PFAAs in matched milk and serum from primipara women

The aim of the study was to assess the association between serum and milk levels of perfluoroalkyl acids (PFAAs) in humans. Individual milk and serum samples from fifty (50) primipara women in Uppsala, Sweden, were collected in 2004, 2007, 2009, and 2011. PFAAs were analysed in milk and serum using in-house validated methods and quality control protocols. PFOS, PFOA and PFHxS were detected in 98-100% of the milk and serum samples in the concentration order PFOS>PFHxS>PFOA. PFBuS, PFHpA, and PFDA were detected in 12-64% of the milk and serum samples. PFNA and PFUnDA were detected at high frequency but low levels in serum and were consequently less frequently detected in milk. PFOS and PFHxS showed a stronger correlation between serum and milk levels compared to PFOA. The regression slope with 95% confidence interval was calculated to assess the association between serum and milk levels. The level of PFOS in milk is 1.4 ± 0.25% of the corresponding maternal serum level. For PFHxS the interval is 1.4 ± 0.33% and for PFOA 2.6 ± 1.1%. The temporal trends (2004-2011) observed are similar in serum and milk