Human Enteric Viruses in Groundwater from a Confined Bedrock Aquifer

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• 作者：Mark A. Borchardt ; Kenneth R. Bradbury ; Madeline B. Gotkowitz ; John A. Cherry ; Beth L. Parker
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：September 15, 2007
• 年：2007
• 卷：41
• 期：18
• 页码：6606 - 6612
• 全文大小：177K
• 年卷期：v.41,no.18(September 15, 2007)
• ISSN：1520-5851

文摘

Confined aquifers are overlain by low-permeabilityaquitards that are commonly assumed to protect underlyingaquifers from microbial contaminants. However, empiricaldata on microbial contamination beneath aquitards islimited. This study determined the occurrence of humanpathogenic viruses in well water from a deep sandstoneaquifer confined by a regionally extensive shale aquitard.Three public water-supply wells were each sampled 10times over 15 months. Samples were analyzed by reversetranscription-polymerase chain reaction (RT-PCR) forseveral virus groups and by cell culture for infectiousenteroviruses. Seven of 30 samples were positive by RT-PCR for enteroviruses; one of these was positive for infectiousechovirus 18. The virus-positive samples were collectedfrom two wells cased through the aquitard, indicating theviruses were present in the confined aquifer. Samplesfrom the same wells showed atmospheric tritium, indicatingwater recharged within the past few decades. Hydrogeologicconditions support rapid porous media transport ofviruses through the upper sandstone aquifer to the top ofthe aquitard 61 m below ground surface. Natural fracturesin the shale aquitard are one possible virus transport pathwaythrough the aquitard; however, windows, cross-connectingwell bores, or imperfect grout seals along well casingsalso may be involved. Deep confined aquifers can be morevulnerable to contamination by human viruses thancommonly believed.