Analysis of the Phytoremediation Potential of a Chrysopogon Grass and Pteris Fern in Virginia Soils Affected By Acid Mine Drainage.

Remediation of resulting acid mine drainage (AMD) and heavy metal contamination from abandoned mines and outdated mining practices is often costly and difficult. Phytoremediation, which is the use of plants to treat soil contamination, is an evolving method to reclaim 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 significantly bioaccumulating several metals present in the soil and could serve as phytoremediators even in very acidic soils such as at Contrary Creek.