Differences in pathogen indicators between proximal urban and rural karst springs, Central Kentucky, USA

Thomas M. Reed, Alan E. Fryar, Gail M. Brion, James W. Ward

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Because of their architecture, karst aquifers are susceptible to contamination by fecal-derived pathogens. Previous studies have examined the behavior of bacterial indicators such as total coliforms (TC) and fecal coliforms (FC) in karst aquifers, but simple techniques for discriminating between human and non-human inputs are still needed. This study examines concentrations of TC, FC, atypical colonies (AC, which grow on the same media as TC), male-specific coliphage virus (MSP, an indicator of human feces), and nitrate at two springs in the Inner Bluegrass region of Kentucky (USA). Blue Hole Spring primarily drains the city of Versailles, whereas spring SP-2 drains pasture. Baseflow was monitored, usually biweekly, from December 2002 to March 2004, while storm flow was monitored in September 2003 and March 2004. At each spring, bacterial concentrations were highest in storm flow and lowest in "normal" baseflow (for which 72-h antecedent precipitation was negligible). Concentrations in baseflow tended to be highest during late spring and summer and lowest during autumn and winter. FC concentrations exceeded regulatory (contact) standards in storm-flow samples. For both storm flow and baseflow, AC concentrations were greater than TC, which in turn were greater than FC. Median AC and TC concentrations were greater in baseflow at Blue Hole than at SP-2. MSP was detected in most samples from Blue Hole but never at SP-2. The AC/TC ratio was typically <15 except for normal baseflow samples at Blue Hole, which is probably impacted by leakage from sanitary sewers, as suggested by MSP and nitrate results. Mobilization of sessile bacteria appears to reduce the AC/TC ratio during storm flow. Consequently, this ratio shows promise as a screening tool to identify sewage inputs in karst groundwater basins under baseflow conditions.

Original languageEnglish
Pages (from-to)47-55
Number of pages9
JournalEnvironmental Earth Sciences
Issue number1
StatePublished - Sep 2011

Bibliographical note

Funding Information:
Acknowledgments The research described herein was funded by the UK College of Agriculture through the Senate Bill 271 program and by the Kentucky NSF-EPSCoR program. Paul and Jerry Campbell (City of Versailles) and the UK ARC provided access to the springs. Todd Aseltyne and Todd McFarland assisted with field work; Alex Fogle (Kentucky Geological Survey) and Joseph Taraba (UK Biosystems and Agricultural Engineering) provided discharge data for SP-2; and Tricia Coakley (ERTL), Bob King (ERTL), and Jim Crutchfield (UK Plant and Soil Sciences) assisted with laboratory analyses. Larry McKay and two anonymous reviewers provided constructive comments on a prior version of the manuscript.


  • Bacteria
  • Fecal indicators
  • Groundwater
  • Karst
  • Kentucky

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Water Science and Technology
  • Soil Science
  • Pollution
  • Geology
  • Earth-Surface Processes


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