Human Hair And Nail As Bioindicator Of Exposure To Perfluoroalkyl Acids

Perfluoroalkyl acids (PFAAs) are a series of emerging persistent organic pollutants receiving increasing attention recently. Their numerous uses and unique physical and chemical characteristics have posed human to a widely and continuous PFAAs exposure at low dose. PFAAs have been detected in general population living all over the world, and the potential adverse effects of PFAAs on human health have attracted an increasing concern of both the public and the scientists in the field of environmental science.Hair and nail analysis have been widely employed in assessing trace element deficiency and disease diagnosis, and began to be used for the exposure assessment of hydrophobic persistent organic pollutants, e.g. DDT. Compared with the blood samples, hair and nail are advantageous in non-invasive collection, easy collection, store and transportation, and being able of reflecting long term exposure. In this study, the method of PFAAs analysis in hair was developed at first. Then, a defined PFOA/PFNA/PFOS exposure in rats was conducted, and the distribution of PFOA/PFNA/PFOS in rat hair, serum, main tissues, and the correlation were evaluated. At last, human hair and nail were used to evaluate PFAAs exposure of people at different ages in Dalian and the undergraduates in other5representative cities in china.The alkaline digestion and ion pair extraction method was employed in PFAAs hair analysis. Ten PFAAs including PFOA, PFNA and PFOS were detected, with the method limit of quantification ranging from0.1to0.4ng/g, and recoveries between75%and99%. After subchronic exposure, PFOA/PFNA/PFOS were detected in all the rats hair samples in a dose-dependent manner. In addition, significant positive correlations were observed between the hair PFAAs levels and the PFAAs levels in serum and other tissues. The results indicate that hair is capable of reflect PFAAs exposure accurately. The correlations between hair PFAAs concentration and gender, exposure doses, serum, tissues in rats could have some inspiration for human exposure. When using hair as bioindicator of PFAAs exposure for people at different ages>20in Dalian, seven PFAAs were detected in hair samples, where the detection frequency are100%, except for PFOA. PFBS, PFOA, PFHxS, and PFOS were the main contaminants. The tatal PFAAs concentrations in hair samples ranged from33.7to50.3ng/g. Hair, serum and nails PFAAs concentrations were higher in male than the female. In addition, significant positive correlations were observed between hair, serum and nails PFAAs. The PFAAs concentrations in nails of college students in five cities showed some difference in gender and geographical distribution. Comparing the results with our previous study of another five cities in china, the total PFAAs concentrations decreased in the order of Guiyang>Qingdao>Xi’an>Lanzhou>Chongqing>Wulumuqi>Guangzhou>Hangzhou>Harbin, ranging from6.95to27.8ng/g. PFNA was the dominating PFAA in nail samples, indicating more attention should be given on the health risk of PFNA exposure. The results showed that hair and nail could be employed as an accurate, non-invasive bioindicator of human PFAAs exposure.