Historical trends in human serum levels of perfluorooctanoate and perfluorooctane sulfonate in Shenyang, China.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are widespread contaminants in the environment, as well as in wildlife and in humans. The PFOS and PFOA concentrations were determined in historical human serum samples collected in Shenyang, China, in 1987 (n=15), 1990 (n=33), 1999 (n=68) and 2002 (n=119). The serum donors were students, faculty members and university workers. Since the serum PFOA and PFOS levels did not follow a normal or log-normal distribution, a nonparametric method was applied to analyze the historical trends. For the total male and female subjects, the median level of serum PFOA increased significantly from 0.08 microg/l in 1987 to 4.3 microg/l in 2002 (p<0.05), while the median level of serum PFOS also increased significantly from 0.03 microg/l in 1987 to 22.4 microg/l in 2002 (p<0.05). Both the serum PFOA and PFOS levels continued to increase from 1999 to 2002, with remarkable increases observed in females: 6.3-fold increase for PFOA and 13-fold increase for PFOS. In 2002, serum PFOA and PFOS concentrations of female subjects have increased to 4.9 microg/l and 22.4 microg/l in median, respectively, which are comparable to those in U.S.A. and Japan. For male subjects, serum PFOA and PFOS concentrations (1.6 microg/l and 8.3 microg/l in median, respectively) are comparable to those in Italy. The data from this study indicate that females are likely to experience higher exposure to these chemicals.