Phytoremediation of heavy metals from fly ash pond by Azolla caroliniana

Abundance of naturally growing Azolla caroliniana (water fern) on the surface of metal enriched fly ash (FA) pond reflects its toxitolerant characteristics. Results indicate the efficiency of A. caroliniana for phytoremediation of FA pond because of its higher bioconcentration factor. The metal concentration ranged from 175 to 538 and 86 to 753 mg kg−1 in roots and fronds, respectively. Bioconcentration factor (BCF) values of all metals in root and frond ranged from 1.7 to18.6 and 1.8 to 11.0, respectively, which were greater than one and indicates the metal accumulation potential of A. caroliniana. Translocation factor (TF) ranged from 0.37 to 1.4 for various heavy metals. The field result proved that A. caroliniana is a potential accumulator for the examined heavy metals and can be used for phytoremediation of FA pond.

► Fly ash pond causes severe toxic metals pollution through leaching.
► Azolla caroliniana (water fern) grows naturally in FA pond.
► A. caroliniana shows higher bioconcentration factor of Cu, Cr, Pb and Ni.
► A. caroliniana can be used for phytoremediation of FA ponds.