Date of Award

Fall 12-12-2020

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Dr. Samuel Mutiti

Second Advisor

Dr. Christine Mutiti

Third Advisor

Dr. Al Mead

Abstract

This study examined the uptake of heavy metals by Moringa oleifera trees in both field and laboratory settings. The main goal of this study was to determine whether using Moringa, grown in heavily contaminated areas, as food or herbal supplements increases the risk of heavy metal exposure. The field component of this study was carried out in the Southern part of Kabwe, Zambia where a lead-zinc mine has left a legacy of severe environmental pollution in the neighboring areas. Moringa trees have several medicinal properties which is one of the reasons they were first introduced to the area. The trees were planted in this part of Kabwe to aid in remediation and so that residents could use them to counter the harmful effects of lead exposure. However, since the trees can potentially hyperaccumulate heavy metals in their shoots, residents consuming them for medicinal purposes could be unknowingly exposing themselves to toxic metals. The secondary goal of this study was to investigate the potential of Moringa to perform phytoremediation. Plant and soil samples were collected from 60 locations in the Mine Neighborhood, which is heavily polluted. Heavy metal concentrations in the plant samples were quantified using X-Ray Fluorescence (XRF) while soil samples were analyzed using Atomic Absorption Spectroscopy (AAS). In the greenhouse experiments, Moringa plants were grown using two experimental designs. The first group included plants grown for 15.5 weeks while the second had plants that were grown for 7 weeks. Plants were spiked with a 10, 000 ppm lead-nitrate solution. Mycorrhizae were added to some treatments to determine its impact on metal uptake. The plants and soil samples were quantified using XRF. The results from both the lab and field showed that Moringa grown in contaminated soils can only be consumed in quantities of less than a gram per day without risk and can be used for phytostabilization.

Available for download on Saturday, November 11, 2023

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