Investigating Metals and Metalloids in Soil at Micrometric Scale Using µ-XRF Spectroscopy—A Case Study

Micrometric 2D mapping of distinct elements was performed in soil grain-size fractions a sample using the micro-X-ray Fluorescence (µ-XRF) technique. The collected vicinity São Domingos, an old mine massive sulphide minerals located Portuguese Iberian Pyrite Belt. As expected, elemental high-grade concentrations metals and metalloids dependence existent natural geochemical anomaly were detected. Clustering k-means statistical analysis developed considering Red–Green–Blue (RGB) pixel proportions produced micrometric image maps, allowing for identification spatial distributions at 2D. results evidence how composition varies significantly scale per class, chemical present irregular direct mineral distributions. Due to this fact, is more differentiated coarser classes, whereas griding-milled fraction does not always represent average all partial fractions. Despite complexity analysis, achieved suitability µ-XRF characterize natural, heterogeneous, granular soils samples scale, being very promising investigation technique high resolution.