Objective: To develop amethod for simultaneous determination of four metabolites of polycyclic aromatic hydrocarbons( PAHs), and to study the association between puberty timing of girls and PAHs exposure levels in Chongqing.
Methods: Through purposeful sampling, questionnaire survey of the general information, physical examination of growth and development, collection of urine sample were carried out among1-4 grades of four primary school girls in a district of Chongqing. High performance liquid chromatography with mass spectrometry( HPLC-MS) was applied to qualitativelyand quantitatively detect four kinds of PAHs metabolites( 1-hydroxy pyrene( 1-OHP), 2-hydroxy beta( 2-OHNa), 2-hydroxy fluorene( 2-OHFlu) and 9-hydroxyl( 2-OHPh)) in the urine sample.
Results: The method had high correlation coefficients and the detection limits of the four metabolites were 0. 1 ng/mL. A total of 737 girls were investigated in this study, of which, 209 girls were classified into early puberty timing group and 528 girls were classified into normal group. Urine determination result showed that four kinds of PAHs metabolites were detected in all the 737 girls, and urinary concentration ranges of the four PAHs metabolites were as follows: 1-OHP( 0. 01-4. 77 ng/mL), 2-OHNa( 0. 15-50. 00 ng/mL), 2-OHFlu( 0. 06-12. 59 ng/mL) and 9-OHPh( 0. 29-23. 17ng/mL). The exposure levels of 2-OHFlu( Z =-1. 996) and 9-OHPh( Z =-3. 161)were statistically different between early puberty timing group and those in normal group( P < 0. 05). After control the variable of obesity, the exposure level of 9-OHPh( Z =-3. 012) in early group were still higher than normal group( P < 0. 05).
Conclusion: This determination method is suitable to simultaneously determine four PAHs metabolites in urine samples. All the girls in the study area have exposed to PAHs during their early stages of pubertal development, and exposure to PAHs might be one of the factors causing early puberty timing in girls.
Keywords: girl; high performance liquid chromatography; polycyclic aromatic hydrocarbons; puberty timing.