Aaron is a Hydrologic Technician at the Upper Midwest Water Science Center.
Education and Certifications
B.S. 2009, Geology and Geophysics; B.S. History; Certificate, European Studies; Certificate, Classical Studies; University of Wisconsin-Madison
Science and Products
Well Water Advisory Forecasts for northeast Wisconsin
The fractured bedrock of northeast Wisconsin is vulnerable to groundwater contamination because water and contaminants can move quickly. LIDE is launching a study to predict contamination of private wells in northeast WI using Runoff Risk Advisory Forecasts (RRAF). RRAF is an online tool that forecasts conditions conducive to surface runoff, and the long-term vision is to leverage its forecasts to...
SARS-CoV-2 Data from National Wastewater Surveillance System Surge Capacity Sampling, September 2021
Wastewater-based epidemiology (WBE) is used to determine the consumption of, or exposure to, chemicals or pathogens in human populations, and is conducted by collecting representative samples of untreated wastewater (influent) to quantify pathogens shed in the population served by the sampled wastewater system. The Centers for Disease Control and Prevention (CDC) and the US Department of Health an

LIDE team members in front of field vehicle when traveling to collect private well water samples
Filter Total Items: 16
Microbial source tracking and land use associations for antibiotic resistance genes in private wells influenced by human and livestock fecal sources
Antimicrobial resistance is a growing public health problem that requires an integrated approach among human, agricultural, and environmental sectors. However, few studies address all three components simultaneously. We investigated the occurrence of five antibiotic resistance genes (ARGs) and the class 1 integron gene (intI1) in private wells drawing water from a vulnerable aquifer influenced by
Authors
Tucker R. Burch, Joel P. Stokdyk, Aaron Firnstahl, Burney Kieke Jr, Rachel Cook, Sarah Opelt, Sue Spencer, Lisa Durso, Mark A. Borchardt
Assessing private well contamination in Grant, Iowa, and Lafayette Counties, Wisconsin: The southwest Wisconsin groundwater and geology study
Rural residents of Grant, Iowa, and Lafayette Counties in Wisconsin rely on private wells for their water. Contaminants like nitrate and bacteria from septic systems, fertilizer, and manure can contaminate the groundwater that residents use. Groundwater is vulnerable to contamination where the soil layer is thin and the bedrock is fractured, which is the case for much of the study region. This stu
Authors
Joel P. Stokdyk, Mark A. Borchardt, Aaron Firnstahl, Ken Bradbury, Moe Muldoon, Burney A Kieke
Statewide quantitative microbial risk assessment for waterborne viruses, bacteria, and protozoa in public water supply wells in Minnesota
Infection risk from waterborne pathogens can be estimated via quantitative microbial risk assessment (QMRA) and forms an important consideration in the management of public groundwater systems. However, few groundwater QMRAs use site-specific hazard identification and exposure assessment, so prevailing risks in these systems remain poorly defined. We estimated the infection risk for 9 waterborne p
Authors
Tucker R. Burch, Joel P. Stokdyk, Nancy Rice, Anita C. Anderson, James F. Walsh, Sue Spencer, Aaron Firnstahl, Mark A. Borchardt
Fate and seasonality of antimicrobial resistance genes during full-scale anaerobic digestion of cattle manure across seven livestock production facilities
Anaerobic digestion has been suggested as an intervention to attenuate antibiotic resistance genes (ARGs) in livestock manure but supporting data have typically been collected at laboratory scale. Few studies have quantified ARG fate during full-scale digestion of livestock manure. We sampled untreated manure and digestate from seven full-scale mesophilic dairy manure digesters to assess ARG fate
Authors
Tucker R. Burch, Aaron Firnstahl, Susan K. Spencer, Rebecca A. Larson, Mark A. Borchardt
Sources and risk factors for nitrate and microbial contamination of private household wells in the fractured dolomite aquifer of northeastern Wisconsin
Background:Groundwater quality in the Silurian dolomite aquifer in northeastern Wisconsin, USA, has become contentious as dairy farms and exurban development expand.Objectives:We investigated private household wells in the region, determining the extent, sources, and risk factors of nitrate and microbial contamination.Methods:Total coliforms, Escherichia coli, and nitrate were evaluated by synopti
Authors
