Estimated Transfer of Perfluoroalkyl Substances (PFAS) from Maternal Serum to Breast Milk in Women Highly Exposed from Contaminated Drinking Water: A Study in the Ronneby Mother–Child Cohort

Abstract

Background: Infancy perfluoroalkyl substances (PFAS) exposure from breastfeeding is partially determined by the transfer efficiencies (TEs) of PFAS from maternal serum into breast milk. However, to our knowledge there are no studies of such TEs in highly exposed populations. Objectives: We estimated the TEs of PFAS from maternal serum into colostrum and breast milk in a cohort of women with a wide range of PFAS exposures. Methods: The Ronneby Mother–Child Cohort was established in 2015 after PFAS contamination was discovered in the public drinking water of Ronneby, Sweden. We measured seven PFAS in matched samples of maternal serum at delivery and colostrum and breast milk. We calculated the TE (in percentage) as the ratio of PFAS in colostrum or breast milk to serum multiplied by 100 and evaluated whether TEs varied by PFAS, lactation stage, or exposure level using a series of linear mixed-effects models with a random intercept for each woman. Results: This study included 126 mothers. PFAS associated with firefighting foams [i.e., perfluorohexane sulfonic acid (PFHxS) and perfluorooctane sulfonic acid (PFOS)] were substantially elevated in the serum, colostrum, and breast milk samples of highly exposed women in the cohort and showed strong correlation. PFHxS and PFOS also contributed the largest fraction of total PFAS on average in colostrum and breast milk. Median TEs varied from 0.9% to 4.3% and were higher for perfluoroalkyl carboxylic acids, including perfluorooctanoic acid, than perfluoroalkane sulfonic acids, including PFHxS and PFOS. TEs varied by exposure level, but there was not a consistent pattern in this variation. Discussion: PFAS concentrations in the colostrum and breast milk of highly exposed women were higher than the concentrations in low-exposed women, and TEs were of a similar magnitude across exposure categories. This implies that breastfeeding may be an important route of PFAS exposure for breastfeeding infants with highly exposed mothers, although the relative contribution of breastfeeding vs. prenatal transplacental transfer remains to be clarified. https://doi.org/10.1289/EHP11292

Per- and polyfluoroalkyl substances (PFAS) in grocery store foods: method optimization, occurrence, and exposure assessment

“…Few studies have investigated trophic transfer of PFAS, but studies have shown accumulation of PFBA and other PFAS in crickets after consumption of PFAS-impacted alfalfa, 120 and studies have also shown that PFAS, including short-chain homologues, are transferred to breast milk following exposure. 121–123…”

“…Few studies have investigated trophic transfer of PFAS, but studies have shown accumulation of PFBA and other PFAS in crickets aer consumption of PFAS-impacted alfalfa, 120 and studies have also shown that PFAS, including short-chain homologues, are transferred to breast milk following exposure. [121][122][123] To elucidate whether PFAS in produce were attributable to uptake or to PFAS applied or transferred to the outside of the plant (e.g. from pesticides or packaging) 124 fresh produce items were washed, dried, extracted and analyzed a second time.…”

Changes in Concentrations of Polyfluoroalkyl Substances in Human Milk Over Lactation Time and Effects of Maternal Exposure via Analysis of Matched Samples

“…53 The affinity of PFAS to proteins allows them to bind with serum proteins and be delivered to the mammary gland membrane or transported with phospholipids and regulated by fatty acid transport proteins in human milk. 19 The TE BM of legacy PFAS (PFOA, L-PFOS, PFNA, PFDA, L-PFHxS, and PFUdA) in Sweden and the US were determined to be in the range of 1.02%−2.72% (median) and 1%−4% (mean), 19,41 which are similar to the results obtained in this study (median 0.20%−2.14%, except 4:2 FTS and N-MeFOSAA with the highest TE BM values). Precursors or alternatives such as 4:2 FTS, and N-MeFOSAA have rarely been analyzed in human blood or human milk in previous studies.…”

“…Four studies conducted in Sweden and Korea reported higher PFOS concentrations in human milk collected 30 days postpartum compared with those in the colostrum, whereas four other studies reported a decreasing trend in PFOS concentrations. 19,20,24,25 Regarding PFHxS and PFNA, studies have reported elevated concentrations of these substances, along with lactation. However, these studies have only focused on traditional PFAS, which have been banned from production and are used in mostly developed countries following the listing of persistent organic pollutants under Annex B (restriction) by the Stockholm Convention since 2000.…”

“…However, these studies have only focused on traditional PFAS, which have been banned from production and are used in mostly developed countries following the listing of persistent organic pollutants under Annex B (restriction) by the Stockholm Convention since 2000. 19,24 China has issued formal regulations in 2023 to limit the production and use of PFOA and PFOS alongside their efforts to develop fluorine-based chemical industries. PFOA and PFOS accumulation is the highest and has been increasing in human milk in China from 2007 to 2020.…”