Phytoremediation of Arsenic-Contaminated Groundwater by the Arsenic Hyperaccumulating Fern Pteris vittata L.

ABSTRACT

Arsenic concentrations in a much larger fraction of U.S. groundwater sources will exceed the maximum contaminant limit when the new 10 μg L⁻¹ EPA standard for drinking water takes effect in 2006. Thus, it is important to develop remediation technologies that can meet this new standard. Phytoremediation of arsenic-contaminated groundwater is a relatively new idea. In this research, an arsenic-hyperaccumulating fern, commonly known as Chinese Brake fern (Pteris vittata L.), was grown hydroponically to examine its effectiveness in arsenic removal from what is believed to be herbicide-contaminated groundwater. One plant grown in 600 mL of groundwater effectively reduced the arsenic concentration from 46 to less than 10 μg L⁻¹ in 3 days. Re-used plants continued to take up arsenic from the groundwater, albeit at a slower rate (from 46 to 20 μg L^{− 1} during the same time). Young fern plants were more efficient in removing arsenic than were older fern plants of similar size. The addition of a supplement of phosphate-free Hoagland nutrition to the groundwater had little effect on arsenic removal, but the addition of phosphate nutrition significantly reduced its arsenic affinity and, thus, inhibited the arsenic removal. This study suggested that Chinese Brake has some potential to remove arsenic from groundwater.

Keywords:

• arsenic
• groundwater
• hyperaccumulation
• phytoremediation
• Chinese Brake

ACKNOWLEDGEMENT

This research was supported in part by the Florida Power & Light Company. The authors gratefully acknowledge the assistance provided by Mr. Tom Luongo in GFAAS analysis of arsenic and proofreading the manuscript.

Notes

*The initial arsenic concentration in the groundwater was 0.61 μ M or 46 μ g L^{− 1};

**Values are means of three replications. Data in the parenthesis are standard error.