After growing up poor in a predominantly African-American neighborhood of Cincinnati, the young adults had reached their early 20s. One by one, they passed through an MRI machine that displayed their brains in sharp, cross-sectioned images.
For those who had been exposed to lead as toddlers, even in small amounts, the scans revealed changes that were subtle, permanent and devastating.
The toxic metal had robbed them of gray matter in the parts of the brain that enable people to pay attention, regulate emotions and control impulses. Lead also had scrambled the production of white matter that transmits signals between different parts of the brain, largely by mimicking calcium, an element that plays a critical role in brain development.
Scars left by lead have had significant consequences for the study participants and their communities. As children, they struggled in school more than those who had not been exposed. As teens, they committed crimes more frequently, University of Cincinnati researchers reported.
"What we found — and continue to find — is that lead sowed the seeds of their future," said Kim Dietrich, a neuropsychologist who has been following the group of nearly 300 people since they were born in the late 1970s. "It isn't conducive to behavior we associate with normal development, making smart decisions and success."
