Elephant Grass
On the grounds of Uckange's abandoned steelworks, just outside Thionville, islands of green are sprouting among the concrete and rusted metal. These are not decorative plants. They are part of an experiment to naturally clean up soil polluted with hydrocarbons and heavy metals.
The project is led by Sonia Henry, a lecturer at the University of Lorraine's institute of technology, who sows seeds in what she calls a transformation garden. The main species under trial is Miscanthus x Giganteus, known for its ability to thrive on industrial wastelands tainted by contaminants. Also called elephant grass, Miscanthus stimulates microorganisms around its roots. These microbes help lock metals in place, reducing their spread and aiding their breakdown by changing soil chemistry, including pH, thereby encouraging removal of pollutants.
Since 2022, the former ironworks have served as an open-air laboratory for phytoremediation, a process that uses plants to absorb, stabilise, or break down pollutants. The initiative, led by the Val de Fensch urban community with the University of Lorraine and INRAE, aims to find greener alternatives to excavation or chemical treatment, which can be costly and invasive.
What makes this pilot unique is its use of plant associations. In addition to Miscanthus, another plant, whose name is being kept confidential for now, has been introduced to specifically target metallic pollutants, especially zinc. This second species takes up metals from the soil and accumulates them in its above-ground parts. The contaminated plant matter remains contained and does not spread further. The goal is to find the right combinations so they can speed up decontamination and tackle multiple pollutants at once.
An old steelworks, a lecturer with seeds, and elephant grass doing what excavators cannot: cleaning the ground without tearing it apart.