Study On The Association Between Girls’ PAHs Exposure In The Early Development Of Youth And Puberty Timing

Objective: To study on the association between puberty timing of girls and polycyclic aromatic hydrocarbons(PAHs) exposure levels in Chongqing.Method: Application of high performance liquid chromatography(HPLC) to establish qualitative and quantitative detection methods for four kinds of PAHs metabolites in urine, including 1-hydroxy pyrene(1-OHP),2-hydroxy nathalene(2-OHNa), 2-hydroxy fluorene(2-OHFlu) and9-hydroxy phenanthrene(9-OHPh). According to the purposive sample method, four representative primary schools in Jiulongpo District,Chongqing, were selected and of which girls from grade one to four who have obtained written informed consent were recruited in our study.Questionnaire survey of the general information, physical examination of growth and development, as well as qualitative and quantitative detection of four kinds of PAHs metabolites in the urine by HPLC were carried out among objects.Result: The retention times of four kinds of PAHs metabolitesmeasured by HPLC were 2.34 min for 1-OHP, 2.06 min for 2-OHNa, 2.25 min for 2-OHFlu and 2.21 min for 9-OHPh. The working curves for them were: 1-OHP ^Y= 0.11+0.007 X, r=0.9997, 2-OHNa ^Y=0.23+0.087 X,r=0.9999, 2-OHFlu ^Y=0.21+0.01687 X, r=0.9998, 9-OHPh^Y=0.13+3.90 X, r=0.9989. The recovery rate of standard addition method of PAHs metabolites determination was over 80% and the detection limit was 0.1~50ng/ml, which can meet the requirements of the experiment. In the four primary schools, 737 girls between 8.81±1.23 years old were investigated, of which, 209 girls were classified into early puberty timing group while 528 girls were in the normal group. Urine PAHs metabolites test results showed that 4 kinds of PAHs metabolites were detected in all the 737 girls, including 1-OHP(0.01~4.77 ng/ml), 2-OHNa(0.15~50.00ng/ml), 2-OHFlu(0.06~12.59 ng/ml) and 9-OHPh(0.29~23.17ng/ml). The cause analysis of PAHs exposure showed that there were statistically significant differences between groups never/occasionally consumed smoked foods and frequently consumed smoked foods on1-OHP exposure concentration level(P < 0.05), significant differences between groups never/occasionally consumed fried foods and frequently consumed fried foods on 1-OHP and 9-OHPh exposure concentration level(P < 0.05), as well as significant differences between hair dye used group and non-used group on the exposure level of 9-OHPh(P < 0.05). The exposure levels of 2-OHFlu and 9-OHPh werestatistically different between early puberty timing group and the normal group(P<0.05).Conclusion:Based on the method of the previous research,this study established the HPLC detection methods for the four kinds of PAHs metabolites in urine. The experimental procedure was simple and the applicable scope was broad and easy to promote, which provided a high feasibility of detection means for the research of environmental endocrine disruptors in the future. All the girls in the study areas were exposure to PAHs at their early development of puberty. PAHs exposure may caused by frequently consumed smoked or fried foods, as well as frequently used hair dye. Exposure to PAHs might be one of the factors causing early puberty timing in girls.