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WGNHS releases study of human virus occurrence in deep water-supply wells

WGNHS hydrogeologists Ken Bradbury and Madeline Gotkowitz, working with Dr. Randy Hunt from the US Geological Survey and Dr. Mark Borchardt and Susan Spencer at the Marshfield Clinic, have completed a one year study of the occurrence of viruses in deep water-supply wells.  Viruses in these wells were unexpected because the wells draw water from below a shale formation thought to provide protection from contamination.   During 2007 and 2008 the investigators sampled six deep municipal wells for viruses on a monthly basis.  They also collected virus samples from local lakes and from untreated sewage.

Viruses were detected at least twice in every one of the six wells, but no well was virus-positive in every sampling round.   Virus results varied significantly with time, and there was apparent correlation between virus levels in sewage, lakes, and groundwater. The most likely source of the viruses in the wells is the leakage of untreated sewage from the Madison sewer system.  The investigators stress that these viruses pose no threat to public health as long as the water is disinfected, as it is in Madison.

The final report from this project is available as WGNHS Open-File Report  2008-08 and can be downloaded here. This study was also the focus of an article by Ron Seely in the Wisconsin State Journal. [Used with permission of Ron Seely and the Wisconsin State Journal.]

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