Authors:
Hermine Huot | Laboratoire Sols et Environnement / INRA-Université de Lorraine | France
Dr Patrick Charbonnier | Arcelor Mittal France | Luxembourg
Prof. Marie-Odile Simonnot | Université de Lorraine - CNRS | France
Prof. Jean-Louis Morel | University of Lorraine | France
Green Management and Ecosystem Services of Former Industrial Decantation Ponds
Hermine Huot1,2,3,4, Patrick Charbonnier4, Marie-Odile Simonnot2,3, Jean Louis Morel1,2
1Université de Lorraine, Laboratoire Sols et Environnement, UMR 1120, Vandoeuvre-lès-Nancy, F-54518, France
2INRA, Laboratoire Sols et Environnement, UMR 1120, Vandoeuvre-lès-Nancy, F-54518, France
cUniversité de Lorraine, Laboratoire Réactions et Génie des Procédés, UMR 7274, Nancy, F-54001, France
3CNRS, Laboratoire Réactions et Génie des Procédés, UMR 7274, Nancy, F-54001, France
4Environment & Development, ArcelorMittal Corporate Real Estate, L-1160 Luxembourg
The steelmaking process generates numerous metal-rich by-products. Black furnace sludge were often disposed of in settling ponds, which now require special attention regarding the risks they generate for environmental bodies and human health as a result of their high concentration of metals (e.g. Pb, Zn). After closure and termination of sludge deposits, a vegetation cover may develop, which raises the question of the sustainability of this mode of management analogous to a natural attenuation.
In this context, a former industrial decantation pond closed in the 1950’s, and covered with an alluvial deciduous forest, was characterized i) to assess the risk of transfer of metals to groundwater and organisms and ii) to study the potential influence of vegetation, and in particular roots, on the mobilization of metals. A thorough characterization of the soil developed on the deposits along with lysimeter experiments were conducted. Results showed that a significant range of soluble compounds (sulfates, carbonates) may be released in water, but that metal flow is rather negligible due to low soil permeability and low metal solubility. Also, the presence of vegetation reduces water flow and limits the risk of transfer to groundwater. In contrast, in the rhizosphere soil, extractability of metals may increase as a result of root activity suggesting a potential mobilization of metals in the long term. In conclusion, risk of transfer of metals to groundwater and organisms is limited because of the presence low solubility of metal compounds and of specific physical properties of the sludge materials, which are in favor metal retention. In terms of site management, the presence of a dense vegetation cover prevents dust hazard, stabilizes materials and limits water flow and thus risk of transfer to groundwater. Changes caused by roots on the chemical status of metals are limited in space, but must be monitored to support to this management option.
[1] Huot, H. (2013). Formation, fonctionnement et évolution d'un Technosol sur des boues sidérurgiques, Thèse de doctorat, Université de Lorraine, France.
[2] Huot H., Simonnot M.O., Marion P., Yvon J., De Donato P., Morel J.L. (2013). Characteristics and potential pedogenetic processes of a Technosol developing on iron industry deposits, Journal of Soils and Sediments, 13(3):555-568, doi 10.1007/s11368-012-0513-1
[3] Huot H., Simonnot M.O., Watteau F., Marion P., Yvon J., De Donato P., Morel J.L. (2013). Early transformation and transfer processes in a Technosol developing on iron industry deposits, European Journal of Soil Science, doi: 10.1111/ejss.12106.