• DOI:10.1579/0044-7447-38.2.110
• Corpus ID: 43473128

Accumulation of Cadmium and Copper from Aqueous Solutions Using Indian Lotus (Nelumbo nucifera)

@inproceedings{Mishra2009AccumulationOC,
  title={Accumulation of Cadmium and Copper from Aqueous Solutions Using Indian Lotus (Nelumbo nucifera)},
  author={Virendra Kumar Mishra},
  booktitle={Ambio},
  year={2009}
}

• V. Mishra
• Published in Ambio 9 March 2009
• Environmental Science

The application of phytoremediation in treating heavy metals from waste water has gained much attention during the last 2 decades. The metal hyperaccumulating properties of many plants, especially aquatic macrophytes, support the use of a plant-based system for treatment of waste waters containing metals (1). Macrophytes such as Eichhornia, Lemna, Spirodella, Azolla, Phragmites, and Pistia have been used for the removal of heavy metals from waste waters (1–5). These macrophytes are perennial aquatic weeds spread all over the world; they are considered noxious and extremely invasive in freshwater environments. Species of all the above genera take up metals from water, producing an internal concentration several times greater than surroundings (6) and showing a much higher metalaccumulating capacity and rate than nonhyperaccumulating terrestrial plants. Their higher biomass, greater removal efficiency, fibrous root system, and greater tolerance for metals make metal hyperaccumulating macrophytes excellent choices for the phytoremediation process (7). Indian lotus (Nelumbo nucifera) is a rooted macrophyte known to grow in polluted water bodies and eutrophic lakes; most importantly, it has a very wide occurrence throughout India. These characteristics suggest that Indian lotus could be used for phytoremediation. It is very important to evaluate the metal removal potential of this plant before its large-scale utilization for heavy metal phytoremediation. Therefore, the present study was performed to evaluate the removal capacity of the Indian lotus for two heavy metals, cadmium (Cd) and copper (Cu). Cadmium is a nonessential toxic heavy metal that can have significant effects on higher plants (8). It is mainly released into the environment by power stations, heating systems, metalworking industries, waste incinerators, urban traffic, cement factories, and as a byproduct of phosphate fertilizers (8). Cadmium has become an increasing problem and its toxic effects on biological systems have been reported by various authors. Although not essential for plant growth, Cd is readily taken up by the roots and translocated into the leaves in many plant species. Copper is an essential micronutrient for normal plant metabolism, playing an important role in a large number of metalloenzymes and in photosynthesis-related membrane structure; it has been reported to be among the toxic heavy metals. Excessive Cu accumulation in plant tissue can be toxic to the plants, affecting several physiological and biochemical processes and growth (9, 10). N. nucifera, 7–8 weeks old with approximately the same size and weight, were used for the removal of Cu and Cd. Prior to the experiment, the plants were washed thoroughly with tap water followed by deionized water. All plants were grown in duplicate in 15-L experimental tanks filled with 10 L water. A plant control (i.e., plants grown in tap water) and a metal control (i.e., metal solution without any plants) were also established. The concentration of metal ions in solution was determined before the commencement of the experiment. Solution samples were collected periodically from day 0 to day 7 from the experimental tanks for the determination of metal concentrations. Loss of water due to evaporation was made up daily by adding tap water to bring the level even with a mark in the experimental tank. Copper and cadmium were added to make their concentrations 1.0 mg L , 2.0 mg L , 5.0 mg L , and 10.0 mg L 1 in water. These heavy metals were added as cupric nitrate (Cu [NO3]2 3H2O) and cadmium nitrate (Cd [NO3] H2O). The reagents were dissolved in distilled water to achieve the desired contamination level, and these contaminants were added to all experimental sets. Experimental plants were harvested regularly on each of the 7 d of the exposure. Harvested plants were washed thoroughly twice with tap water followed by deionized water and were separated into roots, leaves, and stems. All parts were then oven-dried at 808C to remove all moisture. The oven-dried samples were ground to powder and stored for wet digestion for the analyses of Cu and Cd. Duplicate portions of ground plant material (1.0 g each) were weighed for analysis of metal concentrations, while 0.5-g plant materials were used for protein and sugar analyses. The plant samples for heavy metal analysis were ground and digested with HNO3 –HClO4 (2:1 v/v) and diluted to 100 mL with deionized distilled water. The digested plant samples were analyzed for heavy metals by means of atomic