Phytoremediation of trace elements contaminated soils has faced numerous challenges since this technology appeared as a promising option for the reduction of soil toxicity and its associated environmental risks. The conditioning of the soils to allow plant survival and adequate growth, the selection of the most appropriate plant species for each particular site and final aim (stabilization/extraction) and the management of the biomass generated can be considered the three main issues to be addressed for the implementation of phytoremediation. These concerns become specially challenging when semi-arid conditions apply, as is the case in the Region of Murcia (SE Spain). The creation of a vegetation cover in these soils can be quite a difficult task; common impaired soil properties and low fertility in contaminated areas are often exacerbated in (semi)arid regions, which makes the restoration of these sites particularly complex.

Different organic and inorganic waste materials have been used for the amelioration and conditioning of soils in phytoremediation processes. There is a general interest in the use of waste materials (manures, agri-food byproducts, municipal solid waste, etc.) with this aim, as this is a sustainable way for the recycling and re-utilization of these residues. The selection of the most adequate amendments for the improvement of the soil conditions is crucial for the correct development of the plants. However, changes in the properties and chemical composition of the soil normally result in changes in the solubility, mobility, speciation and bioavailability of some trace elements, which may condition the success of the restoration process. Decreased solubility/availability of the metals can be a preferred side effect of the use of soil amendments when the goal is the immobilization of the contaminants in the soil. The opposite effect (i.e. mobilization or increased availability) can lead to limitations in the use of specific materials in the presence of certain elements (e.g., As, Cd, Mn or Zn), or to the need of using combinations of amendments to improve the efficiency of the process.

Regarding plants, the use of native or locally adapted species offers the potential to overcome the restrictions provoked by (semi)arid climate for their adequate growth. This, together with their tolerance to the presence of trace elements in the soil, makes this type of plants of special interest for the phytomanagement of trace elements contaminated sites. Obtaining economic and ecological profits from this biomass has received wide attention, and there is a general consensus that this would turn the use of these technologies into reality, now that their options for success and viability have been extensively proved.

Transformation of the plant biomass obtained in phytostabilization in a source of renewable energy or in a stabilized material that can be stored, transported and used as soil conditioner are the proposed ways to make these processes cost-effective and of net interest in real remediation approaches. This can be achieved through thermal conversion for energy production, through anaerobic digestion for the production of biogas or through the composting of the biomass.