Waterborne viruses, one of the leading causes of gastrointestinal illnesses, were measured in United States drinking water sources and finished water. Scientists used a combination of measurement and statistical techniques to overcome limitations to quantifying these viruses, thus offering an enhanced method for virus monitoring.
Bacterial and viral pathogens in drinking water have historically posed significant health risk to humans. Drinking water treatment, including filtration and disinfection, in the United States in the early 20th century is credited with dramatically reducing the incidence pathogens from incoming water to provide communities with safe drinking water. However, pathogens are still reported as one of the leading causes of gastrointestinal illnesses from drinking water ingestion.
Pathogens, including viruses, can enter drinking water sources (rivers, lakes, groundwater, and reservoirs) through runoff from urban and agricultural areas; leakage from sewers and septic systems, storm water, and sewer overflows; and treated wastewater. If the pathogens persist through treatment, they can contribute viruses to drinking water and result in human exposure.
Enteric viruses, those that can replicate in the human digestive track, are one of many pathogens that are monitored in the Nation’s drinking water. Typically, drinking water facilities estimate the removal efficiency of enteric viruses based on the presence of fecal indicator bacteria. However, fecal indicator bacteria presence is not always indicative of viral presence, given the different survival rates and transport mechanisms of bacteria and viruses.
When viruses are measured in water, a technique called polymerase chain reaction (PCR) or quantitative PCR (qPCR) is used. One advantage of the qPCR method is that it can quickly generate a sufficient amount of genetic material for analysis. However, virus occurrence and concentration may be underestimated owing to its multistep viral concentration process or to PCR inhibition, where chemicals in the water sample prevent generation of sufficient amounts of genetic material for analyses. These limitations present a challenge to accurate estimation of virus concentration in public drinking water supplies.
As a result, U.S. Environmental Protection Agency (EPA) and U.S. Geological Survey (USGS) scientists collaborated and developed a unique approach to better quantify virus occurrence and concentration in drinking water as part of a larger study on contaminants in drinking water in the United States. First, they measured the occurrence of five waterborne virus groups (adenovirus, norovirus GI, norovirus GII, entero-virus, and polyomavirus) from 25 drinking water treatment facilities across the United States using qPCR methods. Measurements included paired source (rivers, lakes, reservoirs, and groundwater) and treated water samples.
The results showed that treated drinking water had fewer viruses than source waters, indicating that treatment methods used at the facilities in this study were helpful in reducing the viruses measured. However, samples from all 25 water treatment plants had false negatives (determinization that there were no viruses present when viruses were present) due to inhibition, indicating that a method accounting for inhibition is important for better estimation of virus occurrence and concentrations in environmental waters.
The scientists applied a statistical model to account for factors affecting viral detection, including the measured sample inhibition and recovery efficiency. The qPCR data were converted to count data and input into the statistical model to calculate virus concentrations. By using a statistical framework that accounted for factors affecting viral detection, this study offers an alternative approach to estimate the occurrence and concentration of viral pathogens in environmental waters used as sources of drinking water.
This research is part of a long-term approach by the USGS Environmental Health Program's Infrastructure Team to understand microbial and chemical contaminants in drinking water and potential human exposure. It was supported by the USGS Environmental Health Programs (Toxic Substances Hydrology and Contaminant Biology) and the EPA.
Related research is listed below.
Drinking Water and Wastewater Infrastructure Science Team
Per- and Polyfluoroalkyl Substances (PFASs) detected in Source Waters and Treated Public Water Supplies
Occurrence of Avian Influenza Virus in Groundwater—Study Provides Baseline Data and Informs Future Studies
Study Highlights the Complexity of Chemical Mixtures in United States Streams
Understanding Chemical and Microbial Contaminants in Public Drinking Water
Swine Manure Application as a Source of Hepatitis E Virus and other Livestock-Related Pathogens
Assessing Environmental Chemical Mixtures in United States Streams
Below are publications associated with this research.
