Citation:

LaKind, J., M. Verner, R. Rogers, H. Goeden, D. Naiman, S. Marchitti, G. Lehmann, E. Hines, AND S. Fenton. Current breast milk PFAS levels in the US and Canada: After all this time why don’t we know more? International Society of Exposure Science (ISES), N/A, Virtual, August 30 - September 02, 2021.

Impact/Purpose:

Per- and polyfluoroalkyl substances (PFAS) are a large class of more than 9,000 structurally different compounds that have been used in industry and consumer products since the 1950s. They do not occur naturally, are widespread and persistent in the environment, and have been detected in people, wildlife, and fish all over the world. There is widespread exposure to PFAS, even a decade after one legacy PFAS, perfluorooctane sulfonate (PFOS), was taken off the market in the U.S. Despite twenty years of biomonitoring studies of these chemicals in both serum and urine, we have an extremely limited understanding of PFAS concentrations in breast milk of women in the US. The lack of robust information on PFAS concentrations in breast milk and the implications for both the breastfed infants and their families creates a dilemma for those who are trying to make informed decisions regarding the risks and benefits of breastfeeding. This information is also essential for public health agencies, including the EPA, for making recommendations to individuals, clinicians, and communities. In this work, we estimate concentrations of four PFAS (PFOA [perfluorooctanoic acid], PFOS, PFHxS [perfluorohexane sulfonate], PFNA [perfluorononanoic acid]) in breast milk in the US and Canada using milk/serum partitioning data in conjunction with serum PFAS concentrations and compare measured/estimated milk concentrations to public health screening values to illustrate the need for further research into this important topic.

Description:

Background. Despite twenty years of biomonitoring studies of per- and polyfluoroalkyl substances (PFAS) in both serum and urine, we have an extremely limited understanding of PFAS concentrations in breast milk of women from the US and Canada. The lack of robust information on PFAS concentrations in breast milk and the implications for both the breastfed infants and their families were brought to the forefront by communities impacted by PFAS contamination.  Objectives. To: 1) document published PFAS breast milk concentrations in the US and Canada; 2) estimate breast milk PFAS levels from maternal serum concentrations in national surveys and communities impacted by PFAS; and 3) compare measured/estimated milk PFAS concentrations to screening values. Methods. We identified three studies reporting breast milk concentrations in the US and Canada. To estimate breast milk PFAS concentrations, we multiplied publicly available serum concentrations (geometric mean and 95th percentile serum PFAS concentrations from two national surveys and six communities impacted by PFAS) by milk:serum partitioning ratios for four PFAS: perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and perfluorononanoic acid (PFNA) reported in the literature. Measured and estimated breast milk concentrations were compared to children’s drinking water screening values (Child Environmental Media Evaluation Guides (EMEGs)) developed by the Agency for Toxic Substances and Disease Registry (ATSDR).  Discussion. Geometric means of estimated breast milk concentrations ranged over approximately two orders of magnitude for the different surveys/communities. All geometric mean and mean estimated/measured breast milk PFOA and PFOS concentrations exceeded the Child EMEGs, sometimes by over two orders of magnitude. For PFHxS and PFNA, most measured breast milk levels were below the Child EMEGs, but for certain communities the estimated geometric mean milk concentrations were close to - or exceeded - them. Exceeding a Child EMEG does not necessarily mean that adverse public health effects will occur, but it indicates that the situation should be further evaluated. As breast milk may be the only source of hydration for the first months of life for many infants, a better understanding of environmental chemical transfer to - and concentrations in - an exceptional source of infant nutrition is critically important.

Record Details: