Effects of early exposure to toxic metals
May 19, 2026
Effects of early exposure to toxic metals
At a Glance
- Scientists found that toxic metal exposures during specific time windows increased the risk of brain and mental health symptoms a decade later.
- These results support the need for preventing excessive early life metal exposures and associated harms.
The body needs certain essential metals, such as zinc, magnesium, and manganese, to function properly. Yet having too much of these metals in the body can be harmful.
Other metals, such as lead, are toxic in any amount. Toxic amounts of metals can get into the body several ways, such as by eating or drinking, touching surfaces, or breathing in fumes or tobacco smoke. Infants and children are especially susceptible. The risks from exposure to potentially toxic metals increase during periods of rapid early brain development. Early-life exposure has been linked to mental health concerns later on.
A research team led by Drs. Manish Arora, Elza Rechtman, and Megan Horton at the Icahn School of Medicine at Mount Sinai Hospital studied how the timing of early exposure to metals affects the brain and behavior. To do this, they used naturally shed “baby” teeth to test for potentially toxic metal exposures over time based on their presence in the tooth layers. The results of the study were published in Science Advances on April 24, 2026.
Like tree rings, baby teeth develop layer by layer, with a new layer added about once a week. Metals in the body get incorporated into each new layer. Thus, each layer provides a record of metal exposures for a specific week during development.
The researchers examined baby teeth from 489 children aged 8 to 14. They measured levels of nine metals (lead, barium, copper, lithium, magnesium, manganese, tin, strontium, and zinc) in tooth layers from the second trimester of pregnancy until 40 weeks after birth.
The team assessed 395 of the children for symptoms relating to anxiety, depression, hyperactivity, and attention. Metal exposures during two critical time windows increased the risk for these symptoms. The first critical period was between the fourth and eighth weeks after birth. The second was between weeks 32 and 42 of age.
Additionally, 191 children were examined using magnetic resonance imaging (MRI). MRI results showed that excessive metal exposures during certain periods were more likely to impact brain structure and function, including how well brain regions communicated with each other. Exposures during the 19 weeks before birth were also associated with reduced connectivity.
The researchers note that the period 6 to 9 months after birth consistently emerged as a critical window for excessive metal exposures. This is also the period when infants transition to solid foods, and when they start crawling and exploring their environment. These activities may increase their chances of exposure.
The findings suggest that excessive metal exposures during key periods of brain development can have long-lasting effects. They also hint at the importance of policies to protect infants and pregnant women from metal exposure.
“This study shows that when exposure happens matters just as much as what the exposure is,” Horton says. “Our findings shift prevention from broad early-life exposure concerns to protecting children during specific high-risk windows.”
—by Laura Manella, Ph.D.
Related Links
- Early-life nutrition
- Lithium levels tied to Alzheimer’s disease and dementia
- Air pollution linked to dementia cases
- Preventing Lead Exposure
- Lead
- Smoking and Vaping
- Magnetic Resonance Imaging (MRI)
- Consumer Product Safety Commission
References
Fetal and postnatal metal metabolism-related changes in brain function are associated with childhood behavioral deficits. Rechtman E, Reichenberg A, Invernizzi A, Fleysher L, Rebello V, Oluyemi K, Rodriguez MA, Sather A, Torres-Olascoaga LA, Bautista-Arredondo LF, Martínez-Medina S, Lara-Estrada R, Gennings C, Téllez-Rojo MM, Wright RO, Arora M, Horton MK. Sci Adv. 2026 Apr 24;12(17):eadz1340. doi: 10.1126/sciadv.adz1340. Epub 2026 Apr 24. PMID: 42030382.
Funding
NIH’s National Institute of Environmental Health Sciences (NIEHS) and National Center for Advancing Translational Sciences (NCATS).
