Forensic soils include all types of coverings formed by loose elements such as sand, mud, soils or dust, coming from different places and environments, even heavily anthropized, whose particles can adhere to surfaces of different nature, providing traces as possible evidence in forensic applications. The analysis soil traces found at the scene of a crime or on objects belonging to a suspect provide important information to connect a person to a place and to clarify the dynamics of a crime, because it can be transferred from one place to another for simple deposition on mobile surfaces (footwear, tires, vehicle mats, etc.).
Soils are complex systems consisting of numerous components that formed and developed during its formation process. Because of this complexity, the particles that make up the various types of sediments are of different nature and typology and present in extremely different quantities. Therefore, considerable differences are observed between one sample and another, to the point of recording considerable variations in the components and their proportions, in areas of very limited extension and already a few centimeters deep. For such evidence, soil analysis are an excellent support to judicial investigations.
Soil analysis include numerous techniques aimed at studying the structure and texture of the sediment, at identifying the nature and type of particles and at evaluating their relative proportions. Soils analysis are carried out following the international guidelines, published by the IUGS Initiative on Forensic Geology (pertaining to UNESCO) and by the Center for Australian Forensic Soil Science (CAFFS), and include optical and electronic microscopy, sedimentological and physical technics and spectroscopic techniques and are carried out in ISO 9001 and ISO 17025 certified laboratories:
Morphological analysis in stereoscopic microscopy
Mineralogical-petrographical analysis in thin section with polarized light microscope (PLM)
X-ray diffractometry (XRD)
Scanning electron microscopy (SEM-EDX)
Fourier Transform Infrared Spectroscopy (FT-IR)
Thermal analyzes (TG, DTA, DSC)