Mark A. Borchardt, Joel P. Stokdyk, Burney A Kieke, Maureen A. Muldoon, Susan K. Spencer, Aaron Firnstahl, Davina Bonness, Randall J. Hunt, Tucker R. Burch
Quantitative microbial risk assessment for contaminated private wells in the fractured dolomite aquifer of Kewaunee County, Wisconsin
Background:Private wells are an important source of drinking water in Kewaunee County, Wisconsin. Due to the region’s fractured dolomite aquifer, these wells are vulnerable to contamination by human and zoonotic gastrointestinal pathogens originating from land-applied cattle manure and private septic systems.Objective:We determined the magnitude of the health burden associated with contamination o
Authors
Tucker R. Burch, Joel P. Stokdyk, Susan K. Spencer, Burney A Kieke, Aaron Firnstahl, Maureen A. Muldoon, Mark A. Borchardt
Microbial pathogens and contaminants of emerging concern in groundwater at an urban subsurface stormwater infiltration site
Urban stormwater may contain a variety of pollutants, including viruses and other pathogens, and contaminants of emerging concern (pharmaceuticals, artificial sweeteners, and personal care products). In vulnerable geologic settings, the potential exists for these contaminants to reach underlying aquifers and contaminate drinking water wells. Viruses and other pathogens, as well as other contaminan
Authors
Jane R. de Lambert, James F. Walsh, Deanna P. Scher, Aaron Firnstahl, Mark A. Borchardt
Viral, bacterial, and protozoan pathogens and fecal markers in wells supplying groundwater to public water systems in Minnesota, USA
Drinking water supply wells can be contaminated by a broad range of waterborne pathogens. However, groundwater assessments frequently measure microbial indicators or a single pathogen type, which provides a limited characterization of potential health risk. This study assessed contamination of wells by testing for viral, bacterial, and protozoan pathogens and fecal markers. Wells supplying groundw
Authors
Joel P. Stokdyk, Aaron Firnstahl, James F. Walsh, Susan K. Spencer, Jane R. de Lambert, Anita C. Anderson, Lih-in W. Rezania, Burney A Kieke, Mark A. Borchardt
Septic systems and rainfall influence human fecal markers and indicator organisms occurrence in private wells in southeastern Pennsylvania
In the United States approximately 48 million people are served by private wells. Unlike public water systems, private well water quality is not monitored and there are few studies on the extent and sources of contamination of private wells. We extensively investigated five private wells to understand the variability in microbial contamination, the role of septic systems as sources of contaminatio
Authors
Heather Murphy, Shannon McGinnis, Ryan Blunt, Joel P. Stokdyk, Jingwei Wu, Alexander Cagle, Donna Denno, Susan K. Spencer, Aaron Firnstahl, Mark A. Borchardt
Laboratory for Infectious Disease and the Environment (LIDE)
The Laboratory for Infectious Disease and the Environment (LIDE) studies the occurrence, fate and transport, and health effects of human and agricultural zoonotic pathogens in the environment. The LIDE is an interagency collaborative effort between the U.S. Geological Survey and the U.S. Department of Agriculture-Agricultural Research Service that conducts research to inform decision makers and ad
Authors
Joel P. Stokdyk, Jennifer L. Bruce, Tucker R. Burch, Susan K. Spencer, Aaron Firnstahl, Mark A. Borchardt
Cryptosporidium incidence and surface water influence of groundwater supplying public water systems in Minnesota, USA
Regulations for public water systems (PWS) in the U.S. consider Cryptosporidium a microbial contaminant of surface water supplies. Ground- water is assumed free of Cryptosporidium unless surface water is entering supply wells. We determined the incidence of Cryptosporidium in PWS wells varying in surface water influence. Community and noncommunity PWS wells (n = 145) were sampled (n = 964) and anal
Authors
Joel P. Stokdyk, Susan K. Spencer, James F. Walsh, Jane R. de Lambert, Aaron D. Fimstahl, Anita C. Anderson, Lih-in W. Rezania, Mark A. Borchardt
Automated time-series measurement of microbial concentrations in groundwater-derived water supplies
Fecal contamination by human and animal pathogens, including viruses, bacteria, and protozoa, is a potential human health hazard, especially with regards to drinking water. Pathogen occurrence in groundwater varies considerably in space and time, which can be difficult to characterize as sampling typically requires hundreds of liters of water to be passed through a filter. Here we describe the des
