Sustainable management of sites affected by past industrial activities in Wallonia: the stakes and the challenges of risk assessment within the framework of the new policy developments on (local) soil pollutions. Risk-based land management is a concept that stands out more and more frequently in soil policies adopted by different European countries, as well as within the framework of the future European directive on soil protection. This concept intends to act as a lever for sustainable solution development in terms of rehabilitation by ensuring the following principles: (1) reduction of risks (human health, ecosystems) allowing sites to be reused safely (concept of fitness for use); (2) prevention of any pollutant dispersion risk (concept of environmental protection); (3) long-term care while minimising the burden of controlling, maintenance and monitoring. These ideas have been taken as backdrop for the Walloon decree on soil remediation and rehabilitation of disused economic activity sites. Risk control has been taken as a key point for any decision related to historically polluted sites. However, to be effective, this option stands out that reliable and efficient methodological tools are available for land evaluation (risk assessment). Three decision-making tools, specifically developed for the intended applications in the Walloon Region, are presented in the paper: (1) a global risk evaluation method allowing ranking of polluted sites; (2) a method to decide, at the end of the first step of the investigation procedure (preliminary soil investigation), whether further investigations are required or not; (3) a methodological procedure to proceed to a detailed risk assessment at the end of the in-depth investigation step. Perspectives are proposed to improve these first tools. It has also been shown that the challenge of sustainable solutions for the management of polluted sites finally depends on answers that will be progressively developed by the scientific community. These have to take into account all aspects of the Walloon context.
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