摘要
江苏宿迁市中部某远离工业企业的监测井地下水砷(As)指标连续多期次超《地下水质量标准》(GB/T 14848—2017)Ⅳ类标准限值。为探究该监测井地下水As长期超标原因,通过在监测井附近新钻取岩芯沉积物中不同形态As的提取实验,结合新井和监测井中地下水的同步取样与水质参数的测试,系统分析了监测井点位地下水As超标的原因。研究结果发现,离监测井5 m处的新井地下水As质量浓度不超标,而监测井中As仍超标。对比新井和监测井的水质参数与沉积物中As的赋存形态发现,在还原性和弱碱性的环境条件下,地下水类型及地层沉积物中碳酸盐结合态的变化可能对地下水As质量分数有明显的影响,而铁-锰氧化物结合态与有机物-硫化物结合态的变化对As质量分数超标影响则有限。此外,不排除可能受到成井工艺不规范与监测井受到串层污染的影响。
The concentration of arsenic in a pressure-bearing monitoring well,which is far from an industrial enterprise in Suqian,Jiangsu Province,has exceeded the limit of ClassⅣset by“Standard for groundwater quality(GB/T 14848—2017)”for many consecutive periods,and the reasons for its excess are extremely important for understanding regional groundwater quality.In order to systematically analyze the causes of excessive arsenic in groundwater at monitoring sites,different forms of arsenic were extracted in newly drilled core sediments near monitoring wells,and simultaneous sampling of groundwater in new wells and monitoring wells and testing of water quality parameters were considered as well.The results showed that the arsenic content of the new well,5 m away from the monitoring well,did not exceed the standard,while the monitoring well still exceeded the standard.Comparing the water quality parameters of new wells and monitoring wells with the occurrence patterns of arsenic in sediments,we found that the changes of groundwater type and carbonate binding state in strata sediments may have obvious effects on groundwater arsenic exceeding the standard in reduced and weakly alkaline water environment,while the change of iron manganese oxide binding state and organic matter and sulfide binding state has limited impact on arsenic exceeding the standard.It is not excluded that the impact on arsenic exceeding came from non-standard well completion technology and cross contamination by neighbor layers.
作者
张斌
黄娟
李闯
吴到懋
柯婷婷
郭炳跃
唐梦涵
田涛
ZHANG Bin;HUANG Juan;LI Chuang;WU Daomao;KE Tingting;GUO Bingyue;TANG Menghan;TIAN Tao(Jiangsu Institute of Geological Exploration Technology,Nanjing,Jiangsu 210008,China;Jiangsu Provincial Environmental Monitoring Center,Nanjing,Jiangsu 210019,China;Jiangsu Ecological Assessment Center,Nanjing,Jiangsu 210036,China;Suqian Environmental Monitoring Center Station,Suqian,Jiangsu 223809,China)
出处
《环境监控与预警》
2023年第6期77-84,共8页
Environmental Monitoring and Forewarning
基金
江苏省生态环境科研课题(2020006)。
关键词
砷
地下水
赋存形态
沉积物
Arsenic
Groundwater
Chemical from
Sediment