Authors
David W. Owens, Randall J. Hunt, Aaron Firnstahl, Maureen A. Muldoon, Mark A. Borchardt
Science and Products
- Science
Well Water Advisory Forecasts for northeast Wisconsin
The fractured bedrock of northeast Wisconsin is vulnerable to groundwater contamination because water and contaminants can move quickly. LIDE is launching a study to predict contamination of private wells in northeast WI using Runoff Risk Advisory Forecasts (RRAF). RRAF is an online tool that forecasts conditions conducive to surface runoff, and the long-term vision is to leverage its forecasts to... - Data
SARS-CoV-2 Data from National Wastewater Surveillance System Surge Capacity Sampling, September 2021
Wastewater-based epidemiology (WBE) is used to determine the consumption of, or exposure to, chemicals or pathogens in human populations, and is conducted by collecting representative samples of untreated wastewater (influent) to quantify pathogens shed in the population served by the sampled wastewater system. The Centers for Disease Control and Prevention (CDC) and the US Department of Health an - Multimedia
LIDE team members in front of field vehicle when traveling to collect private well water samples
- Publications
Filter Total Items: 16
Microbial source tracking and land use associations for antibiotic resistance genes in private wells influenced by human and livestock fecal sources
Antimicrobial resistance is a growing public health problem that requires an integrated approach among human, agricultural, and environmental sectors. However, few studies address all three components simultaneously. We investigated the occurrence of five antibiotic resistance genes (ARGs) and the class 1 integron gene (intI1) in private wells drawing water from a vulnerable aquifer influenced byAuthorsTucker R. Burch, Joel P. Stokdyk, Aaron Firnstahl, Burney Kieke Jr, Rachel Cook, Sarah Opelt, Sue Spencer, Lisa Durso, Mark A. BorchardtAssessing private well contamination in Grant, Iowa, and Lafayette Counties, Wisconsin: The southwest Wisconsin groundwater and geology study
Rural residents of Grant, Iowa, and Lafayette Counties in Wisconsin rely on private wells for their water. Contaminants like nitrate and bacteria from septic systems, fertilizer, and manure can contaminate the groundwater that residents use. Groundwater is vulnerable to contamination where the soil layer is thin and the bedrock is fractured, which is the case for much of the study region. This stuAuthorsJoel P. Stokdyk, Mark A. Borchardt, Aaron Firnstahl, Ken Bradbury, Moe Muldoon, Burney A KiekeStatewide quantitative microbial risk assessment for waterborne viruses, bacteria, and protozoa in public water supply wells in Minnesota
Infection risk from waterborne pathogens can be estimated via quantitative microbial risk assessment (QMRA) and forms an important consideration in the management of public groundwater systems. However, few groundwater QMRAs use site-specific hazard identification and exposure assessment, so prevailing risks in these systems remain poorly defined. We estimated the infection risk for 9 waterborne pAuthorsTucker R. Burch, Joel P. Stokdyk, Nancy Rice, Anita C. Anderson, James F. Walsh, Sue Spencer, Aaron Firnstahl, Mark A. BorchardtFate and seasonality of antimicrobial resistance genes during full-scale anaerobic digestion of cattle manure across seven livestock production facilities
Anaerobic digestion has been suggested as an intervention to attenuate antibiotic resistance genes (ARGs) in livestock manure but supporting data have typically been collected at laboratory scale. Few studies have quantified ARG fate during full-scale digestion of livestock manure. We sampled untreated manure and digestate from seven full-scale mesophilic dairy manure digesters to assess ARG fateAuthorsTucker R. Burch, Aaron Firnstahl, Susan K. Spencer, Rebecca A. Larson, Mark A. BorchardtSources and risk factors for nitrate and microbial contamination of private household wells in the fractured dolomite aquifer of northeastern Wisconsin
Background:Groundwater quality in the Silurian dolomite aquifer in northeastern Wisconsin, USA, has become contentious as dairy farms and exurban development expand.Objectives:We investigated private household wells in the region, determining the extent, sources, and risk factors of nitrate and microbial contamination.Methods:Total coliforms, Escherichia coli, and nitrate were evaluated by synoptiAuthorsMark A. Borchardt, Joel P. Stokdyk, Burney A Kieke, Maureen A. Muldoon, Susan K. Spencer, Aaron Firnstahl, Davina Bonness, Randall J. Hunt, Tucker R. BurchQuantitative microbial risk assessment for contaminated private wells in the fractured dolomite aquifer of Kewaunee County, Wisconsin
