The Chalkboard: Recent EPA Children’s Health Research Updates
January 2025
EPA researchers work to advance the scientific understanding of the unique vulnerabilities children face from pollution and environmental contaminants. Their goal is to inform actions to protect children’s environmental health and support communities, parents, healthcare professionals, teachers, and other caregivers to provide safe places wherever children live, learn, and grow.
Below are a few recent highlights of how EPA research is advancing children’s environmental health.
Advancing the Science of Soil and Dust Ingestion Studies
Soil and dust ingestion are major routes of exposure for pollution and other environmental toxins, especially for children—who not only exhibit behaviors that increase the likelihood of ingesting soil and dust, but due to their relatively smaller size and still-developing bodies are also more vulnerable to potential adverse health impacts.
To advance the science of soil and dust ingestion studies, a team of EPA scientists and their partners conducted a novel meta-analysis of published studies of soil and dust ingestion in the North American region. Their work provides important insight into the three main types of ingestion studies (tracer, biokinetic, and activity pattern), and illustrates how statistical meta-analysis techniques can be used to estimate mean ingestion and confidence intervals. “Results can be used to better estimate population-based exposure and risk,” the authors conclude.
Source: Cohen, J., Hubbard, H., Özkaynak, H., Thomas, K., Phillips, L., & Tulve, N. (2024). Meta-analysis of soil and dust ingestion studies. Environmental Research, 261, 119649.
See the published study at: Meta-analysis of soil and dust ingestion studies - ScienceDirect
Exploring the Maternal and Development Toxicity of Next-generation Chemicals
Sparked by growing evidence of human and wildlife exposure to a new generation of polyfluoroalkyl substances (PFAS), commonly referred to as “forever chemicals,” a team of EPA scientists conducted one of the first studies to explore potential developmental toxicity of two such chemicals: PFO4DA and PFO5DoA.
The team exposed pregnant laboratory rats to the chemicals and then combined blood and liver RNA and small molecule metabolite analyses with dose-response modeling. Results revealed both genetic and metabolic impacts from the exposures in both the pregnant rats and their developing offspring. The work demonstrates potential developmental toxicity of the chemicals tested, especially to the developing offspring.
Source: Jackson, T. W., Lambright, C. S., Evans, N., Wehmas, L. C., MacMillan, D. K., Bangma, J., ... & Conley, J. M. (2024). Exploring maternal and developmental toxicity of perfluoroalkyl ether acids PFO4DA and PFO5DoA using hepatic transcriptomics and serum metabolomics. Science of The Total Environment, 953, 175978.
See the published results in: Exploring maternal and developmental toxicity of perfluoroalkyl ether acids PFO4DA and PFO5DoA using hepatic transcriptomics and serum metabolomics
Exploring Air Pollution's Impact of Children's Health
Since its establishment in 1970, EPA has targeted cleaner air as a top priority for protecting human health, especially for children who can suffer serious, even life-long impacts if exposed to unhealthy air during certain early lifestages, even those before birth. Two recent EPA studies explore the potential impacts of ozone exposure during fetal development.
Air Pollution and Male Reproductive Health and Development
What role does exposure to air pollution play in rising rates of male reproductive disorders? Because epidemiological studies have associated exposure to ozone with reduced sperm quality, EPA researchers conducted a study to explore if carefully timed exposures to ozone would reduce sperm motility and maturation in laboratory rats.
The team sought to determine if key periods of sperm maturation were particularly vulnerable to adverse impacts from ozone exposure. They also sought to identify components of maturing sperm on the molecular level, namely non-coding RNAs, that could be used to better understand the epidemiological evidence.
While the team did not find evidence of impaired sperm motility from their ozone exposures, they did identify a suite of non-coding RNAs associated with sperm motility, warranting further investigation into the role they may play in sperm maturity, and how they might be used as biomarkers.
Source: Chorley, B. N., Klinefelter, G. R., Nelson, G. M., Strader, L. F., Nguyen, H. H., Schladweiler, M. C., ... & Miller, C. N. (2024). Episodic ozone exposure in Long-Evans rats has limited effects on cauda sperm motility and non-coding RNA populations. Reproductive Toxicology, 108631.
See the published study at: Episodic ozone exposure in Long-Evans rats has limited effects on cauda sperm motility and non-coding RNA populations
Ozone Exposure: Developmental Effects in Male and Female Rats
In assessing chemical risks during pregnancy, EPA researchers learned that ozone exposure during pregnancy may impact fetal growth. Researchers next investigated lung health and development in offspring from rats that had been exposed during pregnancy.
The team studied exposure at varying sensitive windows of exposure, including early gestation and adolescence, in both male and female offspring. They found that lung development in females was more significantly impacted by gestational exposure, whereas the males were more affected by adolescent exposure, especially those from exposed rat mothers. Importantly, the study extends connections between maternal exposure to air pollutants and effects on fetal growth to also include atypical lung development, as well as a distinction between results based on sex. These connections add to our understanding of how early life environmental exposures may contribute to pulmonary disease later in life.
Source: Dye, J. A., Nguyen, H. H., Stewart, E. J., Schladweiler, M. C. J., & Miller, C. N. (2024). Sex Differences in Impacts of Early Gestational and Peri-Adolescent Ozone Exposure on Lung Development in Rats: Implications for Later Life Disease in Humans. The American Journal of Pathology 194(9), 1636-1663.
Learn more from the published study at: Sex Differences in Impacts of Early Gestational and Peri-Adolescent Ozone Exposure on Lung Development in Rats: Implications for Later Life Disease in Humans
Learn more about EPA Lead Research to Protect Children's Health.
Virtual Embryo: Advancing Developmental Toxicology
EPA researchers are leading efforts to advance high-tech, computer- and robot-aided technologies and methods for assessing chemical risks. These “New Approaches and Methods” (NAMS) aim to usher in a new generation of toxicology studies that assess chemicals in far faster, more efficient, and less expensive ways than is currently available through tradition, animal-based testing. One area of this work that is particularly promising for children's environmental health is the development of a virtual embryo, which can be used to screen chemicals for their potential to disrupt healthy growth during some of the most vulnerable stages of early life.
A team from the Agency’s Center for Computational Toxicology and partners recently published an important milestone in the development of those efforts: engineering a model simulating key parts of embryonic development. “Here, we engineered a fully computable model of the embryonic disc in the CompuCell3D.org modeling environment to simulate epithelial-mesenchymal transition (EMT) of epiblast cells and self-organization of mesodermal domains (chordamesoderm, paraxial, lateral plate, posterior/extraembryonic),” the authors explain.
The new model advances ongoing efforts to develop a “virtual embryo” model that integrates chemical data with the complex biological systems of development to improve testing. When complete, such a model would greatly expand the capability of researchers to run developmental toxicological experiments.
Source: Barham, K., Spencer, R., Baker, N. C., & Knudsen, T. B. (2024). Engineering a computable epiblast for in silico modeling of developmental toxicity. Reproductive Toxicology, 108625.
See the published study at: Engineering a computable epiblast for in silico modeling of developmental toxicity.