Bradbury, K. R.; Borchardt, Mark A.; Gotkowitz, Madeline B.; Hunt, R. J. / Assessment of virus presence and potential virus pathways in deep municipal wells
Abstract, pp. 2-3 PDF (761.9 KB)
component of recharge to most of the wells sampled. Virus levels in surface water were much lower than in sewage, thus significant volumes of lake water would be required to produce the virus levels measured in the wells. The most likely source of the viruses in the wells is the leakage of untreated sewage from the Madison sewer system. Given the high concentrations (millions of genomic copies per liter) of viruses in sewage, it would take very little sewage to produce the virus concentrations observed in the wells. Human enteric viruses might be excellent tracers of recently recharged groundwater in urban settings if virus sources exist. They have the desirable tracer characteristics of detectability over several orders of magnitude, high mobility, and are time-specific due to constantly changing serotypes. Although the presence of detectable tritium in a well is almost always an indicator of recent recharge to the well, the absence of tritium (at a detection limit of 0.8 TU) does not necessarily indicate that the well will be virus-free. In fact detection of viruses many be a far more sensitive indicator than tritium of a proportion of "young" groundwater in a well.