Kolpin, D.W., Glassmeyer, S.T., and Furlong, E.T., 2017, An introduction to joint research by the USEPA and USGS on contaminants of emerging concern in source and treated drinking waters of the United States: Science of the Total Environment, v. 579, p. 1608-1609, doi:10.1016/j.scitotenv.2016.03.052.
Estimating virus occurrence using Bayesian modeling in multiple drinking water systems of the United States
Nationwide reconnaissance of contaminants of emerging concern in source and treated drinking waters of the United States
Aquatic concentrations of chemical analytes compared to ecotoxicity estimates
The importance of quality control in validating concentrationsof contaminants of emerging concern in source and treateddrinking water samples
Human health screening and public health significance of contaminants of emerging concern detected in public water supplies
Comparison of in vitro estrogenic activity and estrogen concentrations insource and treated waters from 25 U.S. drinking water treatment plants
Nationwide reconnaissance of contaminants of emerging concern in source and treated drinking waters of the United States: Pharmaceuticals
Microbial pathogens in source and treated waters from drinking water treatment plants in the United States and implications for human health
- Overview
Waterborne viruses, one of the leading causes of gastrointestinal illnesses, were measured in United States drinking water sources and finished water. Scientists used a combination of measurement and statistical techniques to overcome limitations to quantifying these viruses, thus offering an enhanced method for virus monitoring.
Bacterial and viral pathogens in drinking water have historically posed significant health risk to humans. Drinking water treatment, including filtration and disinfection, in the United States in the early 20th century is credited with dramatically reducing the incidence pathogens from incoming water to provide communities with safe drinking water. However, pathogens are still reported as one of the leading causes of gastrointestinal illnesses from drinking water ingestion.
Pathogens, including viruses, can enter drinking water sources (rivers, lakes, groundwater, and reservoirs) through runoff from urban and agricultural areas; leakage from sewers and septic systems, storm water, and sewer overflows; and treated wastewater. If the pathogens persist through treatment, they can contribute viruses to drinking water and result in human exposure.
Enteric viruses, those that can replicate in the human digestive track, are one of many pathogens that are monitored in the Nation’s drinking water. Typically, drinking water facilities estimate the removal efficiency of enteric viruses based on the presence of fecal indicator bacteria. However, fecal indicator bacteria presence is not always indicative of viral presence, given the different survival rates and transport mechanisms of bacteria and viruses.
Picture showing equipment used to collect water for analyses of viruses (Varughese and others 2019).(Credit: Eunice Varughese, U.S. Enviromental Protection Agency.) When viruses are measured in water, a technique called polymerase chain reaction (PCR) or quantitative PCR (qPCR) is used. One advantage of the qPCR method is that it can quickly generate a sufficient amount of genetic material for analysis. However, virus occurrence and concentration may be underestimated owing to its multistep viral concentration process or to PCR inhibition, where chemicals in the water sample prevent generation of sufficient amounts of genetic material for analyses. These limitations present a challenge to accurate estimation of virus concentration in public drinking water supplies.
As a result, U.S. Environmental Protection Agency (EPA) and U.S. Geological Survey (USGS) scientists collaborated and developed a unique approach to better quantify virus occurrence and concentration in drinking water as part of a larger study on contaminants in drinking water in the United States. First, they measured the occurrence of five waterborne virus groups (adenovirus, norovirus GI, norovirus GII, entero-virus, and polyomavirus) from 25 drinking water treatment facilities across the United States using qPCR methods. Measurements included paired source (rivers, lakes, reservoirs, and groundwater) and treated water samples.
The results showed that treated drinking water had fewer viruses than source waters, indicating that treatment methods used at the facilities in this study were helpful in reducing the viruses measured. However, samples from all 25 water treatment plants had false negatives (determinization that there were no viruses present when viruses were present) due to inhibition, indicating that a method accounting for inhibition is important for better estimation of virus occurrence and concentrations in environmental waters.
The scientists applied a statistical model to account for factors affecting viral detection, including the measured sample inhibition and recovery efficiency. The qPCR data were converted to count data and input into the statistical model to calculate virus concentrations. By using a statistical framework that accounted for factors affecting viral detection, this study offers an alternative approach to estimate the occurrence and concentration of viral pathogens in environmental waters used as sources of drinking water.
