5. Free-floating aquatic plants
Based on the literature, frequently used aquatic macrophytes for the heavy metal remediation in aquatic system were water hyacinth (Eichhornia crassipes), duckweed (Lemna minor) and water lettuce (Pistia stratiotes) [78,79]. These three free floating aquatic plants which are dominant in phytoremediation process and are shown in Fig. 1.