Figure 1: Yield element maps (204 x 204 μm2) obtained from micro-PIXE analyses of arsenic-exposed lichen thallus of Hypogymnia physodes. The upper portion of the lichen thallus (upper cortex, algal layer and medulla, from left to right) is shown in detail. Maps are not corrected for sample thickness. The majority of elements are concentrated in the algal layer, except for calcium and manganese that are concentrated in the medulla. Peak manganese concentration in the medulla occurred due to arsenic-exposure. Reprinted with permission from [11].