摘要:
陕西泾阳南部是典型的黄土分布区、人口居住聚集区、农业活动密集区、地质灾害频发区，研究该区地下水水文地球化学成因机制及次生环境挑战，对黄土高原地下水资源开发利用、用水安全保障和生态地质环境保护具有重要意义。基于区内地下水调查、水样采集与分析，查明地下水主要离子分布特征；综合运用水化学方法和同位素理论，揭示地下水水文地球化学成因机制及其主控因子；借助综合权重水质指数、镁系数、钠百分比、Wilcox图、灌溉系数，综合评估地下水的饮用和灌溉适宜性，进而阐释其次生环境挑战。结果表明：研究区地下水整体呈弱碱性，泾河南岸为淡水和微咸水，北岸属微咸水和咸水；地下水优势阳离子为Na+和Mg2+，优势阴离子为HCO3-与SO42-，水化学类型以HCO3·SO4-Na·Mg和HCO3·SO4·Cl-Na·Mg型为主，且北岸的水化学类型更复杂。水化学特征主控于岩石风化作用，其中硅酸盐岩的风化溶解作用为主导；蒸发浓缩作用与阳离子交替吸附作用促进了地下水咸化；南岸地下水受农业活动影响显著，北岸地下水受工业活动、生活污水与人畜粪肥的综合影响。饮用水质等级以中等为主，引起健康风险的首要因子为总硬度、NO3-、F-和SO42-；大部分地下水不适宜直接灌溉，需采取措施，防止累盐，否则会诱发土壤盐渍化。建议在区内开展地下水污染防治工作，以免面临更严峻的次生环境挑战。
Abstract:
The southern Jingyang, Shaanxi Province is a typical loess distribution area, population gathering area, agricultural activity intensive area, and geological disaster prone area. Thus, studying the hydrogeochemical genesis mechanism and secondary environmental challenges of groundwater in this area is of great significance for the development and utilization of groundwater resources, water safety guarantee, and ecological geological environment protection on the Chinese Loess Plateau. Based on groundwater investigation, water sample collection and analysis in the area, the main ion distribution characteristics of groundwater were identified; the hydrogeochemical genesis mechanism and its main controlling factors of groundwater were revealed by the comprehensive application of hydrochemical methods and isotope theory; the suitability of groundwater for drinking and irrigation was comprehensively evaluated, and its secondary environmental challenges were explained, using the integrated-weight water quality index, magnesium hazard, soluble sodium percentage, Wilcox plot, and irrigation coefficient. The results indicate that the groundwater in the study area was generally weakly alkaline, with freshwater and brackish water in the south bank of the Jing River and brackish water in the north bank; The dominant cations in groundwater were Na+ and Mg2+, and the dominant anions were HCO3- and SO42-; The hydrochemical types were mainly HCO3·SO4-Na·Mg and HCO3·SO4·Cl-Na·Mg, and the hydrochemical types in the north bank were more complex. The hydrochemical characteristics of groundwater are mainly controlled by rock weathering, among which the weathering and dissolution of silicate rocks were dominant. Meanwhile, the evaporation and cation alternating adsorption promoted the salinization of groundwater. The groundwater in the south bank was significantly affected by agricultural activities, while the groundwater in the north bank was influenced by a combination of industrial activities, domestic sewage, and human and animal manure. The drinking water quality level was mainly moderate, and the primary factors causing health risks were total hardness, NO3-, F-, and SO42-. Most groundwater was not suitable for direct irrigation and measures need to be taken to prevent salt accumulation, otherwise soil salinization may occur. It is recommended to carry out the work of groundwater pollution prevention and control in this area to avoid facing more severe secondary environmental challenges.
下载:
