Metal remediation potential of naturally occurring plants growing on barren fly ash dumps

摘要

The present study aimed to elucidate the remediation potential of visibly dominant, naturally growing plants obtained from an early colonized fly ash dump near a coal-based thermal power station. The vegetation comprised of grasses likeSaccharum spontaneumL.,Cynodon dactylon(L.) Pers., herbs such asTephrosia purpurea(L.) Pers.,Sida rhombifoliaL.,Dysphania ambrosioides(L.) Mosyakin & Clemants, Chromolaena odorata(L.) King & H.E. Robins along with tree saplingsButea monosperma(Lam.) Taub. The growth of the vegetation improved the N and P content of the ash. Average metal concentrations (mg kg(-1)) in the ash samples and plants were in order Mn (345.1) Zn (63.7) Ni (29.3) Cu (16.8) Cr (9.9) Pb (1.7) Cd (0.41) and Cr (58.58) Zn (52.74) Mn (39.09) Cu (10.71) Ni (7.45) Pb (5.52) Cd (0.14), respectively. The plants showed fly ash dump phytostabilization potential and accumulated Cr (80.19-178.11 mg kg(-1)) above maximum allowable concentrations for plant tissues. Positive correlations were also obtained for metal concentration in plant roots versus fly ash.Saccharum spontaneumshowed highest biomass and is the most efficient plant which can be used for the restoration of ash dumps.