Date of Award

5-2021

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Chemistry and Biochemistry

Thesis Sponsor/Dissertation Chair/Project Chair

Nina Goodey

Committee Member

Lynn Schneemeyer

Committee Member

Jennifer Krumins

Abstract

The distribution of contaminants in polluted soils can vary through depth. We measured the vertical distributions of heavy metals and enzyme activities in the top 10 cm of side-by-side, vegetated and barren brownfield soils. The data showed metals significantly accumulated in the top 2 cm of barren soil and uniformly distributed through vegetated soil. When planted, germination rate was significantly lower in the previously barren soil, with the metal layer intact, compared to mixed barren soil. These data suggest a feedback loop in which plant roots redistribute metals, diluting metal-rich regions, yet germination remains initially limited by a metal cap. We conclude that not only metal concentrations but also their vertical distributions through the top 10 cm of brownfield soil impact soil health and plant success. Published studies on vertical distribution of enzyme activities and metal concentrations have treated the top 10-20 cm as a single cross-section and thus would have missed a thin (< 2 cm thick) metal cap on the surface of the soil. If metals have accumulated on the soil surface, then changing the initial environmental assessment to focus on the top 2 cm can more effectively guide efforts to convert industrial barrens to vegetated environments.

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