remediate various pollutants from environment (Debusk et al., 2001). The macrophytes have
high biomass which helps to uptake nutrients and heavy metals. Typha spp. is a macrophyte
which has a considerably high nutrient uptake capacity (Maddison et al., 2009). Macrophytes
have a metabolic role in wastewater treatment due to their potential to release oxygen into the
rhizosphere which helps in nitrification and by direct uptake of nutrients (Greenway and
Metal ions cannot move across the cellular membranes due to their charge. Ion transport into
cells is mediated by transporters. The transmembrane structure facilitates the transfer of ions
from extracellular space through the hydrophobic environment of the membrane into the cell.
The ions associated with the roots are absorbed into the cells. A significant amount of ion is
adsorbed at the extracellular negatively charged sites of the root cell walls (Seuntjens, 2004).
The cell wall bound fraction is not translocated to the shoots. For phytoextraction, metals must
be transported from the root to the shoot.
The common aquatic plant species (Typha latifolia, Myriophyllum exalbescens, Potamogeton
epihydrus, Sparganium angustifolium, Myriophyllum spicatum and Sparganium
multipedunculatum) have been reported for aluminium (Al) phytoremediation (Gallon et al.,
2004). Parrot feather (Myriophyllum aquaticum), creeping primrose (Ludwigia palustris), and
water mint (Mentha sp.) have been reported for phytoremediation of iron (Fe), zinc (Zn),
copper (Cu), and mercury (Hg) from water (Kamal et al., 2004). The L. minor has been studied
for phytoremediation of Cu and cadmium (Cd) from contaminated soils (Hou et al., 2007).
Wetlands are shallow water, low dissolved oxygen (DO), and saturated soils. Wetlands are of
two types, natural and constructed wetlands. Natural wetlands act as ecosystem filters (Cheng
et al., 2002), while constructed wetlands are artificially engineered systems which acts as
biofilter by removing nutrients and heavy metals from the water. Wetland plants have the
ability to remove pollutants and excess mineral nutrients from the water and soils (Romero et
The selection of plants for a wetland is important where phytoremediation is to be applied.
Wetland plants are divided into emergent, submerged and floating. The emergent plants are
rooted in the soil with basal portions, and leaves, stems and reproductive organs are aerial
(Herath and Vithanage, 2015). Emergent species are used for phytotranspiration,
phytoextraction, and phytovolatilization and are easy to harvest. The examples of emergent
plants are Phragmites australis, Typha domingensis, Typha latifolia, Phragmites karka, Juncus
pallidus, Empodisma minus, Phalaris arundinacea, Scirpus cyperinus, Aster novae-angliae,
Limonium carolinianum, Cephalanthus occidentalis and Rhizophora mangle. Submerged