates. All the water compositions are characterized by high concentrations of Ca^2＋, Mg^2＋, HCO3^-, SO4^2-, and NO3^-, which are the dominant contaminants. Both dissolved boron concentrations and isotopic ratios show large variations among the ground waters, from 2 μg/L to 90 μg/L and from -6‰ to ＋26‰, respectively. The boron concentrations and isotopic ratios indicate that the river across the studied city has been seriously contaminated by urban discharge. Boron concentrations of fiver water samples varied from 20 μg/L to 140 μg/L, with an average δ^11B value of ＋2.0‰. Using boron isotopic compositions and different geochemical indices allowed us to clearly identify and distinguish the two major sources of contamination, agricultural activity and urban wastewater. Both of the two sources are characterized by high boron concentrations but their boron isotopic compositions significantly differ.
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| 关 键 词： | 硼 同位素 地下水 水体污染 贵阳市 地球化学 |
Boron isotopic geochemistry of karst groundwater in Guiyang City, China |
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| Wei ZHANG Congqiang LIU Zhiqi ZHAO.Boron isotopic geochemistry of karst groundwater in Guiyang City, China[J].Chinese Journal of Geochemistry,2006,25(B08):172-172. |
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| Abstract: | |
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| Keywords: | boron isotope ground water pollution Guiyang City China |
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