A groundbreaking national study reveals that U.S. preschoolers, children aged 2 to 4 years, are routinely exposed to a wide array of potentially harmful chemicals. This research, published in Environmental Science & Technology, tested for a broad spectrum of substances and found alarmingly widespread detection in young children across the country. The findings raise significant concerns among researchers because early childhood represents a critical and sensitive window for crucial brain and body development.
The study highlights that many of the chemicals identified are not consistently monitored in national health surveys. Their presence in young children at such high rates underscores potential risks that warrant urgent attention from public health officials, policymakers, and parents alike.
Alarming Findings on Widespread exposure
The research was a collaborative effort involving multiple institutions nationwide, coordinated with the Environmental influences on Child Health Outcomes (ECHO) program, which is supported by the National Institutes of Health (NIH). Researchers analyzed urine samples collected from 201 children aged 2 to 4 years residing in four different states: California, Georgia, New York, and Washington. They specifically screened for the presence of 111 different chemicals.
The results were striking:
96 chemicals were detected in samples from at least five children.
48 chemicals were found in detectable levels in over half of the participating children.
A concerning 34 chemicals were detected in more than 90% of the children tested.
Critically, among the chemicals detected in over 90% of children, nine are not currently tracked in major national health surveys like the National Health and Nutrition Examination Survey (NHANES). This indicates a significant gap in our current understanding of population-level exposure to these substances.
Deborah H. Bennett, the lead author and a professor at UC Davis, commented on the findings. She stated, “Our study shows that childhood exposure to potentially harmful chemicals is widespread. This is alarming because we know early childhood is a critical window for brain and body development.” Bennett added that many of these chemicals are known or suspected to interfere with vital biological functions, including hormones, brain development, and immune function.
What Chemicals Were Found?
The study focused on detecting exposure to common environmental chemicals encountered in daily life. These chemicals are prevalent in a vast range of consumer products and environmental sources. The specific classes of chemicals tested for included:
Phthalates and Phthalate Alternatives: Often used to make plastics more flexible (like in toys and food packaging) and found in personal care products and household items.
Parabens: Frequently used as preservatives in cosmetics, lotions, shampoos, and pharmaceuticals.
Bisphenols: Chemicals like BPA and its alternatives, found in hard plastic containers, the linings of food cans, and thermal paper receipts.
Benzophenones: Commonly included in sunscreens, cosmetics, and plastics to protect against UV light.
Pesticides: Chemicals used to control pests in agriculture and around homes.
Organophosphate Esters (OPEs): Used as flame retardants in furniture and building materials and as plasticizers in some food packaging.
Polycyclic Aromatic Hydrocarbons (PAHs): Byproducts created when organic matter is burned, found in vehicle exhaust, smoke (including tobacco), and grilled foods.
Bactericides: Agents designed to kill bacteria, often found in antibacterial soaps and some personal care products.
Why Are Young Children More Vulnerable?
Children are exposed to these environmental chemicals through seemingly innocuous everyday activities. These routes include eating contaminated food, drinking water, breathing indoor and outdoor air, and touching surfaces that harbor chemical residues.
Several factors make young children uniquely susceptible to higher exposures relative to their body weight. Frequent hand-to-mouth contact means they ingest chemicals picked up from surfaces more often. Playing close to the ground or floor exposes them directly to dust and particles where chemicals can accumulate. Additionally, children generally have higher intake rates of food, water, and air relative to their smaller body size compared to adults, leading to a higher dose of chemicals per pound of body weight.
Shifting Trends and Exposure Disparities
Beyond confirming widespread exposure, the researchers analyzed trends over the sample collection period, which spanned from 2010 to 2021. They observed some notable shifts in chemical levels.
Levels of certain “legacy” chemicals, such as triclosan, parabens, PAHs, and most phthalates, showed a decrease over the years. This downward trend might reflect the impact of past regulatory actions or industry shifts away from these specific substances.
