The importance of bone sample selection when using radiocarbon analysis in cases of unidentified human remains

The radiocarbon (¹⁴C) analysis of skeletonised human remains can provide vital information regarding the time since death. This study analysed the ¹⁴C content in both cortical and trabecular bone from the femur and rib of 18 human remains donated to the Australian Facility for Taphonomic Experimental Research. To determine the most appropriate bone to sample for ¹⁴C analysis when estimating the time since death, differences in turnover time between the bone types, and the difference between environmental ¹⁴C during the year of death (YOD) and the level of ¹⁴C found within the bone (i.e., the lag time) were examined. Overall, the average lag time for all donors was 25 years, with the cortical bone from femur samples providing the largest lag time (39 years) and the trabecular bone from rib samples containing the lowest level of ¹⁴C (most modern), with an average lag time of 13 years. The results of this study suggest that in cases of unidentified human remains, the analysis of trabecular bone from a rib may be preferred sample, as this bone contains the most recent ¹⁴C, and can provide an estimate of both the time since death, and a broad approximation of YOD.