Identifying Biomarkers to Optimize Bioremediation Approaches for Contaminated Groundwater

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Past activities have resulted in the contamination of many groundwater aquifers with tetrachloroethene, trichloroethene, and 1,4-dioxane. These contaminants are problematic because of their risks to human health. Unfortunately, current methods to clean-up groundwater have not been successful for these pollutants. As an alternative clean-up approach, scientists have explored the use of bacteria to biodegrade these pollutants. However, little is known about the identity and abundance of these bacteria in the groundwater. Without this information, it is difficult to predict the time required for contaminant removal. The specific goals of this research are to identify bacteria responsible for 1,4-dioxane and chlorinated solvent biodegradation under conditions in the groundwater. Knowledge concerning the quantity of bacteria in groundwater will result in more effective management approaches for contaminated groundwater. The research will involve underrepresented minority undergraduates through the Michigan Louis Stokes Alliance for Minority Participation. In addition, research results will also be incorporated into activities at the High School Engineering Institute. Together, these educational outreach activities will help improve the Nation's scientific knowledge and increase diversity in STEM fields. The co-contamination of many sites with the chlorinated solvents, their metabolites and 1,4-dioxane is particularly problematic because of the risks to human health and the lack of remediation approaches to remove all chemicals concurrently. Although much research has been directed towards the remediation of the chlorinated solvents, less is known about the potential for 1,4-dioxane bioremediation. Here, the overall objective is to develop biomarkers to optimize groundwater bioremediation approaches at chlorinated solvent and 1,4-dioxane co-contaminated sites. The specific objectives are to i) determine which microorganisms are responsible for carbon uptake from 1,4-dioxane under methanogenic conditions using stable isotope probing and generate methods/data for predicting in situ removal, ii) identify biomarkers for in situ aerobic 1,4-dioxane biodegradation in groundwater, and iii) determine which biomarkers are appropriate for aerobic co-metabolic chlorinated ethene degradation. The research will include underrepresented minority undergraduates through the Michigan Louis Stokes Alliance for Minority Participation. Also, undergraduates will participate as part of the Engineering Summer Undergraduate Research Experience Program (EnSURE). EnSURE is a 10-week program involving professional development activities, mentoring of students in a research project and participation in a campus-wide symposium for research. Further, activities will include collaborative efforts in K-12 outreach programs, such as the High School Engineering Institute (offered during the summer). The project will also enhance educator development at the graduate student level. The designed biomarkers will enable the remediation community to determine if these functional genes are present at their sites and, if so, quantify their abundance and determine the predicted time for contaminant removal and site closure.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.