Use of molecular markers to compare Escherichia coli transport with traditional groundwater tracers in epikarst

Ashley Bandy, Kimberly Cook, Alan E. Fryar, Jason Polk

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Bacterial contamination of karst aquifers is a global concern as water quality deteriorates in the face of decreasing water security. Traditional abiotic groundwater tracers, which do not exhibit surface properties similar to bacteria, may not be good proxies for risk assessment of bacterial transport in karst environments. This study examined the transport and attenuation of two isolates of Escherichia coli in relation to traditional groundwater tracers (rhodamine WT dye and 1-mm-diam. latex microspheres) through ~30 m of epikarst in western Kentucky. Differential movement of the four tracers was observed, with tracer behavior dependent on flow conditions. Dye arrived at the sampling site prior to particulates. Molecular biology techniques successfully detected bacteria in the cave and showed attenuation was greater for a bacterial isolate with high attachment efficiency compared with an isolate known to have low attachment efficiency. Microspheres were first detected simultaneously with the low-attachment isolate but attained maximum concentrations during increases in discharge > 11 d post-injection. Bacteria were remobilized by storm events > 60 d after injection, illustrating the storage capacity of epikarst with regard to potential contaminants. The two bacterial strains were not transported at the same rate within the epikarst, showing breakthroughs during differing storm events and illustrating the importance of cell surface chemistry in the prediction of microorganism movement. Moreover, this study has shown that molecular analysis can be successfully used to target, quantify, and track introduced microbial tracers in karst terrains.

Original languageEnglish
Pages (from-to)88-95
Number of pages8
JournalJournal of Environmental Quality
Issue number1
StatePublished - Jan 1 2018

Bibliographical note

Publisher Copyright:
© American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. 5585 Guilford Rd., Madison, WI 53711 USA.

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Management, Monitoring, Policy and Law


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