Bone chemical composition changes in bird bones from laboratory exposure to saline lake conditions

摘要

The abundance of bird bones in archeological contexts of high salt is potentially impacted by salinization, which can affect bone preservation. We exposed wing elements (humeri, ulnae, and radii) of domestic chicken (Gallus gallus domesticus) to laboratory conditions simulating a saline lake substrate with overlaying saltwater for up to 32 weeks. Our analyses based on bone ashing and elemental concentration using ICP-OES are reported. The data provide useful taphonomic information regarding changes in bone mineral content, element concentrations, and element to phosphorus ratios of bird bones exposed to saline environments. Results showed that all exposed wing bones increased significantly in bone mineral content, which indicated that wing bones most likely became stronger. Overall, ionic concentrations of Ca2+, K+, Mg2+, Na+, P5+, Sr2+, and Si4+, except Fe3+, changed significantly among all wing bones with saline exposure. These changes in ion concentration took place in as little as 4 weeks. Element to phosphorus ratios provided insight into potential ionic substitutions between the bone and the saline substrate and solution exposure. The results from our study provide direct evidence that the chemical composition of bird bones deposited along saline lake shorelines quickly become altered.