Aaron D Firnstahl
Aaron is a Physical Scientist 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
Filter Total Items: 20
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...
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...
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...
Authors
Joel P. Stokdyk, Susan K. Spencer, James F. Walsh, Jane R. de Lambert, Aaron Firnstahl, Anita L. 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...
Authors
David W. Owens, Randall Hunt, Aaron Firnstahl, Maureen A. Muldoon, Mark A. Borchardt
Human Bacteroides and total coliforms as indicators of recent combined sewer overflows and rain events in urban creeks
Combined sewer overflows (CSOs) are a known source of human fecal pollution and human pathogens in urban water bodies, which may present a significant public health threat. To monitor human fecal contamination in water, bacterial fecal indicator organisms (FIOs) are traditionally used. However, because FIOs are not specific to human sources and do not correlate with human pathogens...
Authors
Shannon McGinnis, Susan K. Spencer, Aaron Firnstahl, Joel P. Stokdyk, Mark A. Borchardt, David McCarthy, Heather Murphy
Quantitative microbial risk assessment for spray irrigation of dairy manure based on an empirical fate and transport model
BACKGROUND: Spray irrigation for land-applying livestock manure is increasing in the United States as farms become larger and economies of scale make manure irrigation affordable. Human health risks from exposure to zoonotic pathogens aerosolized during manure irrigation are not well understood. OBJECTIVES: We aimed to a) estimate human health risks due to aerosolized zoonotic pathogens...
Authors
Tucker R Burch, Susan K. Spencer, Joel P. Stokdyk, Burney A Kieke, Rebecca A. Larson, Aaron Firnstahl, Ana M Rule, Mark A. Borchardt
Avian influenza virus RNA in groundwater wells supplying poultry farms affected by the 2015 influenza outbreak
During the 2015 outbreak of highly pathogenic avian influenza virus (HPAI) on poultry farms in the midwestern United States, concern was raised about the potential for HPAI to contaminate groundwater. Our study objective was to evaluate the occurrence of HPAI in the groundwater supply wells on 13 outbreak-affected poultry farms in Iowa and Wisconsin. We sampled 20 wells, six waste...
Authors
Mark A. Borchardt, Susan K. Spencer, Laura E. Hubbard, Aaron Firnstahl, Joel P. Stokdyk, Dana W. Kolpin
Determining the 95% limit of detection for waterborne pathogen analyses from primary concentration to qPCR
The limit of detection (LOD) for qPCR-based analyses is not consistently defined or determined in studies on waterborne pathogens. Moreover, the LODs reported often reflect the qPCR assay alone rather than the entire sample process. Our objective was to develop an approach to determine the 95% LOD (lowest concentration at which 95% of positive samples are detected) for the entire process...
Authors
Joel P. Stokdyk, Aaron Firnstahl, Susan K. Spencer, Tucker R Burch, Mark A. Borchardt
Science and Products
Filter Total Items: 20
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...
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...
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...
Authors
Joel P. Stokdyk, Susan K. Spencer, James F. Walsh, Jane R. de Lambert, Aaron Firnstahl, Anita L. 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...
Authors
David W. Owens, Randall Hunt, Aaron Firnstahl, Maureen A. Muldoon, Mark A. Borchardt
Human Bacteroides and total coliforms as indicators of recent combined sewer overflows and rain events in urban creeks
Combined sewer overflows (CSOs) are a known source of human fecal pollution and human pathogens in urban water bodies, which may present a significant public health threat. To monitor human fecal contamination in water, bacterial fecal indicator organisms (FIOs) are traditionally used. However, because FIOs are not specific to human sources and do not correlate with human pathogens...
Authors
Shannon McGinnis, Susan K. Spencer, Aaron Firnstahl, Joel P. Stokdyk, Mark A. Borchardt, David McCarthy, Heather Murphy
Quantitative microbial risk assessment for spray irrigation of dairy manure based on an empirical fate and transport model
BACKGROUND: Spray irrigation for land-applying livestock manure is increasing in the United States as farms become larger and economies of scale make manure irrigation affordable. Human health risks from exposure to zoonotic pathogens aerosolized during manure irrigation are not well understood. OBJECTIVES: We aimed to a) estimate human health risks due to aerosolized zoonotic pathogens...
Authors
Tucker R Burch, Susan K. Spencer, Joel P. Stokdyk, Burney A Kieke, Rebecca A. Larson, Aaron Firnstahl, Ana M Rule, Mark A. Borchardt
Avian influenza virus RNA in groundwater wells supplying poultry farms affected by the 2015 influenza outbreak
During the 2015 outbreak of highly pathogenic avian influenza virus (HPAI) on poultry farms in the midwestern United States, concern was raised about the potential for HPAI to contaminate groundwater. Our study objective was to evaluate the occurrence of HPAI in the groundwater supply wells on 13 outbreak-affected poultry farms in Iowa and Wisconsin. We sampled 20 wells, six waste...
Authors
Mark A. Borchardt, Susan K. Spencer, Laura E. Hubbard, Aaron Firnstahl, Joel P. Stokdyk, Dana W. Kolpin
Determining the 95% limit of detection for waterborne pathogen analyses from primary concentration to qPCR
The limit of detection (LOD) for qPCR-based analyses is not consistently defined or determined in studies on waterborne pathogens. Moreover, the LODs reported often reflect the qPCR assay alone rather than the entire sample process. Our objective was to develop an approach to determine the 95% LOD (lowest concentration at which 95% of positive samples are detected) for the entire process...
Authors
Joel P. Stokdyk, Aaron Firnstahl, Susan K. Spencer, Tucker R Burch, Mark A. Borchardt