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Perfluoroalkyl acids in the serum and milk of breastfeeding North Carolina women
Citation:
von Ehrenstein, O. S., E. P. HINES, K. Kato, Z. Kuklenyik, A. M. Calafat, AND S. E. FENTON. Perfluoroalkyl acids in the serum and milk of breastfeeding North Carolina women. Presented at ISEA / ISEE, Pasadena, CA, October 12 - 16, 2008.
Impact/Purpose:
Presentation @ 2008 ISEA / ISEE Annual Meeting
Description:
Perfluoroalkyl acids (PFAAs) comprise a group of man-made persistent environmental compounds. They are widely used in consumer products such as food packaging material, non-stick cookware and cleaning agents, and have been detected in drinking water. Certain PFAAs tend to bioaccumulate and have been shown to be widespread in wildlife and humans although exposure data are limited. High doses of two of the most widely distributed PFAAs – perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) - have shown developmental toxicity in laboratory animals when used at doses 100 to 500 times that in human serum. NHANES II serum data, which looks at the US population, shows than mean PFOS and PFOA levels are 20.7 and 3.9 ng/mL, respectively. Human biomonitoring and laboratory animal experiments indicate that certain PFAAs have the ability to transfer to milk although concentrations are thought to be lower in milk than in serum. Methods: The US EPA conducted a pilot study entitled Methods Advancement in Milk Analysis (MAMA) including 34 breastfeeding North Carolina women between 18 and 38 years of age. The women donated milk and serum samples at 2-7 weeks and 3-4 months postpartum. Automated solid-phase extraction coupled to reversed-phase high performance liquid chromatography-tandem mass spectrometry was used to determine serum and milk concentrations of seven PFAAs: perfluorooctane sulfonamide, 2-(N-ethyl-perfluorooctane sulfonamido) acetate, 2-(N-methyl-perfluorooctane sulfonamido) acetate, perfluorohexane sulfonate, perfluorononanoate, PFOS, and PFOA. During the first visit, a questionnaire was administered asking about potential dietary and other exposure routes as well as socio-demographic characteristics, including the duration of residence in North Carolina. Results: Of the 7 PFAA compounds, all except one were detected in a majority of women’s sera with PFOS and PFOA detected in greater than 98% of samples. Mean concentrations (ng/mL) at the two visits were 21.9 (SD: 8.3); 18.8 (8.3) for PFOS, and 3.9 (2.0); 3.0 (1.2) for PFOA, respectively. Neither PFOA nor PFOS were detected in milk. Women who had lived in North Carolina for 10 years or more had significantly higher serum concentrations (ng/mL) compared to those living in North Carolina less than 10 years at 2 – 7 weeks postpartum for PFOS: 26.6 (SD: 12.3) vs. 16.7 (6.7), p-value 0.007, and for PFOA: 4.7 (2.2) vs. 3.0 (1.4), p-value 0.01(t-test). Similar significant differences were seen at 3 – 4 months postpartum. Conclusions: In this pilot study, concentrations of PFOS and PFOA were below the limit of detection in breastmilk, although they were detectable in nearly all serum samples collected. Although the number of participants in this pilot study is small (n=34 and n=30, visits 1 and 2, respectively), there is an indication that living in North Carolina for a prolonged time period might be related to increased serum concentrations of certain PFAAs. PFAA exposure in lactating North Carolina women will be further explored in the upcoming National Children’s Study, which provided partial funding for this pilot project. (This abstract does not necessarily reflect CDC, EPA or NIH policy.)