Dating human skeletal remains using 90Sr and 210Pb: Case studies

AbstractIn legal medicine, the post mortem interval (PMI) of interest covers the last 50 years. When only human skeletal remains are found, determining the PMI currently relies mostly on the experience of the forensic anthropologist, with few techniques available to help. Recently, several radiometric methods have been proposed to reveal PMI. For instance, 14C and 90Sr bomb pulse dating covers the last 60 years and give reliable PMI when teeth or bones are available. 232Th series dating has also been proposed but requires a large amount of bones. In addition, 210Pb dating is promising but is submitted to diagenesis and individual habits like smoking that must be handled carefully.Here we determine PMI on 29 cases of forensic interest using 90Sr bomb pulse. In 12 cases, 210Pb dating was added to narrow the PMI interval. In addition, anthropological investigations were carried out on 15 cases to confront anthropological expertise to the radiometric method. Results show that 10 of the 29 cases can be discarded as having no forensic interest (PMI>50years) based only on the 90Sr bomb pulse dating. For 10 other cases, the additional 210Pb dating restricts the PMI uncertainty to a few years. In 15 cases, anthropological investigations corroborate the radiometric PMI. This study also shows that diagenesis and inter-individual difference in radionuclide uptake represent the main sources of uncertainty in the PMI determination using radiometric methods