• Posted July 10, 2025

Lead Exposure Can Harm Kids' Memory, Study Says

Even low levels of lead exposure can harm kids' working memory, potentially affecting their education and development, according to a new study.

Exposure to lead in the womb or during early childhood appears to increase kids' risk of memory decay, accelerating the rate at which they forget information, researchers reported July 9 in the journal Science Advances.

“There may be no more important a trait than the ability to form memories. Memories define who we are and how we learn,” said senior researcher Dr. Robert Wright, chair of environmental medicine at the Icahn School of Medicine at Mount Sinai in New York City.

“This paper breaks new ground by showing how environmental chemicals can interfere with the rate of memory formation,” Wright said in a news release.

For the study, researchers took blood lead measurements from the mothers of 576 children in Mexico during the second and third trimester of pregnancy. Later, the team took samples directly from the kids themselves, at ages 4 to 6.

Between 6 and 8 years of age, the kids took a test called the delayed matching-to-sample task, or DMST, to measure their rate of forgetting.

In the test, kids had to remember a simple shape for up to 32 seconds after it had been briefly shown to them, and then choose it from three offered options.

The test lasted for 15 minutes, with correct responses rewarding the child with tokens that could be exchanged for a toy at the end of the experiment.

“Children with higher levels of blood lead forgot the test stimulus faster than those with low blood lead levels,” Wright said.

Researchers noted that the Mexican children in the study had higher median blood lead levels than those typically found in U.S. kids 6 to 10 years old – 1.7 Ug/dL versus 0.5 Ug/dL. (Median means half were higher, half were lower.)

Children in Mexico are exposed to lead through commonly used lead-glazed ceramics used to cook, store and serve food, researchers said.

However, the Mexican kids’ blood lead levels were still lower than the 3.5 Ug/dL level used by the U.S. Centers for Disease Control and Prevention to identify kids in the United States with more lead exposure than others, researchers added.

“In the U.S., the reduction of environmental exposures to lead, such as lead-based paint in homes, lead pipes, and lead in foods such as spices, is still of continued importance as even low levels of lead can have detrimental effects on children’s cognitive function and development,” researchers wrote in their paper.

This study also shows that the DMST test can be used to help test the effect of other environmental hazards on kids’ memory, researchers said.

“Children are exposed to many environmental chemicals, and this model provides a validated method to further assess the effect of additional environmental exposures, such as heavy metals, air pollution, or endocrine disruptors, on children’s working memory,” co-lead researcher Katherine Svensson, a postdoctoral fellow in environmental medicine at the Icahn School of Medicine at Mount Sinai, said in a news release.

More information

The U.S. Centers for Disease Control and Prevention has more on childhood lead poisoning prevention.

SOURCES: Mount Sinai, news release, July 9, 2025; Science Advances, July 9, 2025