European Journal of Biotechnology and Bioscience 15 European Journal of Biotechnology and Bioscience Online ISSN: 2321-9122, Impact Factor: RJIF 5.44 www.biosciencejournals.com Volume 4; Issue 10, October 2016; Page No. 15-20 Role of macrophytes in heavy metal removal through rhizo-filtration in aquatic ecosystem 1 Anjali Verma, 2 Ram Naresh Bharagava, 3 Venkatesh Kumar, 4 Ashima Singh, 5 Namita Dhusia, *6 Nandkishor More 1,5,6 Department of Environmental Science, School of Environmental Sciences 2 Department of Environmental Microbiology, School of Environmental Sciences 3 Department of Applied Animal Science, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India 4 Department of Botany, Banaras Hindu University, Varanasi, Uttar Pradesh, India Abstract Heavy metal pollution in an aquatic ecosystem due to anthropogenic activities poses a major threat to its viability and environmental sustainability. The present study is an attempt to investigate metal accumulation potential of metals Cd, Fe and biochemical aspects of aquatic macrophytes Eichhornia crassipes and Trapa natans as a model phytoremediation tool. Investigations have been carried out using Atomic Absorption Spectrophotometer and biochemical parameters of Chlorophyll, Protein, Proline, Malondialdehyde (MDA), Nitrate and Nitrite content. Our observations indicate that Eichhornia crassipes have high accumulation efficiency of Fe over Trapa natans. Among the plant parts, roots showed the high metal accumulation potential as compared to shoot. However on high concentration, metal accumulation photosynthetic pigments and protein content is reduced. A promotive effect on amino acid (proline content) and enzyme activities (Malondialdehyde content) has been observed under metal accumulation stress possibly because of altered membrane properties and enhanced lipid per oxidation pathway. The result shows that phytoremediation using these two model macrophytes is an efficient and economic strategy, and these species have enormous potential to reduce heavy metal stress in aquatic ecosystem however it affects biochemical indicators. Keywords: Heavy metals, Phytoremediation, Macrophytes, Aquatic ecosystem 1. Introduction Heavy metal pollution in an aquatic ecosystem poses a threat to aquatic biodiversity. Drinking contaminated water poses severe health hazards in humans. Among the various strategies adopted for removal of toxic heavy metals from the contaminated sites, phytoremediation has emerged as an economical, eco-friendly and aesthetically acceptable technology in the recent years (Cecchi and Zanchi, 2005 [2] ; Liu et al., 2010 [11] ; Sylwia et al., 2010; Huang et al., 2011 [7] ; Buddha and Singh, 2012 [1] ; Santana et al., 2012 [16] ; Stingu et al., 2012 [17] and Witters et al., 2012) [19] . Macrophytes are potent tools in the abatement of heavy metal pollution in aquatic ecosystems receiving industrial effluents and municipal wastewater. Aquatic macrophytes usually follow the mechanism of rhizo-filtration for metal removal (Salt et al., 1998 [14] ; Eccles et al., 1999 [4] ; Gardea-Torresdey, 2003) [6] . They are preferred over other bio-agents due to low cost, frequent abundance in aquatic ecosystems and natural handling. Water hyacinth (Eichhornia crassipes) is one of the most commonly used plants in constructed wetlands because of its fast growth rate and significant uptake of nutrients and contaminants (Rai, 2008a) [12] . This process involves raising plants hydroponically and transplanting them into metal- polluted waters where plants absorb and concentrate the metals in their roots and shoots (Dushenkov et al., 1995 [3] ; Flathman and Lanza, 1998 [5] ; Zhu et al., 1999 [20] ). Rhizofiltration offers a cost advantage in water treatment because of the ability of plants to remove up to 60% of their dry weight as toxic metals, thus markedly reducing the generation and disposal cost of the hazardous residue (Salt et al., 1995) [15] . Global research on heavy metals removal through phytoremediation using macrophytes is continuing in different countries (Keskinkan, 2005 [8] ; Lesagea et al., 2007 [10] ; Rai and Tripathi, 2009) [13] . However, the impact of accumulation of heavy metals on biochemical characteristics (Chlorophyll, Protein, Proline and Malondialdehyde) of macrophytes is not entirely understood. The present study is aimed to investigate and compare the metal accumulation efficiency of macrophytes namely (Eichhornia crassipes and Trapa natans), metal translocation in different plant parts and to evaluate the impact of heavy metals on biochemical parameters of aquatic plants. 2. Material and Methods 2.1 Experiment Design All the sampling and experiments were completed in urban areas of Lucknow district. The healthy plants of Eichhornia crassipes (Family: Pontederiaceae; Common name: Water hyacinth) and Trapa natans (Family: Lythraceae; Common name: water chestnut, singhara) were selected as test plants. Cadmium (Cd) and Iron (Fe) taken as test metals with different concentrations. 1.0 ppm, 3 ppm, 6 ppm 12 ppm for Cd and 10 ppm, 20 ppm, 30 ppm, 40 ppm for Fe. A stock solution of the Fe (1000 ppm) and Cd (1000 ppm) was prepared using cadmium nitrate and ferric chloride and maintained in tubs by diluting the stock solution. The healthy plants of Eichhornia crassipes were collected from the pond water in the Mohanlalganj site Lucknow while plant of Trapa natans was collected from the pond water in the Nigoha Lucknow. The plant samples are cleaned under the running tap water to eliminate any remains of sediment and particles. Uniform size and healthy weighted plants were chosen placed in plastic tubs (5.0 liters capacity) flooded with ground water and containing different concentrations of Cd