Active industrialisation in the Walloon basin since the 19th century has produced significant quantities of residual substances. Often used for backfilling, these materials contribute to the anthropization of Walloon soil over large surfaces. In terms of eco-compatibility, anthropic soils in particular, due to steel residue (artificial anthroposoil) often presenting total concentrations of metal trace elements (MTE) greater than the limits in the current standards, which is a matter for serious concern for managers and public decision-makers. In fact, the imperatives related to the decree concerning soil management requires the clean-up of polluted sites. This constraint leads to high clean-up costs and may result in considerable technical difficulties during the rehabilitation of the sites concerned. Since the mobility and bio-availability levels of MTEs mainly depends on the nature of mineral carriers, the current research, performed in partnership with the ULg and GéoRessources (France), aims to identify the latter and specify their future based on a multi-level approach.
The research objectives are as follows:
- to assess the real environmental risk from Walloon artificial anthroposoil;
- to develop a simple method able to identify, on the ground, the major backfilling constituting Walloon artificial anthroposoil.