A new laboratory-based method to experimentally induce diagenetic modifications in human bone tissue using archaeological gravesoils

Abstract

The conditions of the burial environment trigger microstructural modifications and physical-chemical changes in the bone, such as chemical dissolution, increase of crystallinity, chemical exchanges, collagen degradation and changes in porosity, hence to reproduce these patterns is a challenging task. This work presents a new method to accelerate the diagenetic processes in the laboratory. Artificial aging is obtained by immersion at 80°C in “enriched” solutions derived from the leaching of gravesoils, maintaining the same pH, for 1 month, on modern bones collected from an autopsy. Two distinct solutions from two graves of the necropolis of Travo (IT) (7th–8th century AD) were adopted. The induced damage patterns, on the bone microstructure and the organo-mineral fraction, have been compared with those observed on buried skeletal elements from the same graves, by providing a multi-analytical approach (BSE-SEM, EMPA, FT-IR, MP-AES). Bioapatite parameters, such as crystallinity index and Ca/P molar ratio, evolved similarly and, in some cases, reached the same values of buried bones. Conversely, in the absence of microbial activity, the organic fraction better survived the artificial aging. For the same reason, the porosity due to bioerosion was absent in the artificially aged samples, whereas the biological pores and the post-mortem fractures exhibited the same histomorphology. It is believed that the opportunity of reproducing the diagenetic changes by replicating the chemical environment of the burial site at the laboratory scale is of great interest to forensic science and archaeology (e.g., to reconstruct the burial environment).