Microcosm Investigation on Phytoremediation of Cr Using Azolla Pinnata

The extent of Chromium (Cr) pollution in Singrauli industrial region, India was assessed and phytoremediation capacity of a small water fern, Azolla pinnata R.BR (Azollaceae) was observed to purify waters polluted by Cr under microcosm condition. Azolla pinnata endemic to India is a potential hyper-accumulator of heavy metals. During 13 days of the experiment the fern was grown in the aqueous medium containing Cr3+ and CrO42- ions, each in a concentration 0.5, 1.0, and 3.0 mg L-1. The presence of these ions caused a + 3.1 to -37.5% inhibition of Azolla pinnata growth in comparison to the control. After 13 days of the experiment, metal contents in the solution was decreased up to 70% (CrO42- 3.0 mg L-1 treatment) to 88% (CrO42- 0.5 mg L-1 treatment). In the Azolla pinnata tissues, the concentration of couple of the ionic forms of Cr under investigation ranged from 415 to 1095 mg kg-1 dry mass (dm); the highest level being found for Cr (III) containing solution.