Abstract
Groundwater provides a significant proportion of the water supply of the territories.The monitoring of the reserves and quality of these resources is therefore a major issue,in line with the United Nations Sustainable Development Goals. In relation to theseobjectives, this thesis deals with the characterization of the quality of groundwaterbodies in a territory with a mining past. It aims at developing a methodology toestimate the respective contributions of the natural geochemical background andanthropogenic inputs to the enrichment of metals and metalloids in groundwater,considering simultaneously the heterogeneity of the geology and the combination ofgeological, geomorphological, tectonic and statistical factors. Quality measurementswere carried out to establish the state of arsenic and antimony concentrations in thegroundwater bodies delimited by the Gardon watershed in the Cevennes. Then, amulti-criteria aggregation operator was developed and implemented in order toproduce quantitative and qualitative maps allowing the discrimination of the naturalgeochemical background from the anthropic contributions mainly constituted by thepast mining activity. This mapping made it possible to determine remarkable focilocated in particular on the Cevennes fault and on which particular attention must bepaid in the context of territorial management of the quality of water resources. Aninteractive workshop allowed to evaluate the differences of perception of the actors ofthe territory in front of information on water quality. It highlighted the need to developadapted scientific information restitution supports in order to reach a sharedawareness of groundwater quality issues by the different actors of a territory.