Bioremediation Potential in Karst Aquifers of Tennessee and Kentucky

The carbonate aquifers of central Tennessee and Kentucky are vulnerable to dissolved and non-aqueous phase contamination due to contaminant transport through sinkholes, fractures, and other karst features. The complexity of local karst hydrology often prevents the efficient removal of contaminants through the use of traditional pump-and-treat methods. Bioremediation, in some instances, is a viable remediation option, with suitable hydrological, geochemical, and microbial site conditions. Tracer studies are essential for characterizing site hydrology and estimating residence times. Sample collection and evaluation of the geochemical conditions and existing bacterial types are critical as part of the site evaluation. Supplements have been used to stimulate specific microbial populations and foster geochemical conditions which enhance or stimulate degradation or immobilization of the contaminants in a karst aquifer. Bacteria indigenous to Tennessee and Kentucky karst systems are well adapted to a variety of metabolic capabilities and aquifer conditions. Non-traditional groundwater models that incorporate residence time distribution and decay rates are useful tools in the remediation decision-making process.