The Potential of Thelypteris palustris and Asparagus sprengeri in Phytoremediation of Arsenic Contamination

Abstract

The potential of two plants, Thelypteris palustris (marsh fern) and Asparagus sprengeri (asparagus fern), for phytoremediation of arsenic contamination was evaluated. The plants were chosen for this study because of the discovery of the arsenic hyperaccumulating fern, Pteris vittata (Ma et al., 2001) and previous research indicating asparagus fern's ability to tolerate >1200 ppm soil arsenic. Objectives were (1) to assess if selected plants are arsenic hyperaccumulators; and (2) to assess changes in the species of arsenic upon accumulation in selected plants. Greenhouse hydroponic experiments arsenic treatment levels were established by adding potassium arsenate to solution. All plants were placed into the hydroponic experiments while still potted in their growth media. Marsh fern and Asparagus fern can both accumulate arsenic. Marsh fern bioaccumulation factors (>10) are in the range of known hyperaccumulator, Pteris vittata. Therefore, Thelypteris palustris is may be a good candidate for remediation of arsenic soil contamination levels of ≤500 μg/L arsenic. Total oxidation of As (III) to As (V) does not occur in asparagus fern. The asparagus fern is arsenic tolerant (bioaccumulation factors <10), but is not considered a good potential phytoremediation candidate.

KEY WORDS:

• marsh fern
• asparagus fern
• hyperaccumulation
• XANES
• synchrotron radiation
• ICP-MS

ACKNOWLEDGMENTS

This research was supported by the Louisiana's Environmental Education Research Grant. The authors gratefully thank Dr. Ravi Ravikrisha, LSU Department of Chemical Engineering, for assistance with ICP-MS analysis.