Baby Teeth Reveal How Early Metal Exposure Shapes Developing Brains

How Can Baby Teeth Reveal Early-Life Chemical Exposures?

Primary teeth begin forming in utero and continue developing through early childhood, laying down fine incremental growth lines that capture the chemistry of a child's environment. Using laser ablation and mass spectrometry, researchers at the Icahn School of Medicine at Mount Sinai can read these layers to reconstruct week-by-week exposure to metals such as lead, manganese, arsenic, and zinc. This technique, pioneered by Mount Sinai's Senator Frank R. Lautenberg Environmental Health Sciences Laboratory, effectively turns a shed baby tooth into a time-stamped biomarker of prenatal and infant exposure.

The approach solves a long-standing problem in children's environmental health: by the time behavioral or cognitive issues appear in school-age children, the critical exposure window has long passed and traditional blood or urine measurements can no longer capture it. Baby teeth, naturally shed and easy to collect, preserve that history. Pairing the tooth data with later neuroimaging and neuropsychological testing allows scientists to draw lines between specific exposure windows and specific outcomes in the developing brain.

What Do Metal Exposures Do to the Developing Brain?

Lead is the best-documented neurotoxicant in pediatric environmental health. Decades of research, summarized by the World Health Organization and the US Centers for Disease Control and Prevention, show that there is no safe level of lead exposure in children, and that early exposure is associated with lower IQ, attention problems, and behavioral difficulties. Manganese is more complex: it is an essential nutrient at low doses but neurotoxic at high ones, and disruptions in either direction during development have been linked to cognitive and motor effects. Arsenic exposure, common in some groundwater and rice-based infant foods, has likewise been associated with neurodevelopmental impacts.

Combining tooth-based exposure timelines with MRI allows researchers to ask sharper questions: not just whether a child was exposed, but when, and what regions of the brain appear affected. Mount Sinai investigators and collaborators have reported associations between early-life metal exposure patterns and differences in cortical structure, white matter connectivity, and measures of executive function and mood. These findings reinforce the message that the fetal and early postnatal periods are uniquely vulnerable, and that public health efforts to reduce metal exposure pay dividends across the lifespan.

What Can Families and Policymakers Do to Reduce Risk?

Because the developing brain cannot be retroactively protected, prevention is the priority. Families can have homes built before 1978 inspected for lead paint and dust, test private well water for arsenic and manganese, and follow CDC and American Academy of Pediatrics guidance on limiting infant exposure to rice cereals and certain imported spices, cosmetics, and traditional remedies that have been linked to lead contamination. Adequate intake of calcium, iron, and zinc can reduce gastrointestinal absorption of lead, which is one reason pediatric nutrition is central to environmental health.

At the policy level, the Mount Sinai work strengthens the case for stricter regulation of lead in water infrastructure, consumer products, and industrial emissions, as well as continued surveillance for arsenic in food and water supplies. It also supports calls from the American Academy of Pediatrics and WHO to integrate environmental exposure histories into routine pediatric and prenatal care, so that clinicians can identify at-risk children early and connect families with mitigation resources.