Study on the Difference of Hydrogen and Oxygen Stable Isotope Ratios of Aksu, Lianyungang and Huai’an Urban Residents’ Hair

Stable isotope analysis has become one of the main trends in sourcing research. The isotopic ratios of carbon, hydrogen, oxygen, nitrogen, sulfur and other elements measured by isotope ratio mass spectrometry (IRMS) have been widely applied in geology, hydrology, agriculture, medical and environmental science. The stable isotope ratios of hydrogen and oxygen in atmospheric water vary significantly along geographical gradient. The differences in the stable isotope ratios of hydrogen and oxygen in water at different geographical locations can be reflected in human tissues, such as hair, nail, teeth, skeleton and so on, through biological metabolism. So the stable isotope ratios of hydrogen and oxygen in human hair (δ²H, δ¹⁸O) are related to the geographical location of their living cities. In this paper, the differences of δ²H and δ¹⁸O of urban residents’ hair living in 3 different cities, Aksu in the west and Lianyungang and Huai’an on the eastern coast in China were investigated. 79 hair samples of the residents living in the same city for the past 8 months were collected from the three cities, and 41 samples of their drinking water were also collected. The stable isotope ratios of hydrogen and oxygen of hair samples were determined by elemental analyzer-stable isotope ratio mass spectrometer (EA-IRMS). The data was analyzed by the Bayesian algorithm. Meanwhile, the hydrogen and oxygen stable isotope ratios of the drinking water in the three cities were determined by wavelength-scanning cavity ring-down spectrometer. The correlation of the stable isotope ratio of hydrogen and oxygen between the hair and drinking water was analyzed. The results showed that the stable isotope ratios of hydrogen and oxygen of Aksu, another two cities urban residents’ hair are significantly different (P<0.05), while there is no significant difference between Lianyungang and Huai’an urban residents’ hair (P<0.05). The results of Bayes discriminant analysis also showed that δ²H and δ¹⁸O of hair between Aksu and Lianyungang, Huai’an residents can be better classified, while another two cities are less effective. The discriminative accuracy of using δ²H and δ¹⁸O as discriminant factors is higher than that of using δ¹⁸O or δ²H separately. The stable isotope ratio of hydrogen and oxygen of hair were correlated with their drinking water (δ²H: r=0.933; δ¹⁸O: r=0.998).