珠江源区小黄泥河流域地表水水化学组成特征及控制因素

Hydrochemical Composition Characteristics and Control Factors of Xiaohuangni River Basin in the Upper Pearl River

为研究小黄泥河流域地表水水化学组成特征及离子来源,服务小黄泥河流域水资源管理,系统采集了小黄泥河干流及支流河水和矿坑水样品,综合利用Piper三线图、Gibbs图解、离子比例系数和数理统计等方法,分析了小黄泥河河水的水化学组成、空间分布特征和主要控制因素,并评估了不同来源对溶质的贡献率.结果表明,小黄泥河流域河水pH值总体呈弱碱性,变化范围7.17~9.14,均值为8.00;TDS值变化范围为154~460 mg·L^(-1),均值为257.39 mg·L^(-1),与西江干流相当;优势阳离子为Ca^(2+),占阳离子总和的69%;优势阴离子为HCO_(3)-和SO_(4)^(2-),分别占阴离子总和的65%和30%.小黄泥河干流水化学类型主要为HCO_(3)-Ca型,受矿业活动影响,支流河水从HCO_(3)-Ca型过渡为HCO_(3)·SO_(4)-Ca和HCO_(3)·SO_(4)-Ca·Na型.河水溶质主要受到硫酸和碳酸参与的碳酸盐岩和硅酸盐岩风化的控制,其中碳酸盐岩风化对河水离子组分贡献率为63%,硅酸盐岩风化贡献率为16.33%;人类活动对小黄泥河流域河水溶质的影响也不容忽视,其中矿业活动贡献率为13.4%,农业活动和生活污水的贡献率为4%.

In order to serve the water resources management of the Xiaohuangni River basin,this study explored the hydrochemical composition characteristics and ion sources of surface water in the basin.Samples of main stream and tributary river water and mine water were systematically collected.By means of a Piper diagram,Gibbs diagram,ion ratio coefficient,and mathematical statistical analysis,we analyzed the hydrochemical composition,spatial distribution characteristics,and main control factors of the Xiaohuangni River and evaluated the solute contribution rates of different sources.The results showed that the pH of the Xiaohuangni River basin ranged between 7.17 to 9.14,with an average of 8.00,which is generally considered weakly alkaline.Additionally,the total dissolved solids ranged between 154 mg·L^(-1) to 460 mg·L^(-1),with an average of 257.39 mg·L^(-1),which was equivalent to that of the main stream of the Xijiang River.The dominant cation was Ca^(2+),accounting for 69%of the total cations;the dominant anions were HCO_(3)-and SO_(4)^(2-),accounting for 65%and 30%of the total anions,respectively.The main chemical type of the main stream was HCO_(3)-Ca.Affected by mining activities,the tributaries transitioned from HCO_(3)-Ca to HCO_(3)·SO_(4)-Ca and HCO_(3)·SO_(4)-Ca·Na type.River water solute was mainly controlled by the weathering of carbonate rock and silicate rock,with the participation of sulfuric and carbonic acid.The contribution rate of carbonate weathering to river water solute was 63%,and that of silicate weathering was 16.33%.Meanwhile,human activities contributed markedly to the dissolved solutes of the Xiaohuangni River basin,in which the contribution rate of mining activities was 13.4%,and the contribution rate of agricultural activities and domestic sewage was 4%.