This research is part of a long-term approach by the USGS Environmental Health Program's Infrastructure Team to understand microbial and chemical contaminants in drinking water and potential human exposure. It was supported by the USGS Environmental Health Programs (Toxic Substances Hydrology and Contaminant Biology) and the EPA.
- Science
Related research is listed below.
Drinking Water and Wastewater Infrastructure Science Team
The team studies toxicants and pathogens in water resources from their sources, through watersheds, aquifers, and infrastructure to human and wildlife exposures. That information is used to develop decision tools that protect human and wildlife health.Per- and Polyfluoroalkyl Substances (PFASs) detected in Source Waters and Treated Public Water Supplies
This study, which measured 17 per- and polyfuoroalkyl substances (PFASs) in source and treated public water supplies from 25 drinking water facilities as part of a broader study of contaminants in drinking water across the United States, reports that PFASs were detected in all source water and public water supply samples collected. One sample exceeded the current U.S. Environmental Protection...Occurrence of Avian Influenza Virus in Groundwater—Study Provides Baseline Data and Informs Future Studies
This pilot study provided baseline data on avian influenza virus (AIV) occurrence in groundwater underlying poultry farms and documented the challenges for conducting a pathogen transport study during a disease outbreak.Study Highlights the Complexity of Chemical Mixtures in United States Streams
A new study highlights the complexity of chemical mixtures in streams and advances the understanding of wildlife and human exposure to complex chemical mixtures.Understanding Chemical and Microbial Contaminants in Public Drinking Water
Collaborative joint agency study provides nationally consistent and rigorously quality-assured datasets on a wide range of chemical and microbial contaminants present in source and treated public drinking water supplies. Tap water was not analyzed in this study.Swine Manure Application as a Source of Hepatitis E Virus and other Livestock-Related Pathogens
The presence of indicator bacteria, hepatitis E virus (HEV), and numerous bacterial pathogen genes increased following precipitation-induced runoff events in streams draining adjacent land surfaces in Iowa where swine manure was recently applied.Assessing Environmental Chemical Mixtures in United States Streams
The U.S. Geological Survey (USGS) and the U.S. Environmental Protection Agency (EPA) are collaborating on a field-based study of chemical mixture composition and environmental effects in stream waters affected by a wide range of human activities and contaminant sources. - Publications
Below are publications associated with this research.
Kolpin, D.W., Glassmeyer, S.T., and Furlong, E.T., 2017, An introduction to joint research by the USEPA and USGS on contaminants of emerging concern in source and treated drinking waters of the United States: Science of the Total Environment, v. 579, p. 1608-1609, doi:10.1016/j.scitotenv.2016.03.052.
Estimating virus occurrence using Bayesian modeling in multiple drinking water systems of the United States
Drinking water treatment plants rely on purification of contaminated source waters to provide communities with potable water. One group of possible contaminants are enteric viruses. Measurement of viral quantities in environmental water systems are often performed using polymerase chain reaction (PCR) or quantitative PCR (qPCR). However, true values may be underestimated due to challenges involvedAuthorsEunice A. Varughese, Nichole E Brinkman, Emily M Anneken, Jennifer S Cashdollar, G. Shay Fout, Edward T. Furlong, Dana W. Kolpin, Susan T. Glassmeyer, Scott P KeelyNationwide reconnaissance of contaminants of emerging concern in source and treated drinking waters of the United States
