A U.S. Geological Survey (USGS) study elucidates the influence of animal type and environmental variables on bacterial pathogen occurrence in streams under typical watershed conditions.

In the United States, pathogens are a commonly reported stream impairment; however, pathogen impairment is assessed not by evaluating actual pathogens but by determining whether the concentration of fecal indicator bacteria (FIB) is acceptable with regard to applicable water standards. Although FIB provide a simple and inexpensive test, they do not indicate the source of pollution, have no specific relationship to pathogens, and unless epidemiological studies are performed, do not indicate health risk.
What They Did
Scientists measured pathogenic genes (shiga-toxin producing and enterotoxigenic Escherichia coli (E. coli), Salmonella, Campylobacter, and pathogenic and vancomycin-resistant enterococci) and fecal indicators (FIB, cholesterol, coprostanol, and hormones) in manure, stream water, and stream sediment samples to understand the occurrence, fate, transport, survival, and environmental sources of pathogens in 19 small watersheds in 12 U.S. States with either no major animal agriculture, or predominantly beef, dairy, swine, or poultry.
What They Determined
Scientists determined that the number and type of pathogenic genes differed among animal types and in stream water influenced by those wastes. The number of pathogen genes in manure was largest in, in descending order, dairy, beef, swine, and poultry. Stream water samples were influenced most by animal type, by local factors such as whether animals had stream access, and by the occurrence and degree of rainfall events. The occurrence of pathogen genes observed in this study is within the ranges of other watershed studies and indicates that pathogens are not typically ubiquitous in stream water or streambed sediment; however, many genes were from viable organisms, including several (shiga-toxin producing or enterotoxigenic E. coli, Salmonella, and vancomycin-resistant enterococci) that could potentially affect either human or animal health. There was no association between the total number of pathogen genes and any fecal indicator in samples collected during dry conditions; however, for samples collected post-rainfall, the number of pathogen genes detected was significantly correlated with cholesterol, coprostanol, and marginally with some FIB concentrations.
Environmental Health Considerations
This study provides specific data on pathogenic genes associated with animal types and insights into the influence of animal agriculture on stream water quality. The results indicate that pathogen gene profiles offer the potential to address both the source of and the human and ecological risks associated with fecal pollution. The inclusion of animal-specific genes, indicating the presence of pathogens, adds to the body of knowledge by providing information on potential health risks.
This research was funded by the USGS Ecosystems Mission Area’s Environmental Health Program (Contaminant Biology and Toxic Substances Hydrology).
Below are other science projects associated with this project.
Food Resources Lifecycle Integrated Science Team
Bacteriological Research — Lansing, Michigan
New Study Measures Crop Bactericide, Nitrapyrin, in Iowa Streams
Swine Manure Application as a Source of Hepatitis E Virus and other Livestock-Related Pathogens
Distinct Microbiomes Identified in Landfills Throughout the United States
Iodinated Disinfection Byproducts found in Dairy-Impacted Wastewaters and Streams
Contaminants of Emerging Concern in the Environment
Potential Exposure to Bacteria and Viruses Weeks after Swine Manure Spill
Biosolids, Animal Manure, and Earthworms: Is There a Connection?
Below are publications associated with this project.
Contamination with bacterial zoonotic pathogen genes in U.S. streams influenced by varying types of animal agriculture
- Overview
A U.S. Geological Survey (USGS) study elucidates the influence of animal type and environmental variables on bacterial pathogen occurrence in streams under typical watershed conditions.
Sources/Usage: Some content may have restrictions. Visit Media to see details.The team of USGS scientists collected stream water samples before and after rainfall events for this study. In this photo a USGS scientist is taking measurements of field parameters (dissolved oxygen, water temperature, specific conductance, and pH) from New York Branch, Iowa, at low flow (baseflow) conditions. Photo Credit: Dana W. Kolpin, USGS. In the United States, pathogens are a commonly reported stream impairment; however, pathogen impairment is assessed not by evaluating actual pathogens but by determining whether the concentration of fecal indicator bacteria (FIB) is acceptable with regard to applicable water standards. Although FIB provide a simple and inexpensive test, they do not indicate the source of pollution, have no specific relationship to pathogens, and unless epidemiological studies are performed, do not indicate health risk.
What They Did
Scientists measured pathogenic genes (shiga-toxin producing and enterotoxigenic Escherichia coli (E. coli), Salmonella, Campylobacter, and pathogenic and vancomycin-resistant enterococci) and fecal indicators (FIB, cholesterol, coprostanol, and hormones) in manure, stream water, and stream sediment samples to understand the occurrence, fate, transport, survival, and environmental sources of pathogens in 19 small watersheds in 12 U.S. States with either no major animal agriculture, or predominantly beef, dairy, swine, or poultry.
