Vermiremediation of metal(loid)s via Eichornia crassipes phytomass extraction: A sustainable technique for plant amelioration

Abstract

Eichhornia crassipes (water hyacinth), imparts deficiency of soluble arsenic and other toxic metal (loid)s through rhizofiltration and phytoaccumulation. Without proper management strategy, this phytoremediation of metal (loid)s might fail and get reverted back to the environment, contaminating the nearby water bodies. This study, focused on bio-conversion of phytoremediating hyacinths, spiked with 100 times and greater arsenic, lead and cadmium concentrations than the average water contamination, ranging in 58.81 ± 0.394, 16.74 ± 0.367, 12.18 ± 0.153 mg Kg−1arsenic, 18.95 ± 0.212, 9.53 ± 0.054, 6.83 ± 0.306 mg kg−1 lead and 2.79 ± 0.033, 1.39 ± 0.025, 0.92 ± 0.045 mg kg−1 cadmium, respectively in root, shoot and leaves, proving it's phytoaccumulation capacity. Next, these hyacinths has been used as a source of organic supplement for preparing vermicompost using Eisenia fetida following analysis of total metal content and sequential extraction. Control soil was having 134.69 ± 2.47 mg kg−1 arsenic in compare to 44.6 ± 0.91 mg kg−1 at premature stage of compost to 23.9 ± 1.55 mg kg−1 at mature compost indicating sustainable fate of phytoremediated vermicompost. This vermiremediation of arsenic and other toxic elements, restricted the bioavailability of soil pollutants. Furthermore, processed compost amended as organic fertilizer, growing chickpea, coriander, tomato and chilli plant, resulted in negligible metal(loid)s in treated samples, enhancing also plant's growth and production.