城市岩溶地下水人为源稀土元素研究——以贵阳市为例

Anthropogenic Rare Earth Elements of Karst Groundwater in Urban Area:Taking Guiyang City as An Example

随着稀土元素在现代工业、医疗领域的广泛应用,越来越多的被带入天然水环境中,已经被认为是一种潜在的新兴微污染物。以贵阳市为研究对象,分析了地下水样品中稀土元素含量、澳大利亚后太古宙页岩(PAAS)标准化配分模式及人为源稀土元素特征,结果表明:贵阳市地下水中∑REE含量在6.9~155.5 ng/L之间,均值为24.7 ng/L,总体表现为中、重稀土元素相对于轻稀土元素富集,且具有显著的Ce负异常和Eu正异常特征。贵阳市各区域地下水中均发现有Gd正异常,人口密集、人类活动强烈的城市中心区域Gd异常值普遍较高,而人口相对稀少、人为干扰因素较少的区域中Gd异常则相对较低;人为源Gd占比在7.4%~96.0%之间,高人为源Gd比例反映了岩溶地下水受到了更为强烈的地表生活废水、医疗废水影响。本研究表明,人为源Gd在岩溶地下水污染示踪中具备良好的应用潜力。

With the wide application of rare earth elements(REEs)in modern industry,medical field,more and more are brought into the natural water environment,has been considered as a potential emerging micropollutants.Taking Guiyang city as the research object,this study analyzed the contents of REEs,the Post Archean Australian Shale(PAAS)standardized distribution pattern and characteristics of anthropogenic REEs in groundwater samples.The results show that the ΣREE scontent in groundwater in Guiyang City is 6.9-155.5 ng/L,with an average of 24.7 ng/L.The overall performance is that the medium and heavy REEs are enriched relative to the light REEs and have obvious negative Ce anomalies and positive Eu anomalies.Positive Gd anomalies were found in groundwater in all regions of Guiyang.The Gd anomalies in the urban center area with dense population and strong human activities were generally higher,while the Gd anomalies in the area with relatively small population and less human disturbance factors were relatively low.The proportion of anthropogenic Gd is between 7.4%-96.0%.The high proportion of anthropogenic Gd reflects that karst groundwater is affected by more intense surface domestic wastewater and medical wastewater.This study shows that anthropogenic Gd has good application potential in karst groundwater pollution tracing.