Masters Theses

Abstract

"Owing to its broad use and environmental persistence, 1,4-dioxane (dioxane) poses a notable threat to public health and is recalcitrant to traditional remedial systems. Dioxane moves readily in an aqueous environment and is an emerging contaminant in drinking water, surface water, groundwater, and wastewater. The extent of dioxane in the biosphere is also difficult to delineate, particularly in the subsurface. Phytoremediation has demonstrated the potential for dioxane groundwater remediation. Recent findings indicate that plant-microbial symbiosis may be more advantageous for limiting potential transport and transfer into plant tissues and the atmosphere. Bioaugmentation of the rhizosphere paired with soil amendments has been proposed as a sustainable approach to improve phytoremediation applications. Biochar, as a soil amendment is evaluated to attenuate chemical activity and aid microbial survival and degradation of dioxane in the rhizosphere.

This study investigated the ability of hybrid poplar trees (DN91) to work symbiotically with rhizosphere-dwelling microorganisms, Pseudonocardia dioxanivorans (CB1190), to enhance the treatment of 1,4-dioxane in bench-scale experiments. Concurrently, phytoforensic analytical methods were developed to rapidly detect dioxane in plant tissues which was also applied in a field study to delineate an existing plume. The impact of phytovolatilization, microbial degradation, and the possible sorption of 1,4-dioxane onto biochar was quantified by HS-SPME analysis of dioxane in the stems and leaves of our cuttings using GC-MS. The dioxane concentrations found in the inoculated trees were significantly lower (p < 0.05) than those in the trees with no microbial inoculation. This finding suggests that an efficient degradation pathway for the cleanup of dioxane exists in the symbiotic interactions between plants and microbes. Furthermore, the impact of biochar on stimulating microbial degradation was not significant in this study, which could be related to the physicochemical properties of the type of biochar used in this study. Overall, this study shows that plant tissue analysis can be effective for the site characterization and distribution of contaminants in the subsurface environment, as well as being a sensor of subsurface degradation"--Abstract, p. iv

Advisor(s)

Burken, Joel G.(Joel Gerard)

Committee Member(s)

Westenberg, David J.
Nam, Paul Ki-souk

Department(s)

Civil, Architectural and Environmental Engineering

Degree Name

M.S. in Environmental Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2023

Pagination

xi, 60 pages

Note about bibliography

Includes_bibliographical_references_(pages 55-59)

Rights

© 2023 Anthony Eberechukwu Oha, All Rights Reserved

Document Type

Thesis - Open Access

File Type

text

Language

English

Thesis Number

T 12256

Electronic OCLC #

1426305821

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