An assessment of solubility profiling as a decontamination procedure for the 87Sr/86Sr analysis of archaeological human skeletal tissue

Sr-87/Sr-86 of archaeological skeletal tissues are increasingly used to reconstruct residential mobility and migration, but the post mortem preservation of biogenic Sr is often uncertain. Sample pre-treatment regimes, notably 'solubility profiling', have been used to remove diagenetic Sr prior to analysis, but doubts remain over their effectiveness. The investigation examines the effectiveness of solubility profiling by comparing the Sr content and Sr-87/Sr-86 composition of bone, dentine and enamel from two archaeological juveniles (Blackfriars, UK) before and after attempted decontamination. For both individuals leached samples of cortical bone and dentine had similar Sr-87/Sr-86 to those of soil leachates from the burial site, and are therefore thought to represent diagenetic Sr-87/Sr-86. For both individuals samples of treated dental enamel have Sr-87/Sr-86 considerably more or less radiogenic than the soil leachates and other tissues. These are considered representative of biogenic Sr, i.e. Sr acquired in vivo. In effect, solubility profiling should have resulted in Sr-87/Sr-86 that were similar for all 3 tissues types and close to those of the untreated enamel. Experimental results show that tooth enamel Sr-87/Sr-86 remained largely unaffected by solubility profiling, and the process did not significantly alter the final Sr-87/Sr-86 of either dentine or cortical bone. It is concluded that the technique was ineffective in facilitating the recovery of biogenic Sr from these tissues. (C) 2002 Elsevier Science Ltd. All rights reserved.