Semester of Graduation

Fall 2020

Degree

Master of Science (MS)

Department

School of Plant, Environmental & Soil Sciences

Document Type

Thesis

Abstract

High lead (Pb) contamination of soils is a threat to human health. Urban area soils are frequently contaminated with lead from settling of gasoline exhaust, brake dust, and lead paint on homes, old playground equipment, etc. Exposure to soil-lead occurs by ingestion or inhalation and poses an elevated risk for young children. Indirect ingestion can occur through the food chain through activities such as growing certain vegetables with an ability to tolerate and accumulate lead in edible tissues. Many university extension systems recommend growing vegetables in raised beds as a reasonable reduced risk option for avoiding lead accumulation in garden vegetables particularly leafy greens and root vegetables. However, limited research outlines the efficacy of specific raised bed practices in excluding lead from the initially uncontaminated planting space. To address the soil-lead exposure pathway via garden produce, this study evaluates differential uptake of lead in common cool season vegetable crops and supplements gaps in the literature pertaining to raised-bed garden practices in lead contaminated areas. Three species of leafy green vegetables were grown in soil-less media contaminated at 0, 500, 1000, and 2000 ppm Pb to observe plant growth patterns and accumulation in contaminated raised bed conditions. Findings suggest minimal observations of toxic effects on growth and variable lead accumulation above threshold contaminant levels. Simulated raised beds were subsequently constructed to evaluate barriers placed at the interface between contaminated soil and the base of the uncontaminated raised bed soil. The resulting data suggests that neoprene rubber sheeting does not exclude lead from the raised bed.

Committee Chair

Kathryn Fontenot

DOI

10.31390/gradschool_theses.5243

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