Irrigation of Three Wetland Species and a Hyperaccumlating Fern with Arsenic-Laden Solutions: Observations of Growth, Arsenic Uptake, Nutrient Status, and Chlorophyll Content

Abstract

Engineered wetlands can be an integral part of a treatment strategy for remediating arsenic-contaminated wastewater, wherein, As is removed by adsorption to soil particles, chemical transformation, precipitation, or accumulation by plants. The remediation process could be optimized by choosing plant species that take up As throughout the seasonal growing period. This report details experiments that utilize wetland plant species native to Ohio (Carex stricta, Pycnanthemum virginianum, and Spartina pectinata) that exhibit seasonally related maximal growth rates, plus one hyperaccumulating fern (Pteris vittata) that was used to compare arsenic tolerance. All plants were irrigated with control or As-laden nutrient solutions (either 0, 1.5, or 25 mg As L⁻¹) for 52 d. Biomass, nutrient content, and chlorophyll content were compared between plants treated and control plants (n = 5). At the higher concentration of arsenic (25 mg L⁻¹), plant biomass, leaf area, and total chlorophyll were all lower than values in control plants. A tolerance index, based on total plant biomass at the end of the experiment, indicated C. stricta (0.99) and S. pectinata (0.84) were more tolerant than the other plant species when irrigated with 1.5 mg As L⁻¹. These plant species can be considered as candidates for engineered wetlands.

KEY WORDS:

• engineered wetlands
• tolerance
• native plants

ACKNOWLEDGMENTS

We would like to acknowledge the U.S. Department of Agriculture (Grant No. 2005–38894–02307) for funding; Deanna Bobak for laboratory and administrative assistance; Jonathan Frantz, Kris Barnswell, Steven Choc, and Matthew Gorr for suggestions during preparation of the manuscript; and Doug Sturtz for operating the ICP-OES.