Phyto-remedial potential of aquatic plants for heavy metals contaminated industrial effluent

The present research was conducted to assess the potential of 3 native aquatic macrophytes/ plant species Water Hyacinth (Eichhornia crassipes), Water Lettuce (Pistia stratiotes) and Coontail (Ceratophyllum demersum) by growing on heavy metal contaminated industrial effluent collected from the Fuse Shop of Pakistan Ordinance Factory, Wah Cantt, Rawalpindi. After initiation of the experiment, the plant shoots and associated effluent samples were collected periodically, i.e. after every 6 days interval the experiment was terminated on 24th day. The collected shoots and effluent samples were analyzed for total Cu, Cr, Cd, Zn, Ni and Pb concentrations. The initial concentration of metals in industrial effluent was observed as Cu (3.35 mg L-1), Ni (3.81 mg L-1), Pb (3.42 mg L-1), Cr (3.73 mg L-1), Zn (2.66 mg L-1) and for Cd (3.33 mg L-1). It was observed in the Water Hyacinth treated effluent, the concentration of metals reduced for Cu (0.00 mg L-1), Ni (0.20 mg L-1), Pb (0.002 mg L-1), Cr (0.2 mg L-1), Zn (0.02 mg L-1) and for Cd (0.01 mg L-1) at the end of the experiment. Water Lettuce reduced the metal concentration of Cu (0.03 mg L-1), Ni (0.00 mg L-1), Pb (0.002 mg L-1), Cr (0.1 mg L-1), Zn (0.02 mg L-1) and Cd (0.001 mg L-1) in the industrial effluent. Coontail reduced the concentration of heavy metals i.e. Cu (0.05 mg L-1), Ni (0.00 mg L-1), Pb (0.00 mg L-1), Cr (0.13 mg L-1), Zn (0.1 mg L-1) and Cd (0.00 mg L-1) in the effluent. The total metal concentration observed in the phytoremediation plants was different for different metals. The maximum metal concentration removed by Water Hyacinth was 68.4 g-20L and 64.7 g-20L for Cr and Cu, respectively. The total metal concentration removal by Water Lettuce for Cu was relatively more than Water Hyacinth i.e. 65.1 g-20L. Coontail efficiently removed highest metal concentration of Cu (73.7 g-20L), Ni (78.1 g-20L), Cr (76.1 g-20L) and Cd (70.5 g-20L) from the industrial effluent than both Water Hyacinth and Water Lettuce. Hence, Coontail was found efficient for the removal of heavy metals from the effluent as compared to Water Hyacinth and Water Lettuce. The studied outcomes of this research can be used for managing and decontamination of industrial effluent with heavy metals.