Study Finds 90% of Preschoolers Exposed to Dozens of Industrial Chemicals

A newly released study published in Environmental Science & Technology found 90% of young children (ages 2-4) had measurable levels of 34 chemicals in the urine samples that were analyzed. Nine of these chemicals are not currently tracked in national health surveys. Researchers from multiple institutions analyzed samples from 201 children and tested for 111 chemicals.

The researchers also found 48 chemicals in more than half of the children and 96 chemicals in the urine samples of at least five children. The chemicals found include Phthalates and phthalate alternatives (found in plastics, toys, food packaging), Parabens (from cosmetics and lotions), Bisphenols (in plastics and can linings), Benzophenones (in sunscreen and plastics), Pesticides and organophosphate esters (OPEs used in flame retardants and packaging), Polycyclic aromatic hydrocarbons (PAHs from vehicle exhaust, grilling, smoke), Bactericides (in antibacterial soaps).

The authors note that several of these chemicals are endocrine disruptors that can disrupt hormones and may have negative impacts on brain and immune system development. “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,” lead author Jiwon Oh said. “This new study highlights the urgent need for expanded biomonitoring and stronger regulations to protect children from harmful exposures.”

Phthalates have been linked to autistic-like behaviors in children. A 2021 study concluded that prenatal exposure to phthalates is associated with autistic traits in young children. Early childhood phthalate exposure is linked to autistic traits in school-aged children, especially boys.

Dr. Catherine Karr, a co-author on the study, spoke with The HighWire and explained the implications of these findings. Dr. Karr said national health surveys do not routinely monitor many chemicals classified as phthalates. She stated that researchers continue to learn about the adverse health effects of these chemicals, particularly in children.

“Sometimes you’ll see chemicals changing in commerce because they’ve been regulated or banned because of concerns or restricted in some way,” Dr. Karr said. “So manufacturers may go ahead and replace one phthalate that’s been restricted or banned with a new phthalate that has not been as thoroughly studied or regulated. And I think there are concerns in the scientific community because these chemicals are in the same group for a reason, because they have similar chemical structures. Those chemical structures do influence their toxicity, and so often, we see what we call regrettable substitutions.”

Researchers found that younger children had higher chemical exposure than their older siblings. The primary explanation for this is that young children often put things in their mouths. Certain phthalates are restricted for use in children’s toys, but the Consumer Product Safety Commission clarifies that alternative phthalates can be substituted. The CPSC states it is the manufacturer’s responsibility to test any alternatives adequately and “must be confident that the product does not pose a risk of injury or illness under normal use or reasonably foreseeable misuse.”

Younger children receive the most exposure to these classes of chemicals, and they are also the age group most negatively impacted by this exposure.

Dr. Karr also brought attention to insecticides as a more concerning chemical class that children are frequently exposed to. Some specific insecticides are known to cause harm to children, and there is insufficient data for others.

“In this study, we did have a high detection of several insecticides, chemical metabolites – chemicals that are markers that children are exposed to insect killers,” Dr. Karr said. “They probably encounter [them] in the food supply as well as in their homes with pest control, flea collars on their pets; treatment products. [There are] all kinds of ways that kids are exposed to these types of pesticides. Some of those pesticides are ones that we’ve had concerns about for a long time, and we actually have a pretty good, strong evidence base of concerns that they affect the developing nervous system in children.”

“Many of our kids, these pesticides are designed to have nervous system toxicity for insects, and we have some of the similar mechanisms that they can affect in growing and developing brains,” Dr. Karr explained. “There’s a newer group of insecticides being used that are in a group called the neonicotinoids, and we have almost no kind of kid-health data on those.”

Neonicotinoids accounted for 25% of the global pesticide market in 2014, with 85% of that share being attributed to thiamethoxam, imidacloprid, and clothianidin. The EPA released a report in 2022 revealing that these three neonicotinoids likely cause harm to three-fourths of all endangered species and animals. The UK banned these insecticides in 2018 to protect the wild honeybee population. The neonicotinoid market in 2024 was $5.3 billion and is expected to be $9.1 billion in 2034.

Dr. Karr said monitoring programs like the National Health and Nutrition Examination Survey (NHANES) and the CDC’s biomonitoring program should be expanded to track health impacts from chemicals over time.

“It helps us in a couple of ways,” Dr. Karr explained. “Biomonitoring helps us to see which chemicals are most commonly seen in the population, including kids in vulnerable communities, and assess, do we have the health data that we need to feel like this is safe or not?”

Dr. Karr also explained the importance of investing in longitudinal studies to assess the long-term impacts of these chemicals. She said longitudinal studies help researchers track multiple chemical exposures over time rather than focusing on the effects of being exposed to a single chemical.

“What does it mean to have these mixture exposures, which is another thing I think that this study highlighted,” Dr. Karr explained. “Kids are not exposed to one thing at a time; there are multiple exposures happening at once.”

The HighWire reported earlier this week about a recent JAMA study that found American children (0-19) are 80% more likely to die than their peers in wealthy nations.