Phytoremediation of 137cesium and 90strontium from solutions and low-level nuclear waste by Vetiveria zizanoides.

ABSTRACT

Vetiver grass (Vetiveria zizanoides) L. Nash plantlets when tested for their potential to remove (90)Sr and (137)Cs (5 x 10(3) k Bq l(-1)) from solutions spiked with individual radionuclide showed that 94% of (90)Sr and 61% of (137)Cs could be removed from solutions after 168 h. When both (90)Sr and (137)Cs were supplemented together to the solution, 91% of (90)Sr and 59% of (137)Cs were removed at the end of 168 h. In case of (137)Cs, accumulation occurred more in roots than shoots, while (90)Sr accumulated more in shoots than roots. When experiments were performed to study the effect of analogous elements, K(+) ions reduced the uptake of (137)Cs, while (90)Sr accumulation was found to decrease in the presence of Ca(2+) ions. Plants of V. zizanoides could also effectively remove radioactive elements from low-level nuclear waste and the level of radioactivity was reduced below detection limit at the end of 15 days of exposure. The results of the present study indicate that V. zizanoides may be a potential candidate plant for phytoremediation of (90)Sr and (137)Cs.