When chemical or microbial contaminants are assessed for potential effect or possible regulation in ambient and drinking waters, a critical first step is determining if the contaminants occur and if they are at concentrations that may cause human or ecological health concerns. To this end, source and treated drinking water samples from 29 drinking water treatment plants (DWTPs) were analyzed as paAuthorsSusan T. Glassmeyer, Edward T. Furlong, Dana W. Kolpin, Angela L. Batt, Robert Benson, J. Scott Boone, Octavia D. Conerly, Maura J. Donohue, Dawn N. King, Mitchell S. Kostich, Heath E. Mash, Stacy Pfaller, Kathleen M. Schenck, Jane Ellen Simmons, Eunice A. Varughese, Stephen J. Vesper, Eric N. Villegas, Vickie S. WilsonAquatic concentrations of chemical analytes compared to ecotoxicity estimates
We describe screening level estimates of potential aquatic toxicity posed by 227 chemical analytes that were measured in 25 ambient water samples collected as part of a joint USGS/USEPA drinking water plant study. Measured concentrations were compared to biological effect concentration (EC) estimates, including USEPA aquatic life criteria, effective plasma concentrations of pharmaceuticals, publisAuthorsMitchell S. Kostich, Robert W. Flick, Angela L. Batt, Heath E. Mash, J. Scott Boone, Edward T. Furlong, Dana W. Kolpin, Susan T. GlassmeyerThe importance of quality control in validating concentrationsof contaminants of emerging concern in source and treateddrinking water samples
A national-scale survey of 247 contaminants of emerging concern (CECs), including organic and inorganic chemical compounds, andmicrobial contaminants, was conducted in source and treated drinkingwater samples from 25 treatment plants across the United States.Multiplemethodswere used to determine these CECs, including six analytical methods tomeasure 174 pharmaceuticals, personal care products, andAuthorsAngela L. Batt, Edward T. Furlong, Heath E. Mash, Susan T. Glassmeyer, Dana W. KolpinHuman health screening and public health significance of contaminants of emerging concern detected in public water supplies
The source water and treated drinking water from twenty five drinking water treatment plants (DWTPs) across the United States were sampled in 2010–2012. Samples were analyzed for 247 contaminants using 15 chemical and microbiological methods. Most of these contaminants are not regulated currently either in drinking water or in discharges to ambient water by the U. S. Environmental Protection AgencAuthorsRobert Benson, Octavia D. Conerly, William Sander, Angela L. Batt, J. Scott Boone, Edward T. Furlong, Susan T. Glassmeyer, Dana W. Kolpin, Heath MashComparison of in vitro estrogenic activity and estrogen concentrations insource and treated waters from 25 U.S. drinking water treatment plants
In vitro bioassays have been successfully used to screen for estrogenic activity in wastewater and surface water, however, few have been applied to treated drinking water. Here, extracts of source and treated water samples were assayed for estrogenic activity using T47D-KBluc cells and analyzed by liquid chromatography-Fourier transform mass spectrometry (LC-FTMS) for natural and synthetic estrogeAuthorsJustin M. Conley, Nicola Evans, Heath Mash, Laura Rosenblum, Kathleen Schenck, Susan Glassmeyer, Edward T. Furlong, Dana W. Kolpin, Vickie S. WilsonNationwide reconnaissance of contaminants of emerging concern in source and treated drinking waters of the United States: Pharmaceuticals
Mobile and persistent chemicals that are present in urban wastewater, such as pharmaceuticals, may survive on-site ormunicipal wastewater treatment and post-discharge environmental processes. These pharmaceuticals have the potential to reach surface and groundwaters, essential drinking-water sources. A joint, two-phase U.S. Geological Survey-U.S. Environmental Protection Agency study examined sourAuthorsEdward T. Furlong, Angela L. Batt, Susan T. Glassmeyer, Mary C. Noriega, Dana W. Kolpin, Heath Mash, Kathleen M. SchenckMicrobial pathogens in source and treated waters from drinking water treatment plants in the United States and implications for human health
An occurrence survey was conducted on selected pathogens in source and treated drinking water collected from 25 drinking water treatment plants (DWTPs) in the United States. Water samples were analyzed for the protozoa Giardia and Cryptosporidium (EPA Method 1623); the fungi Aspergillus fumigatus, Aspergillus niger and Aspergillus terreus (quantitative PCR [qPCR]); and the bacteria Legionella pneuAuthorsDawn N. King, Maura J. Donohue, Stephen J. Vesper, Eric N. Villegas, Michael W. Ware, Megan E. Vogel, Edward Furlong, Dana W. Kolpin, Susan T. Glassmeyer, Stacy Pfaller