The Chalkboard: Recent EPA Children’s Health Research Updates
September/October 2025
Studying pathways for PFAS exposure and potential developmental effects
PFAS are chemicals that have been used in industry and consumer products for over 80 years. They are known as “forever chemicals” because some PFAS do not break down easily and can stay in the environment for a long time. Because of their widespread use and their persistence in the environment, certain PFAS have been found in the blood of people and animals all over the world. There are thousands of different PFAS, but some are more common and have been studied more than others. People are mainly exposed to PFAS through oral routes, such as drinking water that has been contaminated with PFAS without realizing it. Exposure to PFAS has been linked to adverse health effects in children, including delays in development, decreased birth weight, early puberty, and behavioral changes. Recent laboratory studies on animals and reviews of existing research by EPA scientists have helped us learn more about the exposure to PFAS in pregnant women and children.
Using fish to evaluate PFAS effects on development
Points of departure (POD) estimates are important in understanding the risk of chemical exposure. They are used to identify the concentrations at which chemicals cause low or no negative health effects. Thus, if someone is exposed to a chemical at or below these concentrations, they’re less likely to experience harmful health effects. EPA scientists used developing zebrafish to evaluate the chemical-specific effects of three specific PFAS: perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorohexanesulfonic acid (PFHxS). They looked at how these chemicals affected the zebrafish at different times and for different durations using transcriptomics. Transcriptomics provides a snapshot of all the ribonucleic acid (RNA) in cell. RNA can be thought of as instructions for cells in the body - they help tell the story of what the body is doing and these instructions may change when the body is exposed to chemicals. The data collected was used to estimate transcriptomics-based point of departure (tPODs). The results showed that in developing zebrafish PFAS tPODs are generally protective of adverse outcomes from short-term PFAS exposures and that these protective effects did not change much regardless of when the exposure started or how long it lasted. Research in the field has suggested zebrafish are a possible alternative model for assessing effects of PFAS on developing organisms, including humans
Evaluating the influence of food consumption on PFAS concentration in pregnant women
EPA investigators studied how different foods might affect the levels of PFAS in the blood of pregnant women. They used data from the National Children's Study Initial Vanguard pilot study, a large-scale, ~5,000 participant study aimed to investigate environmental influences on child health and development. Researchers analyzed blood samples from 374 women to look for PFAS including perfluorooctanoic acid (PFOA), perfluorooctanesulfonate (PFOS), perfluorononanoic acid (PFNA), perfluorohexanesulfonate (PFHxS), perfluorodecanoic acid (PFDA), and 2-(N-methyl-perfluorooctane sulfonamido acetate (Me-PFOSA-AcOH). The women in the study were also asked about their diets.
Results showed that women in the study who ate more shellfish and seafood had significantly higher concentrations of PFNA and PFDA in their blood. In addition, consumption of potatoes, soft drinks, beef mixtures, bagels, English muffins, and cold cereals was associated with increased levels of PFHxS. On the other hand, pregnant woman in the study who ate more cereals and grains had lower levels of PFDA and PFOS, while PFNA and PFDA were lower in women who consumed more dairy. These results suggest that what women eat during pregnancy may influence the levels of specific PFAS chemicals in their blood.
Mapping pathways for dietary exposure to PFAS
In a study looking at dietary exposure to PFAS, EPA investigators reviewed results from numerous peer-reviewed articles on PFAS to identify and map important pathways that may expose us to PFAS through the food we eat. Information was extracted from the literature on what PFAS have been measured in which foods, whether people are exposed to PFAS in the food that they consume, and how the food is contaminated with PFAS. Their research confirmed that PFAS are found in various foods and that eating certain foods can increase PFAS exposure. This study also identified important gaps in the current literature on how PFAS might be present in agricultural processing and how PFAS might transfer during food storage and preparation. Addressing these gaps in knowledge could help inform actions to reduce potential health impacts associated with PFAS exposure through diet.
Analyzing legacy PFAS effects on birth weight
Perfluorooctane sulfonic acid (PFOS) is a legacy PFAS, that while banned in some countries, is still found in both the environment and in nearly all humans given how long it can persist. Using systematic review and statistical approaches, EPA investigators examined differences in human birth weight in relation to indicators of PFOS exposure. They reviewed 53 relevant studies and found that as indicators of PFOS exposure (using blood biomarkers) increased birth weight subsequently decreased. This study suggests the potential risk of developmental health effects related to PFOS remain even if they are not currently in use.
Learn more about EPA research on PFAS
Sources:
- Shankar P, Hazemi M, Mattingly K, See MJ, Bell ME, Ellman ME, Cavallin JE, Lasee S, Blackwell BR, Vliet SM, Biales AD, Lalone CA, Villeneuve DL. Comparison of transcriptomic points of departure with apical endpoints in developing zebrafish exposed to PFOS, PFOA, or PFHxS. Toxicol Sci. 2025 Jul 1;206(1):134-146. doi: 10.1093/toxsci/kfaf047. PMID: 40175316.
- DeLuca NM, Thomas K, Luben TJ, Melnyk LJ. Associations between self-reported consumption of foods and serum PFAS concentrations in a sample of pregnant women in the United States. Environ Res. 2025 Jul 1;276:121461. doi: 10.1016/j.envres.2025.121461. Epub 2025 Mar 22. PMID: 40122495.
- Melnyk LJ, Holder C, Luh J, Thomas K, Cohen Hubal EA. Evidence mapping and scoping review of pathways for potential dietary exposure to per- and poly-fluoroalkyl substances (PFAS). Environ Sci Process Impacts. 2025 Aug 13;27(8):2452-2463. doi: 10.1039/d4em00696h. PMID: 40601363.
- Wright JM, Rappazzo KM, Ru H, Lee AL, Dzierlenga MW, Bateson TF, Radke EG. Birth weight in relation to maternal and neonatal biomarker concentration of perfluorooctane sulfonic acid: a meta-analysis and meta-regression from a systematic review. J Expo Sci Environ Epidemiol. 2025 Aug 22. doi: 10.1038/s41370-025-00798-8. Epub ahead of print. PMID: 40847085.
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