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Bogdan et al. J Environ Expo Assess 2024;3:14 https://dx.doi.org/10.20517/jeea.2024.08 Page 5 of 13

Table 1. List of PFAS analytes and associated method reporting levels
CASRN DTXSID PFAS LOQ (ng/L)
307-24-4 DTXSID3031862 Perfluorohexanoic acid PFHxA 25
375-85-9 DTXSID1037303 Perfluoroheptanoic acid PFHpA 25
335-67-1 DTXSID8031865 Perfluorooctanoic acid PFOA 10
375-95-1 DTXSID8031863 Perfluorononanoic acid PFNA 10
335-76-2 DTXSID3031860 Perfluorodecanoic acid PFDA 10
2058-94-8 DTXSID8047553 Perfluoroundecanoic acid PFUnA 25
375-73-5 DTXSID5030030 Perfluorobutanesulfonic acid PFBS 10
355-46-4 DTXSID7040150 Perfluorohexanesulfonic acid PFHxS 10
1763-23-1 DTXSID3031864 Perfluorooctanesulfonic acid PFOS 10
754-91-6 DTXSID3038939 Perfluorooctanesulfonamide PFOSA 10

CASRN: Chemical Abstracts Service registration number; DTXSID: Distributed Structure-Searchable Toxicity Substance Identifier; LOQ: limit of
quantitation; PFHxA: perfluorohexanoic acid; PFHpA: perfluoroheptanoic acid; PFOA: perfluorooctanoic acid; PFNA: perfluorononanoic acid;
PFDA: perfluorodecanoic acid; PFUnA: perfluoroundecanoic acid; PFBS: perfluorobutanesulfonic acid; PFHxS: perfluorohexanesulfonic acid; PFOS:
perfluorooctanesulfonic acid; PFOSA: perfluorooctanesulfonamide.

Toxicokinetic modeling and risk assessment
PFOS is bioaccumulative, and the serum concentration rather than intake is the best measure of
exposure [15,19] . MDH previously published a TK model that calculates daily serum concentrations of
[15]
bioaccumulative PFAS over a simulated lifetime and which has been used in the derivation of Minnesota
[14]
health-based guidance values for several bioaccumulative PFAS, including PFOS . The model evaluates
two exposure scenarios: an infant exposed to reconstituted formula prepared with contaminated water, and
a breastfed infant whose mother consumed (and continues to consume) contaminated drinking water.
MDH has updated the TK model and used it in the derivation of the most recent health-based guidance
[20]
[18]
values for PFOA and PFOS . The updated version of the TK model and the reconstituted formula
[19]
scenario were used in this analysis. A list of the TK parameters used in the updated model and the sources
of the values are presented in Table 2.

RESULTS AND DISCUSSION
PFAS detections in infant formulas
No PFAS were detected above the LOQs in 16 of 17 infant formulas tested. In the one formula that had a
detection, a dairy-based formula, only PFOS was detected in triplicate samples [Table 3] of a 20% weight/
volume solution at an average concentration of 12 ng/L (standard deviation = 0.6), with a calculated
concentration in formula reconstituted per label instructions of 8.9 ng/L. PFOS is one of the few PFAS
previously determined to accumulate in cow’s milk [27-29] .

Risk assessment of PFOS exposure from infant formula
Exposure to PFOS from formula alone
To evaluate the impact of formula alone on the serum concentration during an infant’s first year of life, we
modeled an infant exclusively consuming reconstituted formula with a PFOS concentration of 8.9 ng/L with
either a mean or 95th percentile formula intake rate from EPA’s Exposure Factors Handbook [Figure 1].
[25]
These scenarios assume the infant has no other exposure to PFOS, e.g., no placental transfer, no PFOS in
the water used to reconstitute the formula, no household exposures, etc.

Since there is no placental transfer considered in this scenario, the serum PFOS concentration at birth in
these model runs are zero. Over the course of the first year, serum PFOS concentrations for an infant would
increase to 0.33 ng/mL (mean fluid intake) or 0.66 ng/mL (95th percentile fluid intake).