Human enteric viruses in groundwater from a confined bedrock aquifer
Human enteric viruses in groundwater from a confined bedrock aquifer
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DOI：
10.1021/es071110
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发表时间：
2007-09-15
影响因子：
11.4
通讯作者：
Parker, Beth L.
中科院分区：
文献类型：
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作者：
Borchardt, Mark A.;Bradbury, Kenneth R.;Parker, Beth L.
承压含水层上覆着低渗透性的含水层，通常认为这些含水层是为了保护下面的含水层不受微生物污染。然而，弱透水层下微生物污染的经验数据有限。这项研究确定了人类致病病毒的发生井水从深砂岩含水层的区域广泛的页岩弱透水层。在15个月内对三口公共供水威尔斯井各取样10次。通过逆转录-聚合酶链反应（RT-PCR）分析样品中的几种病毒组，并通过细胞培养分析感染性肠道病毒。30份样品中有7份通过RTPCR检测肠道病毒呈阳性;其中1份为传染性埃可病毒18阳性。从两口穿过弱透水层的威尔斯井中采集病毒阳性样品，表明承压含水层中存在病毒。来自同一口威尔斯井的样本显示大气中含有氚，这表明水在过去几十年中被重新注入。水文地质条件支持病毒通过上部砂岩含水层到地面以下61米的弱透水层顶部的快速多孔介质运输。页岩弱透水层中的天然裂缝是通过弱透水层的一种可能的病毒运输途径;然而，也可能涉及沿着井套管的窗口、交叉连接的井筒或不完善的灌浆密封。深层承压含水层可能比通常认为的更容易受到人类病毒的污染。
Confined aquifers are overlain by low-permeability aquitards that are commonly assumed to protect underlying aquifers from microbial contaminants. However, empirical data on microbial contamination beneath aquitards is limited. This study determined the occurrence of human pathogenic viruses in well water from a deep sandstone aquifer confined by a regionally extensive shale aquitard. Three public water-supply wells were each sampled 10 times over 15 months. Samples were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) for several virus groups and by cell culture for infectious enteroviruses. Seven of 30 samples were positive by RTPCR for enteroviruses; one of these was positive for infectious echovirus 18. The virus-positive samples were collected from two wells cased through the aquitard, indicating the viruses were present in the confined aquifer. Samples from the same wells showed atmospheric tritium, indicating water recharged within the past few decades. Hydrogeologic conditions support rapid porous media transport of viruses through the upper sandstone aquifer to the top of the aquitard 61 m below ground surface. Natural fractures in the shale aquitard are one possible virus transport pathway through the aquitard; however, windows, cross-connecting well bores, or imperfect grout seals along well casings also may be involved. Deep confined aquifers can be more vulnerable to contamination by human viruses than commonly believed.