Date of Graduation

Summer 2026

Degree

Master of Science in Biology

Department

Biology

Committee Chair

La Toya Kissoon-Charles

Abstract

After over 100 years of Zn and Pb mining in the Tri-State mining district (TSMD), former mines continue to be sources of metals. Metal contaminated soils can be remediated using plant-microbe interactions. Plants manipulate their microbiome and recruit microbes to increase metal tolerance. Remediating bacteria are site-specific and identifying native microbes can accelerate remediation efforts. Studies relating microbes and metal concentrations in remediated areas in the TSMD are scarce. I collected root and bulk zone soils associated with Andropogon virginicus from remediated and non-remediated sites in Webb City, MO. I used 16S rRNA gene amplicon sequencing to evaluate the bacterial community and ICP-MS to measure metal concentrations. I aimed to (1) assess metal concentrations and bacterial community composition between sites, (2) determine how bacterial diversity and relative abundance differed between root and bulk zone soils, and (3) identify relationships between metal concentrations and bacterial community composition. Metal concentrations and bacterial community composition differed between sites, but not soil parts. Zn and Cd concentrations of the remediated sites were lower than the non-remediated site but higher than the reference site. Pb concentrations of the remediated sites were lower than the non-remediated site, but similar to the reference site. Differences in metal concentrations are likely due to differences in metal mobility. Redundancy Analysis (RDA) showed that metal concentrations and soil characteristics influenced the bacterial community composition. Metal tolerant bacteria with potential for metal remediation occurred in all sites. Associations with these bacteria might contribute to A. virginicus’ ability to grow in high metal concentrations. These findings indicate that current techniques are successful, but have room for improvement, and provide insight for future endeavors.

Keywords

Tri-State Mining District (TSMD), Southwest Missouri, bacteria relative abundance, metals, bioremediation, zinc, lead, cadmium, mining

Subject Categories

Biology | Environmental Microbiology and Microbial Ecology | Environmental Monitoring | Soil Science

Copyright

© Ophelia R. Pettington

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