Understanding the processes that control the transport of metals in the environment is essential for a wide range of fields, including environmental protection and remediation, mineral resources, climate change. Through recent analytical developments, it is possible, using natural variations in metal isotopes, to identify and quantify how metal concentrations in natural waters are controlled by interactions with mineral surfaces, microbially-mediated reactions, and release during mineral weathering, and so significantly advancing our understanding of the fate and consequences of metal transport in the environment However, such applications have not been extensively exploited. The proposed MetTrans scientific and training Network will address a range of critical societal and industrial applications. This includes the abiotic and microbial immobilization of contaminants, the role of metals in carbon sequestration, and the response of metal transport to climate change. This requires interdisciplinary input, from chemistry, geology, physics, biology, hydrology, and engineering, and the solution to many of these problems requires close academic-industrial collaboration – academia will provide the scientific expertise and state-of-the-art analytical techniques to the practical applications confronted by industry. Although the particular research questions considered are diverse, the underlying scientific principles and analytical techniques are similar. This therefore provides an excellent platform to train young scientists in using of isotopic methods, understanding metal behaviour, and utilizing skills broadly. The Network focuses on providing training on analytical skills, on understanding fundamental principles, and on modelling, and exposes young scientists to a wide range of opportunities for applying this training in research and industry.