AWWA WQTC58905

The occurrence and health risk from human enteric viruses is increasingly becoming a concern for drinking water utilities, particularly because the availability of molecular techniques makes it possible to monitor for these organisms. Viruses are a concern in groundwater because of the their small size and mobility in porous media. A national study was conducted to monitor the occurrence of enteric viruses in the continental United States. Groundwater samples from 448 sites, from 35 states were assayed for enteric viruses by cell culture and RT-PCR. Twenty-one sites (4.8%) were positive for virus by cell culture and 141 sites (31.5%) were positive for viruses by RT-PCR. Routine monitoring of groundwater for fecal contamination may soon be a requirement for water utilities under the proposed Ground Water Rule by US Environmental Protection Agency. Choosing the appropriate indicator system to determine the vulnerability of groundwater supplies to viral contamination is important to the successful implementation of the Ground Water Rule. Twenty groundwater sites from the national study were monitored monthly, for 1 year to develop a useful microbial indicator for assessing the vulnerability of groundwater at risk of fecal contamination. Human enteric viruses were detected either by cell culture of RT-PCR on at least one occasion in 17 of the 20 wells. The results suggest that both bacterial indicators and coliphage would be useful indicators for monitoring the vulnerability of groundwater sources. The detection of microbial indicators on at least one occasion in all of the wells tested supports the need for disinfection of all groundwater supplies. Includes 11 references, tables, figure.