郑州市中牟县地下水水化学特征及控制因素

Research of groundwater chemical characteristics and controlling factors in Zhongmu County,Zhengzhou City

地下水是维持人类生存和发展的重要资源。近年来,由于人类活动的强烈干扰,导致地下水的水化学特征发生改变,严重影响了其使用价值和生态功能。本研究以郑州市中牟县作为研究地区,联合应用Piper三线图、Gibbs图、离子比例系数法和多元统计技术,探究该地区地下水化学演变特征及形成机制,结果表明,中牟县地下水主要的阳离子是Ca2+和Na+,主要的阴离子是HCO3−和Cl−。地下水主要的水化学类型为HCO3-Ca(Mg)型,占总水样的46.2%。农业用地受到施肥的影响,水化学类型出现了Cl型水(20.8%)和SO4型水(6.25%),住宅用地由于受到生活污水的影响,出现了高比例的Na型水(55.0%)。而在湿地,地下水受到黄河水和污水处理厂回水混合影响,导致其主要的水化学类型转变为HCO3-Ca(Mg)·Na型。中牟县地下水水化学组分主要控制因素是岩石风化作用,并且主要受控于硅酸盐岩风化,而人类活动对水化学组分也存在一定的影响。相关性分析表明,在不同土地利用类型下,除NH4+、NO3−和NO2−外,其余水化学组分之间表现出显著的正相关关系,表征它们主要来自地层岩石风化。NH4+和NO3−表现出显著的负相关关系,说明二者主要来自于化肥和生活污水。在农业用地和住宅用地中地下水可能发生强烈的硝化作用,但是,湿地地下水可能发生了反硝化作用。研究结果可为中牟县地下水可持续开发利用提供理论依据和数据支撑。

Groundwater is an important resource for human survival and development.In recent years,due to the strong interference of human activities,the hydrochemical characteristics of groundwater have changed,which has seriously affected its use value and ecological function.In this study,the evolution characteristics and formation mechanism of groundwater chemistry in Zhongmu County,Zhengzhou City,were analyzed by using Piper trilinear diagram,Gibbs diagram,ion proportion coefficient and multivariate statistical techniques.The results showed that the main cations of groundwater in the study area were Ca2+and Na+,and the anions were dominated by HCO3−and Cl−.The main hydrochemical type of groundwater was HCO3-Ca(Mg),which accounts for 46.2%of the total water samples.Affected by agricultural activities,Cl type water(20.8%)and SO4 type water(6.25%)were found in agricultural land.Residential land was affected by domestic sewage,Na type water(55.0%)accounted for a high proportion.However,in wetlands,groundwater was affected by the mixed action of Yellow River and sewage treatment water,resulting in the major hydrochemical type changed to HCO3-Ca(Mg)-Na.The main controlling factor for the chemical composition of groundwater in Zhongmu County was rock weathering(silicate rock weathering).Human activities also have an effect on the chemical composition of groundwater.Correlation analysis showed that the main groundwater hydrochemical components(except NH4+,NO3−and NO2−)in different land use type have a significant positive correlation,which indicated that they came from rock weathering.NH4+and NO3−showed a significant negative correlation,indicating that they mainly came from fertilizer and domestic sewage.Strong nitrification may occur in groundwater in agricultural and residential lands,while in wetlands,denitrification may occur in aquifers.The results can provide theoretical basis and data support for sustainable development and utilization of groundwater in Zhongmu County.