黔西南州典型岩溶区地下河水质特征分析及综合评价

Characterization and Comprehensive Evaluation of Water Quality of Underground Rivers in Typical Karst Areas in Qianxinan Prefecture

为研究贵州省黔西南州煤-锑集中矿区水质特征,沿龙摆尾和水鸭两条相邻岩溶地下河采集水样,利用Piper三线图、Gibbs模型与离子比值图对研究区地下水水化学特征进行分析,应用基于CRITIC法+层次分析法的模糊综合模型对两条岩溶地下河进行水质评价。分析结果显示,龙摆尾地下河主要以HCO_(3)-SO_(4)-Ca型水为主,水鸭地下河主要以HCO_(3)-Ca和SO_(4)-HCO_(3)-Ca型水为主,水文地球化学演化主要受碳酸盐岩风化作用控制。选取总Fe、总Mn、SO_(4)^(2-)、总Sb等9个因子作为评价指标,利用模糊综合评价法对两条相邻岩溶地下河进行水质评价,评价结果显示龙摆尾20%的水样呈Ⅲ~Ⅴ类水,不宜饮用,水鸭地下河水质优于龙摆尾地下河。对比评价结果可得,煤-锑矿集中开采使大量矿山排水涌入岩溶地下河系统,导致Fe、Mn、SO_(4)^(2-)、Sb等离子浓度超标,但不同的水文地质条件、岩溶发育状况以及周边矿区规模的大小造成的污染程度与污染范围存在显著差异。

To study the water quality characteristics in the coal-antimony concentrated mining area of Qianxinan Prefecture,Guizhou Province,water samples were collected along two adjacent karst underground rivers,Longbaiwei and Shuiya.The hydrochemical characteristics of groundwater in the study area were analyzed using Piper trilinear diagrams,Gibbs models,and ion ratio diagrams.A fuzzy comprehensive evaluation model based on the CRITIC method and the analytic hierarchy process(AHP) was applied to assess the water quality of the two karst underground rivers.The analysis results show that longbaiwei is mainly dominated by HCO_3-SO_4-Ca type water.In contrast,Shuiya is primarily dominated by HCO_3-Ca and SO_4-HCO_3-Ca type water,with the hydrogeochemical evolution mainly controlled by carbonate rock weathering.Nine factors,including Fe,Mn,SO_4~(2-),and Sb,were selected as evaluation indicators.The water quality of the two adjacent karst underground rivers was assessed using the fuzzy comprehensive evaluation method.The evaluation results show that 20% of the water samples from Longbaiwei are categorized as Class Ⅲ~Ⅴ,indicating unsuitability for drinking,while the water quality of the Shuiya underground river is better than that of the Longbaiwei underground river.Comparing the evaluation results,it is evident that the concentrated mining of coal-antimony has led to a large amount of mine drainage entering the karst underground river system,resulting in excessive concentrations of ions such as Fe,Mn,SO_4~(2-),and Sb.However,the degree and extent of pollution vary significantly due to differences in hydrogeological conditions,karst development status,and the scale of surrounding mining areas.