Submitted to: Ground Water
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/1/2013
Publication Date: 3/3/2014
Citation: Hunt, R.J., Borchardt, M.A., Bradbury, K.R. 2014. Viruses as groundwater tracers: using ecohydrology to characterize short travel times in aquifers. Ground Water. 52:187-193. Interpretive Summary: Two key questions when investigating pathogens in the environment are: Where is the contamination source? How long does it take for pathogens to move from the source to the point of the next infection, for example, a drinking water well? Our study team developed the idea of using human viruses as natural tracers to answer these questions for fecal contamination of groundwater. Different gastrointestinal viruses will infect and then disappear from a population over time. During these times of infections viruses are shed in fecal wastes. Because the types of viruses being shed vary with time, the viruses measured in wastewater become a "virus signature" for a specific point in time, which then can serve as a tracer for tracking virus movement and inferring time-of-travel. This idea worked better than expected; the research team showed strong temporal correlation between the viruses in Madison, WI wastewater and city wells with a travel time of only two to four weeks. The viruses as tracer approach can be applied to other settings and pathogen types to understand the transport and fate of microbial contaminants from other sources, for example, manure in agricultural runoff or septic systems. Such knowledge is important for identifying opportunities for interrupting the fecal-oral cycle and preventing disease transmission in people and livestock.
Technical Abstract: Viruses are attractive tracers of short (<3 yr) travel times in aquifers because they have unique genetic signatures, are detectable in trace quantities, and are mobile and stable in groundwater. Virus “snaphots” result from infection and disappearance over time as a community develops resistance. The virus signature shed by an infected population at a specific point in time can then serve as a tracer for tracking virus and groundwater movement. The virus tracing approach and an example application are described to illustrate their ability to characterize travel times in large groundwater velocity settings and to provide insight unavailable from current methods.