CHICAGO – 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.”
People have known for centuries that lead is poisonous, and removing it from gasoline and paint has dramatically reduced exposure for American children.
But a growing body of research is making it clear that the toxic legacy of lead has far more wide-ranging effects than previously known.
Lingering dust from paint and deposits from old vehicle emissions continue to harm thousands of children in older industrial cities like Cincinnati and Chicago.
Once an obscure academic specialty, lead poisoning is gaining new appreciation from economists, criminologists and education experts as researchers document how early exposure harms children in ways that don’t become apparent until years later.
The damage ends up costing taxpayers in the form of increased spending on health care, special education and law enforcement.
Last month, a Chicago Tribune investigation found that lead hazards are festering in the same parts of Chicago that have given the city a national reputation for violence and academic failure. In impoverished, crime-ridden neighborhoods like Austin, Englewood and Lawndale, more than 80 percent of the children tested in 1995 had dangerous lead levels.
Today those kids are in their early to mid-20s, when criminal behavior peaks.
As evidence mounts of the links between lead poisoning, poor school performance and crime, some scientists are starting to focus on lead pollution as a key factor in Chicago’s violence.
“People in neighborhoods like Englewood have faced multiple assaults over different periods of time – job losses, segregation, housing discrimination,” said Robert J. Sampson, a Harvard University researcher who has been studying Chicago for more than two decades. “Yet through all of that there is this persistent lead poisoning. It creates a social context where kids are at a clear disadvantage.”
Sampson recently added lead data to his existing research on poverty, education and crime in Englewood and other neighborhoods. The results, he said, were shocking. A map of lead poisoning rates among children younger than 6 in 1995, for instance, looks very similar to a map of aggravated assault rates in 2012, when those kids were 17 to 22 years old.
“It’s not something I appreciated before,” Sampson said. “But when I see the astounding levels of lead poisoning in these communities, it makes complete sense that it is part of the cycle of deprivation.”
Politicians and policymakers have yet to catch up to this line of thinking, seemingly regarding lead pollution as a problem solved long ago. During the past five years, federal and state officials have sharply cut funding to screen kids, inspect properties and eliminate lead hazards.
With less money directed at the problem, children ages 5 and younger continue to be harmed at rates up to six times the Chicago average in corners of predominantly African-American neighborhoods on the South and West sides, according to the Tribune’s analysis of city records.
One researcher working in Chicago, Anne Evens, recently published a study that draws a sharper focus on how lead is still ravaging the city years after it faded as a local and national issue.
A former chief of lead poisoning prevention at the Chicago Department of Public Health, Evens obtained the lead tests of more than 58,000 children born in the city from 1994 to 1998 and compared the results with how they performed on standardized tests in third grade.
Her peer-reviewed study, published in April in the scientific journal Environmental Health, found that exposure to lead during early childhood significantly increased the chance that a student would fail reading and math tests, even when controlling for other factors such as poverty, race, birth weight and the mother’s education level.
The scope of what Evens found is staggering: At three-quarters of Chicago Public Schools, the average lead level of third-graders exceeded a standard established by the Centers for Disease Control and Prevention in each year from 2003 to 2006.
Given the scale of lead hazards in Chicago, advocates say political leaders are overlooking a cost-effective way to help improve schools and reduce crime.
“Of all the problems that affect kids in these neighborhoods, lead is the easiest to solve,” said Evens, who now heads Elevate Energy, a nonprofit that addresses lead issues while making homes more energy-efficient. “But there just isn’t the political will to do something about it.”