Context
Active industrialization in the Walloon basin since the 19th century has produced large quantities of waste materials. Most often used as fill, these materials have contributed to the anthropization of Walloon soils over kilometre-long areas. In terms of eco-compatibility, soils anthropized in particular by residues of iron and steel origin (as in the case of artificial anthroposols) often show total concentrations of trace metal elements (TMEs) in excess of current normative limits, which is a serious concern for public managers and decision-makers. In many cases, the requirements of the Soil Management Decree mean that polluted sites have to be cleaned up. Such a constraint entails high sanitation costs, and can lead to considerable technical difficulties when it comes to rehabilitating the sites concerned. Since the rate of mobility and bioavailability of TMEs depends mainly on the nature of the mineral carriers, current research, carried out in partnership with ULg and GéoRessources (France), aims to identify the latter and specify their fate on the basis of a multi-scale approach.
Objectives
The research objectives are as follows:
- clarify the real environmental risk of Walloon artificial anthroposols to ecosystems;
- develop a simple method capable of identifying, in the field, the major fills that make up Wallonia’s artificial anthroposols.