Možnosti analýzy stop zeminových fází v kriminalistické znalecké praxi
Analysis of pedological phasesin forensic practise

Summary/Abstract: Analysis of pedological phases that adhered to clothing, footwear, vehicles, or other objects is relatively frequently required in forensic practice to confirm the place of origin of contamination. These are basically two types of tasks. This entails either standard comparisons, when the questioned soil phases are compared with collected reference samples to confirm the crime scene, vehicle route, etc. Alternatively, forecasting of an unknown location is required where contamination by soil may have occurred. These are in both cases complex analyses, in which the organic component of the sample is studied sepa-rately, possibly anthropogenic contamination and mineral material itself. Basic techniques are optical light microscopy in transmitted and reflected light, polarization, fluorescence, next are utilised SEM/EDS (WDS), XRF and FTIR. For the clay fraction, but also for other phases, the x-ray diffraction is imperative with applying conventional powder diffraction in transmission and reflected modes, scanning in a rotating capillary, and also micro x-ray diffraction, which allows to obtain a relevant structural record from the diameter around 0,1mm. Biological material frequently present in the traces is analysed separately, plant and animal relicts are analyzed, including microscopic shells and relics (e.g. group Dia-toms, etc.). Anthropogenic material (glass fragments, slag, construction materials, etc.) is analyzed separately by other techniques and may increase the probability measure of a match (hit) between traces and reference samples. Genetic methods that could compare both information from plant fragments and soil microorganisms are a big potential into the future.

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