The ID 21 Beamline has been a pioneer in the use of X-ray microspectroscopy applied to environmental and earth sciences. Materials analyzed at the beamline encompass a broad spectrum from nano-engineered materials to soils and plants. Within the materials investigated under environmental and earth sciences, a common aim is to trace their fate (localization) and change (speciation) in the environment. Research encompassing nanomaterials focuses on their potential accumulation and transference within distinct trophic levels. On the other hand, research on nutrient or pollutant fate focuses on the speciation of elements, within different matrixes. On this page, we review the most recent applications of ID21 instruments in the field of environmental and earth sciences.