气候变化领域集成服务门户(CCPortal): Characterization of groundwater in the Ejina Basin, northwest China: hydrochemical and environmental isotopes approaches

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DOI	10.3724/SP.J.1226.2010.00477
	Characterization of groundwater in the Ejina Basin, northwest China: hydrochemical and environmental isotopes approaches
	Su, YongHong; Feng, Qi; Chang, ZongQiang; Si, JianHua; Cao, ShengKui; Xi, HaiYang; Guo, Rui
发表日期	2010
ISSN	1674-3822
起始页码	477
结束页码	+
卷号	2 期号:6
英文摘要	To characterize the groundwater in the Ejina Basin, surface and groundwater samples were collected in May and October of 2002. On-site analyses included temperature, electrical conductance (EC), total alkalinity (as HCO3-) by titration, and pH. Chemical analyses were undertaken at the Geochemistry Laboratory of the Cold and Arid Region Environmental and Engineering Institute, Chinese Academy of Sciences, Lanzhou, China. The pH of the groundwater ranged from 7.18 to 8.90 with an average value of 7.72, indicating an alkaline nature. The total dissolved solids (TDS) of the groundwater ranged from 567.5 to 5,954.4 mg/L with an average of 1,543.1 mg/L and a standard deviation of 1,471.8 mg/L. According to the groundwater salinity classification of Robinove et al. (1958), 47.4 percent of the samples were brackish and the remainder were fresh water. The ion concentration of the groundwater along the riverbed and near the southern margin of the basin were lower than those farther away from the riverbed. The groundwater in the study area was of Na+-HCO(3)(-)type near the bank of the Heihe River and in the southern margin of the basin, while Na+-SO42--Cl(-)type samples were observed in the terminal lake region. In the desert area the groundwater reached a TDS of 3,000-6,000 mg/L and was predominantly by a Na+-Cl(-)chemistry. Br/Cl for the water of Ejina Basin indicates an evaporite origin for the groundwater with a strongly depleted Br/Cl ratio (average 0.000484). The surface water was slightly enriched in Br/Cl (average 0.000711) compared with groundwater. The calculated saturation index (SI) for calcite and dolomite of the groundwater samples range from -0.89 to 1.31 and -1.67 to 2.67 with averaged 0.24 and 0.61, respectively. About 97 percent of the groundwater samples were kinetically oversaturated with respect to calcite and dolomite, and all the samples were below the equilibrium state with gypsum. Using isotope and hydrochemical analyses, this study investigated the groundwater evolution and its residence time. The groundwater content was mainly determined by the dissolutions of halite, gypsum, and Glauber's salt (Na2SO4), as well as Na+ exchange for Ca2+, and calcite and dolomite precipitation. With the exception of a few locations, most of the groundwater samples were suitable for irrigation uses. Most of the stable isotope compositions in the groundwater sampled plotted close to the Global Meteoric Water Line (GMWL), indicating that the groundwater was mainly sourced from meteoric water. There was evidence of enrichment of heavy isotopes in the groundwater due to evaporation. Based on the tritium content in atmospheric precipitation and by adopting the exponential-piston model (EPM), the mean residence time of the unconfined aquifer groundwater was evaluated. The results show that these groundwaters have low residence time (12 to 48 years) and are renewable. In contrast, the confined groundwater had C-14 ages estimated by the Pearson model between 4,087 to 9,364 years BP. Isotopic signatures indicated formation of deep confined groundwaters in a colder and wetter climate during the late Pleistocene and Holocene.
英文关键词	water chemistry; environmental isotope; tritium dating technology; groundwater recharge; Ejina Basin
WOS研究方向	Physical Geography
WOS类目	Geography, Physical
WOS关键词	RIVER-BASIN ; EVOLUTION ; WATER ; RESOURCES ; RECHARGE
WOS记录号	WOS:000422281700002
来源期刊	SCIENCES IN COLD AND ARID REGIONS
来源机构	中国科学院西北生态环境资源研究院
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/239385
作者单位	[Su, YongHong; Feng, Qi; Chang, ZongQiang; Si, JianHua; Cao, ShengKui; Xi, HaiYang; Guo, Rui] Chinese Acad Sci, Cold & Arid Reg Environm & Engn Res Inst, 320 West Donggang Rd, Lanzhou 730000, Gansu, Peoples R China
推荐引用方式 GB/T 7714	Su, YongHong,Feng, Qi,Chang, ZongQiang,et al. Characterization of groundwater in the Ejina Basin, northwest China: hydrochemical and environmental isotopes approaches[J]. 中国科学院西北生态环境资源研究院,2010,2(6).
APA	Su, YongHong.,Feng, Qi.,Chang, ZongQiang.,Si, JianHua.,Cao, ShengKui.,...&Guo, Rui.(2010).Characterization of groundwater in the Ejina Basin, northwest China: hydrochemical and environmental isotopes approaches.SCIENCES IN COLD AND ARID REGIONS,2(6).
MLA	Su, YongHong,et al."Characterization of groundwater in the Ejina Basin, northwest China: hydrochemical and environmental isotopes approaches".SCIENCES IN COLD AND ARID REGIONS 2.6(2010).