Advances in the Use of Synchrotron Radiation to Elucidate Environmental Interfacial Reaction Processes and Mechanisms in the Earth's Critical Zone

Reactions occurring at biogeochemical interfaces such as mineral/water, mineral/microbe, and plant/soil, greatly influence a number of important processes in soil and water environments. These include: sorption, desorption, oxidation-reduction, and precipitation, dissolution. It is useful to study these processes over a range of spatial and temporal scales. The use of molecular scale techniques, especially those that are in-situ and synchrotron-based, have provided a wealth of information on reactivity at biogeochemical interfaces. This review focuses on the use of these techniques, especially X-ray absorption spectroscopy, to speciate and elucidate reaction mechanisms of metal(loids) in soils and plants.