Abstract:
Landfill sites open and close frequently throughout the world, taking over a significant
amount of land and leaving it contaminated and unavailable to the surrounding population for use.
Different forms of remediation methods have been employed to rehabilitate contaminated land to
a state that poses less of a threat to the environment. Phytoremediation is one of the remediation
techniques that has proven to be effective, economical and easier to implement compared to other
methods. The main aim of this study was to explore the potential use of Lolium perenne L. to remediate
and restore metal-contaminated landfill soil and determine its stress tolerance mechanism(s). The
metal uptake, determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES)
and inductively coupled plasma-mass spectroscopy (ICP-MS), revealed that Lolium perenne accumulate
a higher amount of metals in the roots than in leaves, which was further confirmed by the
translocation factor (TF) values of all of the metals that were below 1, ranging between 0.2 and 0.8,
while Cu, Cr and Pb had a bioaccumulation factor (BCF) > 1. This confirms that L. perenne is capable
of absorbing metals into the root matrix but might restrict further movement into other parts of the
plant as a defense mechanism against metal toxicity. In response to metal-induced stress, L. perenne
displayed an increase in enzyme activity of superoxide dismutase, glutathione S-transferase, peroxidase
and amylases in plants grown in landfill soil. Peroxidases displayed the highest level of
enzyme activity, while total amylolytic activity had the most significant increase in activity over time.
Although not a hyperaccumulator, L. perenne is a potential candidate for the phytoremediation of
landfill soil and the phytostabilization of Cu, Cr and Pb.
