黔西拖长江流域水化学演化特征及驱动因素

拖长江为黔西典型的矿业型岩溶山地小流域，研究其水化学演化特征及驱动因素，对当地经济社会发展和水资源科学管理均具有重要的意义.通过采集拖长江流域河水、泉水和矿井水样品，利用水化学图解、数理统计和绝对因子分析-多元线性回归受体模型(APCS-MLR),研究了拖长江流域河水溶质来源及其对河水水化学组分的贡献.拖长江流域河水pH值为7.30～8.31,TDS值为40～520 mg·L^-1,TDS主要由Ca²⁺、 Na⁺、 HCO^-₃和SO₄^2-贡献.河水优势阳离子为Ca²⁺和Na⁺,优势阴离子为HCO^-₃和SO₄^2-,水化学类型从HCO₃-Ca过渡为HCO₃-Ca·Na和HCO₃·SO₄-Ca·Na型；矿井水主要为HCO

Characteristics and Driving Factors of Hydrochemical Evolution in Tuochangjiang River Basin, Western Guizhou Province

Tuochangjiang River is a typical mining-type watershed in the karst mountainous area of western Guizhou province. The study of its hydrochemical evolution characteristics and driving factors is of great significance to the local economic development and the scientific management of water resources. The samples of river water, spring water, and mine water in the Tuochangjiang River Basin were collected, and the sources of solutes and their contribution to the chemical components of river water were discussed by means of hydrochemical diagrams, mathematical statistics, and the absolute principal component scores-multivariate linear regression model (APCS-MLR). The results showed that the pH of the river water ranged between 7.30 to 8.31, and the TDS value ranged between 40 to 520 mg·L^-1, which was mainly contributed by Ca²⁺, Na⁺, HCO₃^-, and SO₄^2-. The dominant cations in river water were Ca²⁺ and Na⁺, the dominant anions were HCO₃^- and SO₄^2-, and the main water chemistry transitioned from HCO₃-Ca to HCO₃-Ca·Na and HCO₃·SO₄-Ca·Na type, whereas that of the mine water was mainly the HCO₃-Na and HCO₃·SO₄-Na types. The chemical composition of river water was affected by rock weathering, exchange adsorption of anions, mineral dissolution and precipitation, and human activities, in which Ca²⁺, Mg²⁺, and HCO₃^- were mainly derived from the weathering and dissolution of carbonate and silicate rocks, Na⁺and SO₄^2- were mainly from the discharge of mining wastewater, and Cl^- and NO₃^- were affected by domestic sewage and agricultural activities, respectively. APCS-MLR analysis further showed that the river water solutes mainly included five sources:discharge of mining wastewater, dissolution of soil minerals, geological background, agricultural activities, and unknown sources, and their contribution rates to river water were 23.49%, 35.04%, 13.87%, 7.96%, and 20.63%, respectively. Mining factors and soil factors were the most important sources of solutes in the river water, and they were the main driving factors for the hydrochemical evolution of the Tuochangjiang River Basin.