Geological aspects of decomposition of corpses in mass graves from WW1 and 2, located in SE Poland

The investigations were carried out to identify processes and mineral products in the diversified subsoil sediments of mass graves from WW1 (four graves) and 2 (five graves) and their surroundings, as well as the relations between the development of sediments within the mass graves and the scale of migration of the products of corpse decomposition. The author studied the role of iron compounds and clay minerals in the decomposition of human corpses buried in mass graves, followed by the migration of selected elements. In particular, he concentrated on the list of elements found in the diversified sediments of nine mass graves from SE Poland and to their relationship with phosphorus compounds. The methods applied included scanning electron microscopy (SEM) and optical polarizing microscopy. Samples were collected from various depths in trenches and holes dug in the vicinity of the graves, the sediments from the burial horizon and, when possible, the sediments underlying the grave (studied downslope). Detected phosphorus occurs as a weakly crystalline compound in silt-rich sediments with relatively stable water conditions. In silt-rich sediments with relatively stable moisture content, phosphorus occurs as a weakly crystalline compound. More stable aggregates of decomposition products have been found on quartz grains covered with clay-ferruginous rims. Fragments of human soft tissue were found only in those graves from WW2. There is no link between the spectrum of elements in the sediments of the graves and the period of burials. The decomposition products that form depend primarily on the type of sediments in which the mass graves were dug and, secondarily, although related, on the moisture content of the sediments. It has been found that stabilization of decomposition products in situ is related to the presence of iron compounds and clay minerals, particularly in finer-grained, aleuritic–pelitic sediments.