School of Environmental Science and Engineering, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China.
Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education, Chang'an University, No. 126 Yanta Road, Xi'an 710054, Shaanxi, China.
Int J Environ Res Public Health. 2019 Apr 27;16(9):1492. doi: 10.3390/ijerph16091492.
Groundwater is the major water resource for the agricultural development of the Guanzhong Basin, China. In this study, a total of 97 groundwater samples (51 from the North Bank of the Wei River (NBWR) and 46 from the South Bank of the Wei River (SBWR)) were collected from the central-western Guanzhong Basin. The aim of this study was to investigate the hydrogeochemical characteristics of the basin and to determine the suitability of shallow groundwater for irrigation. The groundwater of the entire study area is alkaline. The groundwater of the SBWR is fresh water, and the NBWR groundwater is either freshwater or brackish water. The average concentration of ions (except for Ca) in SBWR samples is lower than in NBWR samples. HCO is dominant in the groundwater of the study area. Ca is dominant in the SBWR while Na is dominant in the NBWR. The SBWR groundwater is mainly of the HCO-Ca·Mg type, and has undergone the main hydrogeochemical processes of rock weathering-leaching. The hydrochemical facies of the majority of the NBWR groundwater samples are the HCO-Na type with several minor hydrochemical facies of the HCO-Ca·Mg, SO·Cl-Na, and SO·Cl-Ca·Mg types. Its chemistry is mainly controlled by rock weathering, cation exchange, and evaporation. Salinity hazard, sodium percentage, sodium adsorption ratio, residual sodium carbonate, magnesium hazard, permeability index, Kelley's ratio, potential salinity, synthetic harmful coefficient, and irrigation coefficient were assessed to evaluate the irrigation quality of groundwater. The results of the comprehensive consideration of these indicators indicate that the percentage of NBWR water samples suitable for irrigation purposes ranges between 15.7% and 100% at an average level of 56.7%. Of the SBWR water samples suitable for irrigation, the percentage ranges from 78.3% to 100% with an average of 91.8%. Land irrigated with such water will not be exposed to any alkali hazard, but will suffer from a salinity hazard, which is more severe in the NBWR. Thus, most of the water in the NBWR can be used for soils with good drainage conditions which control salinity.
地下水是中国关中盆地农业发展的主要水资源。本研究共采集了关中盆地中西部地区 97 个地下水样本（北岸 51 个，南岸 46 个）。本研究旨在调查盆地的水文地球化学特征，并确定浅层地下水的灌溉适宜性。整个研究区地下水呈碱性。南岸地下水为淡水，北岸地下水为淡水或微咸水。南岸水样中除 Ca 以外的离子平均浓度均低于北岸水样。HCO 是研究区地下水的主要阴离子。Ca 是南岸地下水的主要阳离子，而 Na 是北岸地下水的主要阳离子。南岸地下水主要为 HCO-Ca·Mg 型，经历了岩石风化淋滤的主要水文地球化学过程。大部分北岸地下水水样的水化学相为 HCO-Na 型，少数为 HCO-Ca·Mg、SO·Cl-Na 和 SO·Cl-Ca·Mg 型。其化学性质主要受岩石风化、阳离子交换和蒸发的控制。采用盐度危害、钠百分比、钠吸附比、剩余碳酸钠、镁危害、渗透率指数、凯利比、潜在盐度、综合有害系数和灌溉系数等指标评价地下水灌溉水质。综合考虑这些指标的结果表明，北岸地下水样本中适宜灌溉的百分比在平均水平 56.7%的基础上，在 15.7%到 100%之间变化。南岸地下水样本中适宜灌溉的百分比在 78.3%到 100%之间，平均值为 91.8%。用这样的水灌溉的土地不会受到任何碱害，但会受到盐害，北岸的盐害更为严重。因此，北岸的大部分水可以用于具有良好排水条件的土壤，以控制盐分。
