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Bogdan et al. J Environ Expo Assess 2024;3:14 https://dx.doi.org/10.20517/jeea.2024.08 Page 3 of 13

In the 2017 HBGV, MDH’s TK model evaluated two exposure scenarios: an infant exposed to PFOA from
formula reconstituted with contaminated water, and an infant exposed to PFOA via breastfeeding from a
[15]
mother who drinks contaminated water . Breastfed infants had peak PFOA serum levels that were more
[15]
than four times higher than formula-fed infants . However, the formula-fed infant evaluation assumed
that the only source of PFOA in reconstituted formula was contaminated water. This was because little was
- and continues to be - known about potential PFAS contamination in powdered formula itself [9,21] . The
overall lack of data about PFAS in infant formula results in the possibility of underestimating PFAS
exposures for formula-fed infants.

To examine this, we measured the concentrations of 10 PFAS in 17 different powdered formulas sold in the
United States. Next, using our recently updated TK model, we estimated serum PFOS concentration curves
over the first year of life for several exposure scenarios, including different fluid intake rates, formula
reconstituted with uncontaminated and contaminated water, and with and without placental transfer while
providing risk context for each scenario.

MATERIALS AND METHODS
Formula selection
Seventeen different types of powdered infant formulas were selected for analysis. Ten were included based
on data from MDH’s Women, Infants, & Children (WIC) program. The WIC program is a nutrition and
breastfeeding program that helps pregnant women and young families with nutrition education and
[22]
counseling, nutritious food, and referrals to social services . WIC participants are one of the largest groups
of purchasers of infant formula, and only certain formulas are available through WIC at a given time. We
submitted a public data request to the WIC program for purchasing statistics for the most popular contract
(i.e., standard, routine formulas) and medical (i.e., requires a documented medical diagnosis) formulas
available through their program from December 2021 to January 2023. These formulas represent some of
the most widely used formulas in Minnesota. Additional selections were made to increase coverage of
available formula types. The 17 formulas can be characterized in several ways:

● WIC (7 contract, 3 medical), non-WIC (7)
● Dairy (12), Soy (4), Amino acid (1)
● Organic (3), Non-organic (14)
● Dietary need
○ Standard/added rice (for spit-up) (6)
○ Lactose sensitivity (6)
○ Protein sensitivity (1)
○ Premature infants (2)
○ Hypoallergenic (2)

A complete list of formulas tested is shown in Supplementary Table 1.

Sample preparation and analysis
[23]
Sample preparation and analysis are slightly modified from Criswell et al. . Triplicate samples of powdered
formula were weighed on a high-precision balance (Sartorius BCA324I-1S) and reconstituted in ultrapure
water to a 20% weight/volume stock solution. The analysis of PFAS in reconstituted formula was performed
through protein precipitation followed by centrifugation, concentration, and analysis using liquid
chromatography tandem-mass spectrometry (LC/MS/MS). A stable isotope-labeled internal standard
solution and cold acetonitrile were added to a 400 µL aliquot of reconstituted formula in microcentrifuge