Ingesting lead, even tiny amounts, can harm neurological development, particularly for young children. “There’s research to show it’s correlated with juvenile justice outcomes and poor performance in schools,” says Penn criminologist John MacDonald.
It’s why in the United States, the Environmental Protection Agency has worked for decades to reduce environmental exposure, setting limits on lead allowed in paint and food cans, for example, and putting in place the Safe Drinking Water Act. Although public water sources must all meet the Act’s stringent health requirements, private wells—on which some 13% of the U.S. population relies—fall beyond its purview.
MacDonald and colleagues from Indiana University, Bloomington; the University of North Carolina, Chapel Hill; and Duke University wanted to know what that meant and what potential long-term consequences this might have. They found that, for teens in the U.S., early lead exposure from private well drinking water increased the risk of juvenile delinquency, research they published in the Proceedings of the National Academy of Sciences.
“For people who are drinking water that has lead in it, we can show there’s a strong causal connection to what comes later in the life,” MacDonald says. “That to me is key.”
The research collaboration came about in an unusual way for MacDonald: through his sister, Jacqueline MacDonald Gibson, an environmental engineer at Indiana University. “She was talking about her work on water contamination in well water in North Carolina,” he says. “She mentioned that lead levels were high there, higher than what had been flagged in the Flint water crisis.”
MacDonald knew that the criminology literature had already established a strong connection between lead and juvenile delinquency. He also noticed that because the divide between which houses use well water and which use municipal sources is relatively arbitrary, the data Gibson had been analyzing offered a kind of natural experiment.
They decided to look for connections between the well water, lead, and juvenile delinquency, in this case defined as official complaints or records in the juvenile court system for felony offenses or misdemeanor assaults. “Essentially we included kids sent to court for conduct that would’ve gotten them arrested as an adult,” says MacDonald. Those data came from the North Carolina Department of Public Safety.
In addition to that and the information about household water source, the research team secured a third dataset, this one from the North Carolina Childhood Lead Poisoning Prevention Program, looking at blood lead measurements. Combining all three, they built a longitudinal dataset linking blood lead measurements for 13,580 children younger than 6 to their drinking water source, individual- and neighborhood-level demographics, and reported juvenile delinquency records.
The researchers found that, compared to children with municipal water, those relying on private wells had a 21% higher risk of being reported for any delinquency and a 38% increased risk of being reported for serious delinquency after age 14.
“No amount of lead in water is good for people, especially for kids. That being said, exposure to lead at a very young age is not determinative,” MacDonald says. “In other words, just because you’re exposed to lead doesn’t mean you will definitely encounter the juvenile justice system, but it increases your risk.”
“It’s like secondhand smoke,” he adds. “Secondhand smoke isn’t good for you, but it doesn’t ensure that people exposed to it are going to end up with lung cancer. It increases their risk. That’s an important distinction for lead in well water, because it’s not a complicated problem to fix.”
What’s needed, he says, is greater awareness of the contaminants that well water may contain coupled with initiatives that simply and inexpensively remove them, such as state- or county-run programs that distribute water-filtration systems or subsidies at little to no cost. “I hope this work will help influence these decisions,” he says. “It’s worth it in terms of the longer-term cost to public health and kids.”
Funding for this work came from the U.S. Environmental Protection Agency Science to Achieve Results Program (Grant 83927901).
John MacDonald is a professor in the Department of Criminology and the Department of Sociology in the School of Arts & Sciences at the University of Pennsylvania. Other contributors to the research included Jacqueline MacDonald Gibson, Xiwei Chen, and undergraduate Aralia Pawlick of Indiana University, Bloomington; Michael Fisher of the University of North Carolina, Chapel Hill; and Philip J. Cook of Duke University.
