Simultaneous phytoremediation of arsenic and heavy metals in contaminated soils with Athyrium yokoscense

摘要

Athyrium yokoscense, a fern which grows vigorously in old mining areas in Japan, accumulates Cd and Pb. However, no information is available on arsenic (As) accumulation by A. yokoscense. In this study, the effects of different concentrations of arsenite (As (Ⅲ)) or arsenate (As (Ⅴ)) on the growth and uptake of As and several heavy metals were examined. Young fems were grown in a medium composed of As-spiked soil and bark compost (2:1) in a greenhouse for 6 months. A. yokoscense was highly tolerant of As (Ⅴ) and survived on the medium containing soil spiked with 500 mg kg~(-1) of As(Ⅴ). Growth of the fern in 100 mg kg~(-1) As (Ⅴ)-spiked soil exceeded the controls without As, resulting in the highest biomass (1.95 g plant~(-1)). However, As was accumulated most efficiently in fern fronds (922 mg kg~(-1) dry weight) in 5 mg kg~(-1) As (Ⅲ)-spiked soil media. In addition to As accumulation, A. yokoscense cultivated in soil taken from an old mining area accumulated Cu, Zn, Cd and Pb at concentrations a hundred times higher than those reported for other terrestrial plants. These results suggest that A. yokoscense is a good candidate to concentrate and remediate As and heavy metal-contaminated soils.