Deep-sea tailing practices: contamination and societal perspectives. Lessons learnt from the French success story of the Gardanne plant discharge in reducing environmental footprint.

What is the impact of discharging mining waste residues into the sea, both in terms of marine environment contamination and its societal dimension? This question is at the heart of the INTERFACES project, an interdisciplinary study focusing more specifically on the discharges from the Gardanne alumina production plant (southern France) into the Mediterranean Sea. The case of the Gardanne plant embodies the contemporary challenges of managing waste generated by its activity. It illustrates the modern conflict between industrial and environmental concerns. It also serves as an example of how marine contamination levels can be improved when adequate human, technological, and financial resources are properly mobilized. However, these advances have taken place within a significant context of environmental controversy spanning several decades. The Gardanne plant has been active since the late 19th century. It took nearly 55 years of contentious public debate and challenges before the sea discharges, initiated in the 1960s, met the requirements of the Barcelona Convention (1976) and its protocols. The period from 2012 to 2022 marks a pivotal decade in addressing this discharge issue, distinguished by significant advancements both scientifically and technologically as well as administratively and socio-politically, leading to compliance and a medium-term perspective of zero sea discharge. We examine the modalities of production, dissemination, and circulation of scientific information over this decisive decade, shedding light on the interactions between institutional actors and stakeholders of the Gardanne plant involved in the committees for evaluation and monitoring of discharges, including civil society. Our presentation focuses on the lessons learned from this complex interaction between mobilized resources, environmental improvement in terms of chemical contamination, and scientific communication around these processes. Based on a situated analysis of the risks and measures under debate in the case of the Gardanne plant, our study aims to explore methodological avenues for designing action strategies and information and exchange interfaces. These are centered on open access to information and stakeholder participation, as well as the public visibility and involvement of researchers engaged in scientific work. These strategies and interfaces will be configured and tested in case studies presenting similar contexts of environmental conflict. The Gardanne case serves as a reference element in terms of method, results, and governance, ensuring transparency in decision-making and stakeholder involvement for the management and monitoring of this type of Installation Classified for the Protection of the Environment.