Author

Maura Slocum

Date

Spring 4-29-2016

Document Type

Honors Project

First Advisor

Whipkey, Charles

Degree Name

Bachelor of Science

Major or Concentration

Environmental Science (Natural Science Concentration)

Department or Program

Earth and Environmental Sciences

Abstract

Pollution from the mining industry is a historic and global environmental issue. The remediation of resulting acid and heavy metal contamination from outdated mining practices is often costly and difficult. Contamination at mine sites can result from acid mine drainage (AMD) and the disruption of underlying geologic formations, as well as improper disposal of mine tailings and other wastes. Phytoremediation, which is the use of plants to treat soil contamination, is an emerging method of reclaiming areas contaminated by toxic heavy metals and AMD. The ecosystem of Contrary Creek, a tributary of Lake Anna in Louisa County, Virginia, has been significantly affected by AMD from abandoned pyrite mining operations. Bioavailable and total recoverable metal concentrations, pH, and organic matter content were analyzed in soil samples from sites along the creek. Soil from two sites along Contrary Creek and an uncontaminated site was collected and used to grow two known hyperaccumulator plants, a grass, Chrysopogon zizanioides, and a fern, Pteris cretica. The plants were grown in controlled conditions similar to regional environmental characteristics and harvested after 21, 80, and 170 days. The shoots, roots, and soil were analyzed for metal concentrations. These results were compared with initial Day 1 concentrations to determine the ability of Chrysopogon zizanioides and Pteris cretica to hyperaccumulate metals from these Virginia AMD-contaminated soils. The Pteris fern and Chrysopogon grass accumulated significant concentrations of aluminum, arsenic, chromium, copper, iron, manganese, and lead after 170 days of growth. The concentrations of these metals in plant biomass were significantly higher than the concentrations in the bioavailable fraction of the soil by Day 170, indicating that both plants are hyperaccumulators of the metals present in the Contrary Creek soil and could serve as phytoremdiators at Contrary Creek.

Language

English

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