Human burials can affect soil elemental composition for millennia—analysis of necrosols from the Corded Ware Culture graveyard in the Czech Republic

How long decomposed buried human bodies affect soil elemental composition is so far not well-known. Using portable X-ray fluorescence spectrometry, we determined the elemental composition of sandy necrosols from a Corded Ware Culture (ca 2800–2500 BCE) graveyard, Chudeřin, Czech Republic. The elemental compositions of soils in the grave infills were studied and compared with arable and subsoil layers. After removal of the arable layer, infills of graves were identified by the black color in contrast with their reddish surroundings. The burials affected the content of elements even after more than 4500 years. Increased C contents compared with arable and subsoil layers were recorded only close to bones. The lowest P content was in grave infill, where soft tissues decomposed, because of P leaching. Therefore, increased P content in the infill of the prehistoric graves mentioned by previous authors is not a reliable indicator of soft tissue decomposition. In the acidic environment, P and Ca released from bones partly fixed in the grave infill ≤ 5 cm to bones. The high contents of P and Ca in bones and soils close to bones were a source of these elements for plants, indicated by a high density of fine roots. The highest contents of trace elements (Mn, Cu, As, and Pb) were in the arable layer because of recent disposition. The most reliable soft tissue decomposition indicator was an increased Zn content in the grave infill. The multi-elemental analyses of prehistoric necrosols were neglected so far and require further detailed research as the chemical signatures are well-preserved for millennia.