Location: Environmentally Integrated Dairy Management Research
Project Number: 5090-12630-006-003-N
Project Type: Non-Funded Cooperative Agreement
Start Date: Jul 1, 2024
End Date: Jun 30, 2025
Objective:
Study objectives address two microbial hazards in groundwater from private wells in southwest Wisconsin: enteric pathogens that cause acute gastrointestinal illness (AGI) and antibiotic resistance genes (ARGs), which are an emerging contaminant. Specific objectives are: 1) Characterize risk of AGI from 10 viral, bacterial, and protozoan pathogens in private well water using quantitative microbial risk assessment (QMRA) and categorize AGI cases by fecal source (human wastewater and/or livestock manure) and source of groundwater (upper and lower aquifers); 2) Quantify 7 ARGs in private wells and examine co-occurrence with human and livestock fecal contamination.
Approach:
Work will be completed within the context of the recently completed Southwest Wisconsin Geology and Groundwater (SWIGG) study that included sampling and analysis of 138 private wells. Study objectives will be achieved using archived samples for additional lab work and by using new and existing data for statistical analyses and QMRA.
One hundred thirty-eight private wells were sampled from those previously positive for total coliforms or nitrate greater than 10 mg nitrate-N/L.
Risk estimates (Objective 1) will be calculated using the completed pathogen measurements and QMRA. In-hand geology data for study wells will be used to categorize risk by aquifer, and completed MST tests will be used to categorize risk by human and livestock fecal sources.
For Objective 2, archived samples will be tested for ARGs, which will be examined for co-occurrence with human and livestock fecal contamination based on the completed MST tests. Archived sample concentrates will be analyzed for 7 ARGs and intI1 using quantitative polymerase chain reaction. ARGs will include van(A), blaCTX-M, mcr1, mec(A), sul1, tet(A), and tet(W).
