苏锡常地区浅层地下水质量演变及影响因素识别

Evolution of shallow groundwater quality and identification of influencing factors in Suzhou-Wuxi-Changzhou area

结合苏锡常地区2009年和2019年315组浅层地下水样品的30项水化学指标资料,查明浅层地下水质量演变特征和超标指标,通过数理统计、因子分析法提取6个影响地下水水质的主要污染因子,解析地下水污染源及影响因素,利用因子得分绘制各污染源的污染空间分布,并进一步识别影响地下水水质的原生地质污染和人为活动污染及其空间变异性。结果表明:苏锡常地区浅层地下水水质整体呈改善趋势,超标指标主要包括锰、铁、耗氧量、碘化物、pH、总硬度、砷、铝、亚硝酸盐、硝酸盐和氨氮;提取的6个影响因子中F_(1)代表TDS、总硬度、氯化物和硫酸盐,主要为溶滤-富集作用,F_(2)和F_(3)为原生地质因子,受铁、锰、砷和碘化物影响,F_(4)、F_(5)和F_(6)为人为活动影响因子,影响指标包含耗氧量、氨氮、亚硝酸盐氮和铝。通过计算315组样品地下水污染综合得分,可知张家港沿江、苏州吴江南部受原生地质影响较为严重,其次是苏州主城区、太仓和昆山南部等地,综合污染严重区域主要分布在张家港沿江、昆山南部、无锡和苏州市区、吴江南部一带。研究结果可直观表示苏锡常地区原生地质影响和综合污染空间分布,对浅层地下水环境问题的精准定位和保护修复具有指导意义。

This study examined the characteristics of shallow groundwater quality evolution and exceedance indicators based on 30 chemical indicators in shallow groundwater samples collected from the Su-Xi-Chang area in 2009 and 2019.Using mathematical statistics and factor analysis,this study identified six major pollution factors(F_(1)-F_(6))that affect groundwater quality and analyzed the sources and factors of groundwater pollution.Factor scores were also used to map the spatial distribution of the different pollution sources.In addition,this study assessed the spatial variability of primary geological and anthropogenic pollution influencing groundwater quality.The results indicated that the overall quality of shallow groundwater in Su-Xi-Chang improved.Among the six factors,F_(1) represents TDS,total hardness,Cl_(-),and SO_(4)^(2-),which mainly reflect the effects of dissolution and filtration;F_(2) and F_(3) are the primary geological factors influenced by Fe,Mn,As,and I;and F_(4),F_(5),and F_(6) are anthropogenic factors influenced by COD_(Mn),NH_(4)^(-),NO_(2)^(-),and Al.The comprehensive pollution scores of 315 groundwater samples were calculated,and the areas most severely affected by primary geological factors were Zhangjiagang and the southern part of Wujiang,followed by the main urban areas of Suzhou,Taicang,and the southern part of Kunshan.Areas with severe comprehensive pollution were mainly located along the riverside of Zhangjiagang,southern Kunshan,Wuxi,Suzhou,and southern Wujiang.The results directly depict the spatial distribution of primary geological influences and comprehensive pollution in the Suzhou-Wuxi-Changzhou area,providing a valuable supplement to routine water quality evaluation and guidance for precise positioning,protection,and restoration of shallow groundwater environmental issues.