Haley & Aldrich
Mr. Bennett obtained his BSc in Chemistry and MSc in Geology at Western University, Ontario, Canada. Throughout his career, Mr. Bennett has led the design, testing, and implementation of innovative site-specific approaches for documenting the natural biodegradation of fuel hydrocarbons, chlorinated solvents and 1,4-dioxane. This includes securing funding and leading the development of a method for applying compound-specific isotope analysis to document the biodegradation of 1,4-dioxane (SERDP ER-2535) and performing stable isotope assessments of anthropogenic contaminants at over a dozen sites to provide a strong scientific foundation for natural attenuation.
Compound Specific Isotope Analysis for Documenting In Situ Degradation of 1,4-Dioxane
1,4-Dioxane (1,4-D) is a legacy contaminant at many groundwater sites. It has recently been shown to biodegrade under certain conditions by natural subsurface microbial communities. Compound specific isotope analysis (CSIA) is an analytical method that quantifies the ratios of different stable isotopes of the various atoms comprising a target chemical. Stable isotope ratios change during biodegradation of most chemicals, making CSIA a powerful tool for demonstrating natural biodegradation of many contaminants. CSIA has been recently adapted to low concentrations of 1,4-D (part per billion range) allowing for the application of CSIA to demonstrate natural or enhanced in situ biodegradation of 1,4-D. This presentation will discuss how diagnostic dual isotope enrichment trends for 1,4-D degradation can be used to inform on degradation processes and will review lessons learned from application of CSIA to 1,4-D from a minimum of 12 groundwater sites to concentrations lower than 1 ug/L.