Citation:

FRANCY, D. S., R. N. BUSHON, E. J. LUZANO, E. BERTKE, AND G. FOUT. VIRAL PATHOGENS AND MICROBIOLOGICAL INDICATORS IN GROUND WATER FROM SMALL PUBLIC WATER SUPPLIES IN SOUTHEASTERN MICHIGAN. Presented at American Society for Microbiology Annual Meeting, Atlanta, GA, June 05 - 09, 2005.

Impact/Purpose:

Overarching Objectives and Links to Multi-Year Planning

This task directly supports the Drinking Water Research Program Multi-Year Plan's long term goal to "develop scientifically sound data and approaches to characterize and manage risks to human health posed by exposure to waterborne pathogens and chemicals" under GRPA Goal 2 (Clean and Safe Water). The overarching objective is to provide the Office of Water, Agency risk assessors and managers, academics, the scientific community, state regulators, water industry and industry spokes groups with exploratory occurrence and exposure data on human enteric viruses. These data will improve the quality of risk-based assessments and tools used by the Agency to set regulations, policies and priorities for protecting human health and allow the Agency to assure the public that the appropriate methods are being used to demonstrate that drinking water is safe from pathogenic agents.

Specific Subtask Objectives:

o Conduct an exploratory occurrence studies on emerging human waterborne pathogenic viruses and viruses on the Contaminant Candidate List (CCL) in water (Subtask A; to be completed by 9/05 in support of LTG 1 (due 2010)).

o Determine the relationship of bacterial virus indicators to human enteric virus occurrence in the above studies (Subtask A; to be completed by 9/05 in support of LTG 1 (due 2010)).

o Develop a non-invasive assay for measuring human exposure to viruses (Subtask B; to be completed by 9/05 in support of LTG 1 (due 2010)).

Description:

Thirty-eight public ground-water-supply wells serving less than 3,300 people were sampled from July 1999 through July 2001 in southeastern Michigan to determine (1) occurrence of viral pathogens and microbiological indicators, (2) whether indicators are adequate predictors of the presence of viruses, and (3) the factors that affect the presence of viruses. Samples were analyzed for enteric viruses by reverse transcriptase-polymerase chain reaction (RT-PCR), for culturable viruses by cell culture, and for the indicators total coliforms, E. coli, enterococci, and F-specific and somatic coliphage. Ancillary environmental and water-quality data also were collected.

A total of 169 regular samples and 32 replicate pairs were collected. Each well was sampled from one to five times. By use of RT-PCR, enterovirus was found in four wells (10.5%) and hepatitis A virus (HAV) in five wells (13.2 %). Culturable viruses were found once in two wells (5.9%), and neither of these wells was positive for viruses by use of RT-PCR. Nine of the 38 wells (23.7%) were positive for viruses by either RT-PCR or cell culture. One or more indicators were found in 18 of 38 wells. Total coliforms, E. coli, enterococci, and F-specific and somatic coliphage were found in 34.2, 10.5, 15.8, 5.9, and 5.9%, respectively, of the wells tested. Five out of nine (55.6%) virus-positive wells were also found to be positive for an indicator.

More virus-positive samples were found at sites served by septic systems than those served by sewerlines. Statistically significant relations were found between total coliforms and dissolved organic carbon, iron, or chloride concentrations. Presence of nitrate was related to presence of E. coli, enterococci, coliphage, or enteric viruses but not to total coliforms.

This study provides evidence for fecal contamination of ground water at small public-supply wells and shows the importance of collecting multiple samples at each site. The study also suggests that the collection of site-characteristic data (e.g., population density, land usage, hydrogeology, well construction), data on multiple water-quality parameters (e.g., mineral and organic carbon concentrations) and data on microbiological indicators is important for making reliable predictions of the presence of enteric viruses in small public water systems.

Record Details: