Animal waste associated with the production of livestock (poultry, cattle and swine) contributes significantly to non-point source contamination of surface water and groundwater.by nutrients and bacteria. Water-quality data collected over storm hydrographs from several springs throughout the mantled karst aquifer in northwest Arkansas indicate that concentrations of fecal coliform bacteria, dominated by Escherichia coli (E. coli), rise significantly in the early portion of the storm hydrograph. Pork bacterial concentrations occur coincident with the peak in spring discharge. Bacteria and other pathogens may survive for extended periods within the open flow domain of mantled karst aquifers. However, the transport mechanism and specific storage reservoir for the bacteria within these mantled karst environments are poorly understood but critical to the development of effective management strategies to protect human health.

This project is a multiple tracer experiment with a main goal of elucidating the fate (transport and storage) of bacteria within well-characterized, well-defined mantled karst basins. Specific questions addressed by this project include (1) the use of Eu-labeled bacteria and La-labeled clay, a visible technique to monitor injected tracer's breakthrough over time periods that include significant recharge events, and (2) what information we can infer about the bacterial fate in the subsurface from the breakthrough curves.

Multiple tracers will be injected into a losing stream segment previously used during the pilot project at the Savoy Experimental Watershed (SEW) to provide more detailed breakthrough data needed to assess the project hypotheses, and to quantify tracer loads and capture. The SEW is a University of Arkansas property of approximately 1,250 hectares. Inputs and outputs in the mantled karst aquifer formed in the Mississippian Boone and St. Joe Formations are routinely monitored at SEW, and karst basin boundaries have been previously delineated. A second well-characterized injection site in northwest Arkansas will be used to assess the exportability of the methods.

This project provides (1) minimum detection levels for the analytes injected, (2) estimated dilution factors for the tracers, (3) development of breakthrough curves to assess differences in tracer response, (4) verification of the presence of Eu-tag on variable injected bacteria at the sampling point, and (5) correlation of tracer loads to the hydrograph. If the environment in the springs is stable and conducive to the survival of fecal coliform bacteria, then it may also be conducive to supporting other potentially harmful pathogens. Results of this project will be beneficial for development of effective management strategies to minimize bacterial pathogen input into karst aquifers.

Agency
National Science Foundation (NSF)
Institute
Division of Earth Sciences (EAR)
Type
Standard Grant (Standard)
Application #
0207793
Program Officer
L. Douglas James
Project Start
Project End
Budget Start
2002-08-01
Budget End
2006-07-31
Support Year
Fiscal Year
2002
Total Cost
$274,000
Indirect Cost
Name
University of Arkansas at Fayetteville
Department
Type
DUNS #
City
Fayetteville
State
AR
Country
United States
Zip Code
72701