However, levels of alternative plasticizers and some emerging pesticides were trending upwards. This included di-iso-nonyl-cyclohexane-1,2-dicarboxylic acid (DINCH), an alternative plasticizer, and newer pesticides like the neonicotinoid acetamiprid, various pyrethroid pesticides, and the herbicide 2,4-D. This suggests that as some chemicals are phased out, potentially less-studied alternatives are becoming more prevalent.
The study also identified significant disparities in chemical exposure levels among different groups of children:
Sibling Order: Firstborn children generally exhibited significantly lower overall chemical levels compared to their younger siblings.
Age: Younger children (age 2) often had higher chemical levels than children aged 3 or 4 years old.
Race and Ethnicity: Children from racial and ethnic minority groups were found to have higher levels of parabens, several phthalates, and PAHs. These findings point to potential environmental justice concerns, indicating that the burden of chemical exposure may not be evenly distributed across the population.
A unique aspect of this study involved comparing the chemical levels in the toddlers’ urine samples to samples previously collected from their mothers during pregnancy. The results showed that for several chemicals, the children had higher levels than their mothers did while pregnant. These included two specific phthalates, bisphenol S (often used as a replacement for BPA), and the pesticide biomarkers 3-PBA and trans-DCCA.
Why These Chemicals Matter: Risks to Developing Health
The presence of such a wide range of chemicals in developing preschoolers is particularly concerning given their known or suspected health effects. Researchers emphasize that exposure during early childhood, a period of rapid growth and neurological development, can have long-lasting consequences.
Specific chemicals detected in the study, such as certain pesticides, plasticizers (like phthalates and bisphenols), and flame retardants (OPEs), have been linked to potential long-term health issues. These include developmental delays, disruption of hormone systems (endocrine disruption), reproductive issues, and impaired immune function. Jiwon Oh, the first author of the study, highlighted these risks, stating that “Exposure to certain chemicals in early childhood — such as pesticides, plasticizers and flame retardants — has been linked to developmental delays, hormone disruption and other long-term health issues.”
Further research, like that reported by the Geneva Environment Network, strongly reinforces the link between plastic chemicals and serious health outcomes. Many chemicals found in plastics, including phthalates and bisphenols detected in this preschooler study, are known endocrine disruptors. Exposure to these has been associated with increased risks of infertility, obesity, diabetes, certain cancers (like prostate and breast), thyroid problems, and cardiovascular disease. The Geneva Environment Network report specifically notes the heightened susceptibility of vulnerable populations, particularly women and children, to these toxic chemicals, citing risks like prematurity, birth defects, neurodevelopmental impairment, and childhood cancer. The sheer volume of chemicals used in plastics, with thousands identified as concerning, underscores the scope of this challenge.
This principle – that early exposure to potentially harmful substances can have significant long-term impacts – is a recognized concern across different fields of health. For example, research into reducing opioid use in children after surgery, such as a project at UC Davis Health, is driven by evidence that earlier and greater exposure to opioids increases the likelihood of later misuse and addiction. While the chemicals differ greatly, the underlying principle holds: minimizing exposure to potentially harmful agents during critical developmental periods is crucial for lifelong health.
Moreover, the presence of pesticides raises another layer of concern. While the preschooler study focused on direct exposure, experts note that the widespread use of agricultural chemicals, including pesticides, can contribute to broader public health threats like antimicrobial resistance. As highlighted by UC Davis experts George Thompson and Angel Desai regarding antifungal resistance linked to pesticides, the development and use of chemicals in one sector (agriculture) can inadvertently impact human health outcomes (rendering medical treatments less effective). This points to the interconnectedness of environmental chemical exposure and human health, advocating for a comprehensive “One Health” approach to managing these substances.
Taking Action: Reducing Your Child’s Exposure
Given the widespread nature of chemical exposure, completely eliminating contact is challenging. However, there are practical steps parents and caregivers can take to help reduce children’s exposure to these potentially harmful substances in their daily lives.
Simple choices and practices can make a difference:
Choose Safer Products: Look for products labeled “phthalate-free,” “paraben-free,” and “fragrance-free.” The term “fragrance” can often mask the presence of phthalates. Opting for products with fewer ingredients or certifications can also help.