What They Determined
Scientists determined that the number and type of pathogenic genes differed among animal types and in stream water influenced by those wastes. The number of pathogen genes in manure was largest in, in descending order, dairy, beef, swine, and poultry. Stream water samples were influenced most by animal type, by local factors such as whether animals had stream access, and by the occurrence and degree of rainfall events. The occurrence of pathogen genes observed in this study is within the ranges of other watershed studies and indicates that pathogens are not typically ubiquitous in stream water or streambed sediment; however, many genes were from viable organisms, including several (shiga-toxin producing or enterotoxigenic E. coli, Salmonella, and vancomycin-resistant enterococci) that could potentially affect either human or animal health. There was no association between the total number of pathogen genes and any fecal indicator in samples collected during dry conditions; however, for samples collected post-rainfall, the number of pathogen genes detected was significantly correlated with cholesterol, coprostanol, and marginally with some FIB concentrations.
In this photo the USGS scientist is getting ready to measure discharge (flow) in the same stream as above (from New York Branch, Iowa), but after a rainfall event. Photo Credit: Dana W. Kolpin, USGS. Environmental Health Considerations
This study provides specific data on pathogenic genes associated with animal types and insights into the influence of animal agriculture on stream water quality. The results indicate that pathogen gene profiles offer the potential to address both the source of and the human and ecological risks associated with fecal pollution. The inclusion of animal-specific genes, indicating the presence of pathogens, adds to the body of knowledge by providing information on potential health risks.
This research was funded by the USGS Ecosystems Mission Area’s Environmental Health Program (Contaminant Biology and Toxic Substances Hydrology).
- Science
Below are other science projects associated with this project.
Food Resources Lifecycle Integrated Science Team
The team studies the movement of toxicants and pathogens that could originate from the growing, raising, and processing/manufacturing of plant and animal products through the environment where exposure can occur. This information is used to understand if there are adverse effects upon exposure and to develop decision tools to protect health.Bacteriological Research — Lansing, Michigan
About the ResearchThe Environmental Health Program collaborates with microbiologists at the Michigan Bacteriological Research Laboratory (MI-BaRL). A wide array of traditional and modern molecular approaches are used to evaluate microbial pathogens and antimicrobial resistance pathways in the environment. The scientists use these approaches to advance the understanding of how environmental...New Study Measures Crop Bactericide, Nitrapyrin, in Iowa Streams
First-ever reconnaissance study documents the off-field transport of nitrapyrin — a nitrification inhibitor applied with fertilizers as a bactericide to kill natural soil bacteria for the purpose of increasing crop yields — to adjacent streams. This study is the first step in understanding the transport, occurrence, and potential effects of nitrapyrin or similar compounds on nitrogen processing in...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.Distinct Microbiomes Identified in Landfills Throughout the United States
A comprehensive study by U.S. Geological Survey (USGS) and scientists from the University of Oklahoma finds distinct microbial assemblages (microbiomes) in landfill leachate across the United States and investigates factors related to microbiome formation.Iodinated Disinfection Byproducts found in Dairy-Impacted Wastewaters and Streams
Iodinated disinfection byproducts were found at stream locations downstream from treated discharge from wastewater treatment plants that receive dairy waste and in the wastewaters directly from dairy facilities.Contaminants of Emerging Concern in the Environment
The USGS is conducting source-to-receptor research on a broad range of chemical and microbial contaminants including pharmaceuticals, personal care products, pathogens, antibiotic resistant genes, and natural toxins that are not commonly considered in environmental research but have the potential to impact environmental health.Potential Exposure to Bacteria and Viruses Weeks after Swine Manure Spill
Manure spills may be an underappreciated pathway for livestock-derived contaminants to enter streams. Scientists from the U.S. Geological Survey (USGS) and Johns Hopkins Bloomberg School of Public Health studied an Iowa stream after the release of a large volume of swine manure (a manure spill). The scientists observed an increase in viruses and bacteria, which have the potential to cause human or...Biosolids, Animal Manure, and Earthworms: Is There a Connection?
Animal manure and biosolids, the solid byproduct of wastewater treatment, often are applied to agricultural crops to provide nutrients for plant growth and to improve the quality of soil. Earthworms studied in agricultural fields where manure and biosolids were applied have been found to contain organic chemicals from household products and manure. Earthworms continuously ingest soils and may... - Publications
Below are publications associated with this project.
Contamination with bacterial zoonotic pathogen genes in U.S. streams influenced by varying types of animal agriculture
Animal waste, stream water, and streambed sediment from 19 small (