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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Environmentally Integrated Dairy Management Research » Research » Publications at this Location » Publication #411061

Research Project: Managing Nutrients and Assessing Pathogen Emission Risks for Sustainable Dairy Production Systems

Location: Environmentally Integrated Dairy Management Research

Title: Fecal source tracking for antibiotic resistance genes in private wells in southwest Wisconsin

item STOKDYK, JOEL - Us Geological Survey (USGS)
item Opelt, Sarah
item FIRNSTAHL, AARON - Us Geological Survey (USGS)
item Cook, Rachel
item Heffron, Joseph
item Burch, Tucker

Submitted to: American Water Resources Association Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/21/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Antimicrobial resistance poses a significant public health problem, with 2.8 million drug resistant infections annually in the United States. Groundwater is a reservoir of antibiotic resistance genes (ARGs), which originate in human wastewater and livestock manure. However, the relative contribution of livestock and human feces to ARG contamination of water is unknown because few studies consider multiple fecal sources simultaneously. We examined ARG occurrence for private wells in southwest Wisconsin where groundwater is influenced by septic systems, cow manure, and pig manure, which are potential sources of ARGs. Samples collected across 4 seasons were tested for 13 ARGs and 17 microbial source tracking markers for wastewater and livestock manure. Private wells (n = 138) were contaminated by human wastewater (64 wells), cow manure (33 wells), and pig manure (13 wells). Of 138 wells, 120 were positive for at least one ARG, and 66% of ARG detections co-occurred with human wastewater or livestock manure. The likelihood of detecting individual ARGs differed by fecal source, with detection of some ARGs more likely with wastewater than manure and vice versa. Total ARG detections associated with wastewater was greater than manure, consistent with the greater frequency of wastewater-positive wells. Examining ARGs where multiple fecal sources influence wells allows a novel assessment of the relative contributions of manure and septic systems to ARG occurrence in groundwater.