Comparison of Potential Bioavailable Organic Carbon and Microbial Characterization of Two Carbon Amended Sites

Abstract

Enhanced Reductive Bioremediation (ERB) is a sustainable remediation technology for the in situ treatment of chlorinated solvent contamination in aquifers. However, monitoring efforts employed to measure performance metrics rely on inferences of the subsurface environment from water samples collected at monitoring wells, ignoring the microbial activity that occurs at the granular level of aquifer sediment. This study compared potential bioavailable organic carbon (PBOC) and microbial diversity of two ERB sites. A two-sample t-test and a one-way ANOVA test with Tukey's HSD were performed to show differences between ERB and non-ERB samples and their degree of variability at selected geospatial locations downgradient of ERB treatment. Non-parametric multidimensional scaling (MDS) with similarity analysis was performed along with other data visualization plots to show microbial diversity. At Tinker AFB, results from the t-test showed that the PBOC concentrations from the ERB samples were statistically significantly greater than the samples without treatment (95% confidence; p-value = 0.018). For Dover AFB, results from the ANOVA with Tukey's HSD showed that there is a significant difference between the sample (DV3) collected in the ERB treatment zone to all other samples upgradient and downgradient of the ERB treatment. MDS and similarity analysis performed on relative abundance results from the Illumina MiSeq Sequencing of 16S rRNA genes showed large similarities among the samples within each site and the only observed differences occurred when comparing any sample to DV3, nearest to treatment.