ARSENIC UPTAKE FROM CONTAMINATED SOILS BY A HYPERACCUMULATING FERN

Lena Ma, Cong Tu, Beth Kennelley and Ken Komar (Soil and Water Science Department, University of Florida, Gainesville, FL 32611-0290, USA)

Arsenic is of great environmental concern due to its extensive contamination and carcinogenic toxicity. There is a great need for reliable and cost-effective technologies capable of reducing arsenic in soils to environmentally acceptable levels. Phytoremediation, a plant-based green technology, has been successfully used to remove heavy metals from contaminated soils. However, no arsenic hyperaccumulating plant is currently available until recently. We have discovered an extremely efficient arsenic-hyperaccumulating fern. A number of fern samples were collected from an arsenic contaminated soil and analyzed for arsenic concentrations. In addition, ferns after growing in artificially contaminated soils for up to 8 weeks in a greenhouse were harvested and analyzed for arsenic concentrations. The highest arsenic concentrations in the aboveground biomass in ferns growing in the arsenic contaminated soil in the field was 7,500 ppm, with arsenic concentration in aboveground b!

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iomass being up to 200 times greater than those of soils. After 4 weeks, the arsenic concentration reached over 2% in the aboveground biomass of the fern growing in the soil spiked with 500 ppm arsenic. Obviously, this fern has an extraordinary capability to uptake a large quantity of arsenic from soils and translocate them to aboveground biomass. This fern has a great potential to be used for phytoremediating arsenic contaminated soils and wastes.