贵州清水江流域丰水期水化学特征及离子来源分析

对清水江流域丰水期河水离子浓度及组成特征分析表明,流域水化学组成以Ca2+、HCO-3离子为主,其次为Mg2+、SO2-4;TDS均值213.96 mg·L-1,高于世界流域均值.根据海盐校正分析得出,研究区大气降水中海盐输入对流域水化学的贡献率为2.23%,低于世界河流均值3%.Gibbs图结合离子比值分析表明,流域水化学主要受碳酸盐岩风化影响,越往下游硅酸盐岩化学风化贡献越明显,碳酸和硫酸同时参与了流域岩石风化过程.离子来源分析表明,Ca2+、Mg2+、HCO-3离子主要来自于白云石、方解石等碳酸盐岩风化溶解,Na+、K+、Cl-主要来源于硅酸盐岩风化;SO2-4和NO-3主要来源于大气酸沉降和城镇废水输入.人为活动影响分析表明上游工矿企业活动对清水江流域水化学影响明显.

Hydrochemical Characteristics and Sources of Qingshuijiang River Basin at Wet Season in Guizhou Province

According to the ion content and chemical characteristic analysis of Qingshuijiang River water during wet season, the result shows that the chemical composition of the river water is dominated by Ca²⁺, HCO₃^-; Mg²⁺, and SO₄^2-. The TDS concentration (213.96mg ·L^-1) is significantly higher than the average value of rivers worldwide. Seawater correction approach (Cl^- normalized seawater ratios) was applied to estimate the contribution proportions of local precipitation to the solutes, and it is found that the contribution ratio of precipitation (2.23%) is lower than the average value (3%) of global catchments. Furthermore, Gibbs graph combining major ion element ratio analysis indicates that the catchment hydrochemistry is mainly originated from carbonate rock weathering, which becomes increasingly distinct as the river goes downstream. Both carbonic acid and sulfuric acid play crucial roles in the chemical weathering. Ion source analysis demonstrates that Ca²⁺, Mg²⁺, HCO₃^- are mainly derived from chemical weathering of carbonate mineral (Dolomite and Calcite); Na⁺, K⁺ and Cl^- are primarily contributed by silicate mineral weathering; SO₄^2- and NO₃^- stemmed are mainly from acid atmospheric deposition and from urban sewage input. Anthropogenic analysis suggests that the chemical composition of Qingshuijiang River is greatly impacted by the upriver industrial and mining enterprises activities.