This thesis shows how the Process Analysis Method (PAM) can be applied to assess technologies used to mitigate arsenic from drinking water in rural India, using a set of sustainability indicators. Stakeholder perspectives, gathered from a fieldwork survey of 933 households in West Bengal in 2012, played a significant role in this assessment. This research found that the ‘Most Important’ issues as specified by the technology users are cost, trust, distance from their home to the clean water source (an indicator of convenience), and understanding the health effects of arsenic. It was also found that none of the ten technologies evaluated are economically viable, as many do not charge user-fees, which creates reliance upon donations to meet recurring costs. Utilisation of a technology is strongly related to sociocultural capital, but in many cases, features that contribute to sociocultural value, like regular testing of the treated water, are not included in the financial budget. It is suggested that increased awareness might change attitudes to arsenic-rich waste and its disposal protocols. This waste is often currently discarded in an uncontrolled manner in the local environment, giving rise to the possibility of point-source recontamination. All technologies proved to have difficulties in dealing with waste, except the Tipot and Dug wells which produce no waste. Of the methods considered, the BESU technology scored highest, but still only with 47-62% of the maximum scores achievable within each domain. This explains the widespread failure of mitigation projects across the region. The indicators and metrics show where improvements can be made. A model scheme based on these findings is outlined which could be applied with the objective of increasing utilisation and improving sustainability. It can be concluded that a product stewardship approach should be taken in regard to design, implementation and operation of the technologies, including the creation of a regulated toxic waste collection and disposal industry.

Dans les écosystèmes forestiers pauvres en nutriments, les minéraux du sol constituent la principale source de nutriments inorganiques nécessaires à leur bon fonctionnement. Néanmoins ces nutriments ne sont pas directement accessibles aux racines des arbres. C'est l'action conjointe de facteurs abiotiques, comme le pH ou la circulation de l'eau, et biotiques comme les racines ou les microorganismes du sol dont les bactéries, qui vont conduire à l'altération de ces minéraux. A ce jour, nos connaissances sur les communautés bactériennes impliquées dans le processus d'altération et leur distribution dans des sols forestiers restent limitées, notamment à des habitats tels que la rhizosphère et la mycorhizosphère. Les objectifs de cette thèse étaient de caractériser les communautés bactériennes colonisant les minéraux du sol et leur aptitude à altérer les minéraux et enfin d'identifier les gènes bactériens impliqués. La combinaison d'approches cultivable, non cultivable et de biogéochimie sur des minéraux enterrés pendant 4 ans dans un sol forestier, a démontré que leur surface était colonisée par des communautés bactériennes spécifiques, capables d'altérer les minéraux et présentant des capacités métaboliques limitées, suggérant que ce support pourrait être considéré comme un habitat : la minéralosphère. La relation minéral/bactéries a été testée in situ via un amendement minéral sur une plantation et a mis en évidence l'impact de la disponibilité en nutriments sur la structuration des communautés bactériennes capables d'altérer les minéraux. L'étude génétique réalisée sur la souche modèle PML1(12) a révélé l'implication de plusieurs mécanismes dans la fonction altération / In nutrient-poor forest ecosystems, minerals are the main source of inorganic nutrients for the long lasting functioning of the forests. However, these nutrients are not directly accessible to the tree roots. It is the joined action of abiotic factors, such as pH and water circulation, and biotic factors such as tree roots and soil microorganisms, and notably bacteria, which leads to the solubilisation of these minerals. To date, our knowledge of the bacterial communities involved in the mineral weathering process and their distribution in forest soils is very limited and remains restricted to habitats such as the rhizosphere and mycorrhizosphere. The goals of this PhD thesis were to characterise the mineral associated bacterial communities, their ability to weather minerals and finally to identify the bacterial genes involved in the mineral weathering process. The combination of geochemical, cultivation-dependent and -independent approaches applied on minerals grounded in a forest soil during 4 years, revealed that the mineral associated bacterial communities were specific, able to weather minerals and had restricted metabolic abilities. These results suggest that minerals could be considered as a true ecological habitat: the mineralosphere. The mineral/bacteria relationship was tested in situ through a mineral amendment applied on a small-scale plantation, which has highlighted that the nutrient availability impacted the functional structure of the mineral weathering bacterial communities. At least, random mutagenesis applied on a model mineral weathering bacterial strain revealed that its mineral weathering ability resulted from several molecular mechanisms