关中盆地潜水环境背景值研究

Environmental background values of shallow groundwater in the Guanzhong Basin

依据关中盆地内487组水质检测数据,在深入分析关中盆地地下水流场、补给径流排泄条件和地下水环境状况的基础上,对研究区进行了较为详细的地下水环境单元划分,运用迭代标准差法和计算分布函数法,求取了关中盆地潜水主要常量组分K^＋＋Na^＋、Ca^2＋、Mg^2＋、Cl^-、SO4^2-、HCO3^-、TDS的环境背景值,分析了各组分背景值的空间分布规律及形成因素。结果表明：地下水补、径、排条件和水文地球化学作用对区内主要常量组分背景值的空间分布起主要控制作用,其中区内阴离子以HCO3^-为主,阳离子渭河北岸以K^＋＋Na^＋为主,渭河南岸以Ca^2＋为主;在渭河以北地区水文地球化学作用主要以矿化和蒸发浓缩作用为主,渭河以南地区以溶滤作用为主。其结果为关中盆地地下水污染评价、水资源开发与保护等提供了科学依据。

Relatively detailed environmental units of shallow groundwater were divided in the Guanzhong Basin on the basis of the intensive study of groundwater flow field,recharge and discharge conditions and groundwater environment.Natural background levels of K^＋＋Na^＋,Ca^2＋,Mg^2＋,Cl^-,SO4^（2-）,HCO3^-,TDS of different units were calculated by using the iterative 2-σtechnique,the calculated distribution function,and the spatial distribution regularity of background levels for major components as well as its controlling factors were discussed on the basis of 487 groundwater samples collected from the Guanzhong Basin.The results indicated that the spatial distribution of the major components was mainly controlled by groundwater recharge,runoff,discharge and hydrogeochemical process,in which the anion in the area was mainly HCO3^-,the cation in the north shore of Weihe was mainly K＋＋Na＋while in the south shore of Weihe was mainly Ca^2＋;moreover,the hydrogeochemical process in the northern area of Weihe was mainly mineralization and evaporation,and in the southern area of Weihe was mainly lixiviation.The results obtained provide scientific reference for the evaluation of groundwater contamination and the future development and protection of water resources.