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Heavy metals/metalloids remediation from wastewater using free floating macrophytes of a natural wetland

Rai, Prabhat Kumar
Environmental technology & innovation 2019 v.15 pp. 100393
Eichhornia crassipes, Pistia stratiotes, Spirodela polyrhiza, arsenic, biodiversity, cadmium, chromium, copper, environmental technology, heavy metals, human health, iron, macrophytes, nickel, phytoremediation, wastewater, wetland plants, wetlands, zinc
Potential bio-agents in context of phyto-technological innovation for removal of heavy metals/metalloids have been tightly linked with amelioration of environmental and human health. The present research investigated the prospective of three wetland plants Pistia stratiotes (water lettuce) Spirodela polyrhiza (a duckweed), and Eichhornia crassipes (water hyacinth) for synchronized multi-metallic removal of six hazardous/non-essential metals (Fe, Cu, Cd, Cr, Zn, Ni) and As (a metalloid) from a Ramsar site of a biodiversity hotspot. Results revealed high removal (>79%) of different metals during 15 days experiment in microcosms. Further, a saturation limit was reached in relation to heavy metals/metalloid removal, and thus it declined after two weeks of phytoremediation experiment in case of water lettuce and water hyacinth (about 8 days saturation limit noticed for duckweed). In the context of phyto-technological efficiency of selected wetland plants, E. crassipes was the most efficient for the removal of selected heavy metals followed by P. stratiotes and S. polyrhiza Significant correlations between metal concentration in remediated water and wetland plants/macrophytes were obtained. Therefore, these wetland plants may be used in devising eco-friendly remediation of hazardous heavy metals from wastewater.