Phytoremediation Potential of Pityrogramma Calomelanos Var. Austroamericana and Pteris Vittata L. At a Highly Variable Arsenic Contaminated Site.

In this study, the phytoextraction potential of Pityrogramma calomelanos var. austroamericana (gold dust fern) was compared with the well-known arsenic (As) hyperaccumulator, Pteris vittata L. (Chinese brake fern) at a disused cattle dip site in northern New South Wales, Australia. Geostatistical analysis showed that the concentrations of total (at 0–20 cm depth) and phosphate-extractable (at 0–20, 20–40 and 40–60 cm depths) As were spatially variable at the site and this extreme variability (< 1 m) was also evident in the spatial maps of As. Gold dust fern produced greater frond dry biomass (mean=130 g/plant; n=40) than Chinese brake fern (mean=81 g/plant; n=40) after 10 months of growth. Arsenic concentration and uptake in fronds were also significantly (p < 0.001–0.05) higher in gold dust fern (mean=887 mg/kg and 124 mg/plant) than in Chinese brake fern (mean=674 mg/kg and 57 mg/plant). The results from this study demonstrated that gold dust fern, a species well adapted to the Australian environment, performed better than Chinese brake fern under the field conditions at the site. From our data, we predict that gold dust fern would take approximately 100 years to reduce the total soil As (at 0–60 cm depth) to 20 mg kg^–1 at the site compared to ≥ 200 years estimated for Chinese brake fern. However, long-term data are required to confirm these observations under field conditions.