Decontamination and/or revegetation of fly ash dykes through naturally growing plants

Present study is focused on the decontamination and/or revegetation of fly ash dykes through naturally growing plants, namely Calotropis procera, Cassia tora, Chenopodium album, Sida cardifolia, Blumea lacera. The results of sequential extraction study showed that maximum amount of metals (Na, K, Fe, Mn, Cr, Pb, Ni, Cd) were associated with residual and Fe-Mn fractions. Diethylenetriamine penta acetic acid (DTPA)-triethanolamine (TEA) extraction assessed the bioavailability of the metals. The total metal accumulation in tested plants was found in the order; C. album > S. cardifolia > C. tora > C. procera > B. lacera. The maximum bioconcentration factor (BCF) was recorded in S. cardifolia for the metals (Na, Fe, Zn, Cd), in C procera for the metals (Mn, Cu, Ni, Cr) and in C. album for the metals (Co, Pb). However, the translocation factor (TF) of most of the metals was found more in S. cardifolia followed by C. album than other plants. Among all the plants, C album have shown high BCF and low TF values for toxic metals (Pb, Cd) and suitable for phytostabilization of these metals. Principal component analysis was used to predict translocation behavior of the metals in different parts of the plants which was found similar for the metals (Cu, Zn, Mn, Cr). All examined plants are suitable for revegetation (naturally grows on fly ash dykes) and S. cardifolia and C album may be used for decontamination purposes. (C) 2007 Published by Elsevier B.V.