地下水质量影响因素识别与定量评价——以广西桂林会仙湿地为例

Identification and quantitative evaluation of influencing factors of groundwater quality——A case study of Huixian wetland,Guilin,Guangxi

近年来,在人类活动强烈的干扰下,湿地地下水环境日益恶化。传统的地下水质量评价方法因未区分天然高背景和人为污染的影响,评价结果不能全面、真实、可靠地表示出水质的实际状态。笔者等选取地下水主要超标指标进行因子分析,并根据各因子的得分和方差贡献率计算各采样点得分,并最终计算因子影响下的综合得分。综合评价结果表明,研究区地下水主要有3个影响因子,因子1主要为天然高背景引起的高铁(TFe),锰(Mn)和铝(Al),因子2为农业及生活污水影响导致的NH^(+)_(4)、高锰酸钾指数(COD_(Mn))和NO^(-)_(2)超标,因子3为天然与人为复合影响导致的I^(-)污染。计算得出的综合影响程度与传统的水质评价结果吻合,综合影响程度得分图不仅可以得出地下水质信息,还可根据确定的因子得出天然与人为对地下水质的影响。

Objectives:The groundwater environment of wetland has been deteriorating under the strong interference of human activities in recent years.Because of the traditional evaluation methods for groundwater quality do not distinguish the effects of high natural background and anthropogenic pollution,the evaluation results can not represent the real state of water quality comprehensively,faithfully and reliably.Methods:In the study,the principal component analysis was developed for factor analysis.The scores of each sampling point were calculated based on the score and variance contribution of each factor.The comprehensive score under the influence of factors was calculated.Results:The comprehensive evaluation results showed that there were three main factors affecting groundwater in the study area.Factor 1 contained high Fe,Mn and Al caused by natural high background.Factor 2 contained NH_(4)^(+),COD_(Mn) and NO_(2)^(-) exceeding the standard caused by agricultural and domestic sewage.Factor 3 was I^(-) pollution caused by a combination of natural and anthropogenic influences.Conclusions:The calculated comprehensive impact degree was consistent with the results of traditional water quality assessment.The score chart of comprehensive impact degree can not only evaluate groundwater quality,but also the natural and anthropogenic impacts on groundwater quality based on the identified factors.