Stable isotope relationships between apatite phosphate (δ O), structural carbonate (δ O, δ C), and collagen (δ H, δ C, δ N, δ S) in modern human dentine.

RATIONALE

The use of multi-isotopic analysis (δ H, δ C, δ N, δ O, and δ S values) of modern human body tissues for provenancing of unknown individuals in forensics is increasing. Tooth dentine develops during childhood and adolescence, therefore providing geographical information from that period of life. Tooth apatite δ O values are commonly used for the reconstruction of drinking water values, and H-C-N-S isotope ratios in collagen supply additional information about the composition of diet. We tested if dentine collagen δ H values provide similar information to apatite δ O values with a proof-of-concept study.

METHODS

Tooth samples were taken from modern-day individuals born in different regions of the world. Apatite and collagen were prepared from dentine. Stable isotope analyses were performed on apatite phosphate oxygen (δ O ); oxygen and carbon of the structural carbonate (δ O , δ C ); and hydrogen, carbon, nitrogen, and sulfur of the collagen (δ H δ C , δ N, δ S).

RESULTS

δ O , δ O , and δ H values are highly correlated in modern human dentine. There are significant relationships of δ O values in the apatite fraction and δ H values in the collagen fraction with local δ O and δ H precipitation values, respectively. Pearson correlation coefficients indicate no direct relationship between δ N values and the isotope ratios of any other element. Weak relationships exist between collagen δ S values and δ O or δ O values.

CONCLUSIONS

The highly significant correlation of δ O , δ O , and δ H values in the modern human dentine implies that measurement of δ H values in collagen or δ O values in bioapatite will provide reliable information about the climate at the person's whereabouts.