Water-borne diseases

Human viruses in deep groundwater threaten drinking water supplies

Researchers testing deep aquifers used for drinking water found human viruses, challenging the assumption that these crucial water supplies are protected from surface contamination.

Samples from three public water supply wells that draw from a 240-foot deep aquifer in Wisconsin contained human intestinal viruses, which as a group are associated with diseases such as meningitis, encephalitis, newborn enteroviral disease and polio.

Deep aquifers are a source of drinking water for many people.

Context:

Municipal drinking water wells are often drilled deep into the ground to reach aquifers lying under relatively impermeable layers called aquitards. Aquifers bounded above and below by aquitards are called contained aquifers. The aquitards are thought to protect the aquifers from surface contamination.

Shallow groundwater near waste water injection well sites can contain bacteria and viruses. Injecting waste water from treatment plants into the ground to recharge wells continues even though it's been known for 30 years that the recharged well water can be contaminated with pathogens (Vaughn et al. 1978). Bacteria found in human intestines have been measured as well in aquifers in the United Kingdom (Powell et al. 2003).

Viruses have a greater likelihood of reaching aquifers to contaminate drinking water than bacteria, protozoa and other waterborne, disease-causing organisms because their small size may allow them to pass through aquitards to reach aquifer waters. Until now, this possibility has not been tested explicitly. In a survey of over 400 sites across the United States, groundwater samples tested positive for at least one virus type (Abbaszadegan et al. 2003). This study, however, did not identify which of the aquifers were contained aquifers. Researchers testing deep aquifers used for drinking water found human viruses, challenging the assumption that these crucial water sup... more

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