Metals are prevalent in the environment. They are derived from both natural and anthropogenic sources. Certain metals are essential for plant growth and for animal and human health. However, at excessive levels they are toxic. Metals undergo an array of processes, including sorption/desorption, precipitation/dissolution, and oxidation/ reduction, with reactive natural surfaces such as clay minerals, metal oxides, humic substances, plant roots, and microbes. These biogeochemical processes control the solubility, mobility, bioavailability, and toxicity of the metals. This issue of Elements will explore research frontiers in the areas of metal mobility and reaction mechanisms on natural surfaces. These advances will be explored at multiple scales, using state-of-the-art analytical techniques.