Be Mindful of Plastics: Try to avoid plastics labeled with recycling codes #3 (often contains phthalates), #6 (polystyrene), and #7 (other plastics, which can include bisphenols like BPA or BPS). Use glass, stainless steel, or ceramic containers when possible, especially for heating food or drinks.
Practice Good Hygiene: Wash hands frequently with plain soap and water, particularly before eating and after playing outdoors or touching surfaces in public places. This helps remove chemical residues children may have picked up.
Improve Air Quality: Ensure good ventilation in your home by opening windows when possible. Using high-efficiency particulate air (HEPA) filters in vacuums and air purifiers can help capture chemical-laden dust particles that settle indoors.
Limit Pesticide Exposure: Wash all produce thoroughly under running water, even if you plan to peel it. Consider choosing organic fruits and vegetables, which are grown without synthetic pesticides. Avoid using chemical pesticides or herbicides in and around your home and yard.
Clean Regularly: Dust and vacuum frequently, as chemicals from products and outdoor sources can accumulate in household dust. Use a damp cloth for dusting to trap particles effectively rather than just scattering them.
These steps, while not a guarantee against all exposure, can significantly lower a child’s overall chemical burden over time.
The Path Forward: Monitoring and Regulation
The researchers’ findings underscore an urgent need for expanded biomonitoring programs that specifically track chemical exposure in young children on a larger scale. The detection of numerous chemicals not currently included in national surveys highlights critical gaps in current surveillance efforts.
Beyond monitoring, the study supports calls for stronger regulations to protect vulnerable populations like preschoolers from harmful environmental exposures. Researchers like Jiwon Oh explicitly call for more robust regulatory measures. Given the links between chemical exposure and serious health outcomes, particularly during critical developmental periods, proactive regulatory action is essential to safeguard children’s long-term health and well-being. This aligns with broader calls, such as those related to plastics and health, emphasizing that addressing environmental contaminants is fundamentally about protecting human health, especially for future generations.
Frequently Asked Questions
What was the main finding of the new study on U.S. preschoolers?
The study found that U.S. children aged 2 to 4 years are routinely exposed to a broad range of potentially harmful chemicals. Testing urine samples from 201 children across four states revealed that 96 out of 111 tested chemicals were detected in at least five children, with 34 detected in over 90% of participants. Notably, nine chemicals found in over 90% of children are not currently tracked in national health surveys like NHANES, indicating widespread, poorly monitored exposure.
Why are young children uniquely vulnerable to chemical exposure?
Preschoolers are more vulnerable due to several behavioral and physiological factors. They frequently engage in hand-to-mouth contact, putting chemicals from surfaces into their bodies. They also play closer to the ground, where dust containing chemical residues accumulates. Additionally, their higher intake rates of air, food, and water relative to their smaller body weight mean they receive a higher dose of chemicals per kilogram compared to adults, increasing their risk from environmental contaminants.
What steps can parents take to reduce their child’s exposure to harmful chemicals?
While eliminating all exposure is difficult, parents can take practical steps. These include choosing personal care products and toys labeled “phthalate-free,” “paraben-free,” or “fragrance-free,” avoiding plastics with recycling codes #3, #6, and #7, washing hands and produce thoroughly, improving home ventilation, using HEPA filters, and cleaning regularly to reduce chemical-laden dust. These actions can help lower a child’s overall chemical burden.
Conclusion
The recent study on chemical exposure in U.S. preschoolers presents compelling evidence that young children face routine contact with a wide variety of potentially harmful substances. The widespread nature of this exposure, combined with the unique vulnerability of children during their critical developmental years, underscores a significant public health challenge. While individual actions can help mitigate exposure risks in the home, the findings also highlight the urgent need for expanded national monitoring and stronger regulatory frameworks to protect the health of current and future generations. Addressing this pervasive issue requires a concerted effort from researchers, regulators, and communities to ensure safer environments for our children.