Background:Private wells are an important source of drinking water in Kewaunee County, Wisconsin. Due to the region’s fractured dolomite aquifer, these wells are vulnerable to contamination by human and zoonotic gastrointestinal pathogens originating from land-applied cattle manure and private septic systems.Objective:We determined the magnitude of the health burden associated with contamination oAuthorsTucker R. Burch, Joel P. Stokdyk, Susan K. Spencer, Burney A Kieke, Aaron Firnstahl, Maureen A. Muldoon, Mark A. BorchardtMicrobial pathogens and contaminants of emerging concern in groundwater at an urban subsurface stormwater infiltration site
Urban stormwater may contain a variety of pollutants, including viruses and other pathogens, and contaminants of emerging concern (pharmaceuticals, artificial sweeteners, and personal care products). In vulnerable geologic settings, the potential exists for these contaminants to reach underlying aquifers and contaminate drinking water wells. Viruses and other pathogens, as well as other contaminanAuthorsJane R. de Lambert, James F. Walsh, Deanna P. Scher, Aaron Firnstahl, Mark A. BorchardtViral, bacterial, and protozoan pathogens and fecal markers in wells supplying groundwater to public water systems in Minnesota, USA
Drinking water supply wells can be contaminated by a broad range of waterborne pathogens. However, groundwater assessments frequently measure microbial indicators or a single pathogen type, which provides a limited characterization of potential health risk. This study assessed contamination of wells by testing for viral, bacterial, and protozoan pathogens and fecal markers. Wells supplying groundwAuthorsJoel P. Stokdyk, Aaron Firnstahl, James F. Walsh, Susan K. Spencer, Jane R. de Lambert, Anita C. Anderson, Lih-in W. Rezania, Burney A Kieke, Mark A. BorchardtSeptic systems and rainfall influence human fecal markers and indicator organisms occurrence in private wells in southeastern Pennsylvania
In the United States approximately 48 million people are served by private wells. Unlike public water systems, private well water quality is not monitored and there are few studies on the extent and sources of contamination of private wells. We extensively investigated five private wells to understand the variability in microbial contamination, the role of septic systems as sources of contaminatioAuthorsHeather Murphy, Shannon McGinnis, Ryan Blunt, Joel P. Stokdyk, Jingwei Wu, Alexander Cagle, Donna Denno, Susan K. Spencer, Aaron Firnstahl, Mark A. BorchardtLaboratory for Infectious Disease and the Environment (LIDE)
The Laboratory for Infectious Disease and the Environment (LIDE) studies the occurrence, fate and transport, and health effects of human and agricultural zoonotic pathogens in the environment. The LIDE is an interagency collaborative effort between the U.S. Geological Survey and the U.S. Department of Agriculture-Agricultural Research Service that conducts research to inform decision makers and adAuthorsJoel P. Stokdyk, Jennifer L. Bruce, Tucker R. Burch, Susan K. Spencer, Aaron Firnstahl, Mark A. BorchardtCryptosporidium incidence and surface water influence of groundwater supplying public water systems in Minnesota, USA
Regulations for public water systems (PWS) in the U.S. consider Cryptosporidium a microbial contaminant of surface water supplies. Ground- water is assumed free of Cryptosporidium unless surface water is entering supply wells. We determined the incidence of Cryptosporidium in PWS wells varying in surface water influence. Community and noncommunity PWS wells (n = 145) were sampled (n = 964) and analAuthorsJoel P. Stokdyk, Susan K. Spencer, James F. Walsh, Jane R. de Lambert, Aaron D. Fimstahl, Anita C. Anderson, Lih-in W. Rezania, Mark A. BorchardtAutomated time-series measurement of microbial concentrations in groundwater-derived water supplies
Fecal contamination by human and animal pathogens, including viruses, bacteria, and protozoa, is a potential human health hazard, especially with regards to drinking water. Pathogen occurrence in groundwater varies considerably in space and time, which can be difficult to characterize as sampling typically requires hundreds of liters of water to be passed through a filter. Here we describe the desAuthorsDavid W. Owens, Randall J. Hunt, Aaron Firnstahl, Maureen A. Muldoon, Mark A. Borchardt - News