Phytoremediation of soils

Phytoremediation is the use of plants and their associated micro-organisms to contain, inactivate, degrade or eliminate soil contaminants. It is mainly applied to chemical contaminants, organic molecules or elements hazardous to human health, that of other living beings or ecosystems. The plant creates favorable conditions for treating the pollutant, or acts directly on it. This is a biological treatment, generally applied in situ or on site, based on agronomic techniques that vary according to the class of pollutant and the characteristics of the soil or site being treated. The process is reputed to be inexpensive, since it is partly solar-powered and, in some cases, the plant biomass produced can be recycled. It has the advantage of fixing CO ₂ , preserving soil morphology and functions undisturbed by contamination, and restoring or improving functions impaired by pollution. This treatment method does not cause the nuisance of a mechanized treatment site and, from a visual standpoint, often allows the site to be reintegrated into its environment. Phytoremediation should make it possible to treat moderately contaminated soils, such as those that have undergone certain industrial activities, but also those affected by less intense contamination but over larger areas, such as agricultural land that has suffered diffuse pollution.

However, all these advantages are more potential than proven, as phytoremediation is still an emerging process. It is the subject of a great deal of research, with the aim of overcoming the scientific and technological hurdles it faces. Phytoremediation is relatively little used in practice, and when it is, particularly in phytostabilization or rhizodegradation, we don't yet have enough information to properly evaluate the process.

In this article, we present the main processes involved in soil phytoremediation, as well as the different processes that this term covers. We conclude with a look at current and planned research projects.