Evaluation of Remediation by Community-Level Physiological Profiles

Abstract

Community-level physiological profiles (CLPP) of microbial communities based on substrate utilization have proven useful for exploring a variety of aspects of microbial ecology and may have application in the field of environmental remediation and restoration. Development of CLPP for monitoring environmental restoration is illustrated with three experimental case studies. Bioremediation of diesel fuel contaminated soils was monitored over a one year period using CLPP. CLPP of soils from contaminated and control sites showed an effect due to the presence of total petroleum hydocarbons (TPH). Treatment during the first year of the study was not effective in reducing TPH and no corresponding effect was seen in substrate profiles although a seasonal effect was noted (second year data is pending). A significant effect due to sample holding time of soils prior to analysis was seen on the CLPP of soil microbes from both contaminated and uncontaminated sites. The second field site is a fractured basalt aquifer in eastern Idaho where a contaminant plume of chlorinated solvents, sewage and radionuclides exists. CLPP on groundwater from wells with similar lithology of the screened interval reflected the presence of TCE and other pollutants with heavily contaminated wells exhibiting similar patterns that differed from uncontaminated wells. At a third site in central Idaho, aquatic bacterioplankton and periphyton communities were profiled along a stream flowpath that varied in metal concentrations due to mine drainage input. CLPP from reference sites upstream of the metal input differed from those immediately downstream of the mine drainage. Further downstream from the point source where metal concentrations declined, community profiles began to resemble the reference sites with periphyton communities recovering faster than the bacterioplankton. CLPP of indigenous microbial communities may be useful in risk assessment of contaminated sites and monitoring subsequent remedial activities.