The co-author of a new landmark study that says lead exposure caused 151 million Americans to become depressed, anxious, inattentive or hyperactive has called for it to be banned.
Lead was first added to gasoline in 1923 to keep car engines running smoothly, as unleaded gasoline combusted unevenly and produced engine-knocking sounds. It was added to gasoline until a ban in 1996 but the technological improvement came at the expense of the U.S. public's well-being a new study suggests.
"I think we need to move away from using lead as a society," Aaron Reuben, Assistant Professor of Clinical Neuropsychology at the University of Virginia told Newsweek. "The more we learn about lead the more we understand that the costs of using it—to children, families, and society—are always greater than the benefits."
Reuben is co-author of a new study published in the Journal of Child Psychology and Psychiatry along with Michael McFarland and Mathew Hauer, both professors of sociology at Florida State University, which has investigated the impact of lead on the mental health of Americans over many decades.
"Lead is still used in bronze, bullets, many types of paint, airplane fuel, car batteries—the list goes on and on. Better alternatives exist and should be used. Whenever a company produces a product that uses lead, they gain the benefits—profit—and everyone else bears the cost. It's time to end that."
What chemicals are American children exposed to?
Bruce Lanphear—a population health scientist at Simon Fraser University in Vancouver who did not take part in the study—studies early childhood health, lead poisoning, environmental neurotoxins and the epidemiology of asthma.
"This paper is important because it helps people appreciate how widespread exposure to a toxic metal, lead, can result in substantial mental health problems," Lanphear told Newsweek.
"American children are exposed to many other chemicals suspected of being toxic, like phthalates, PBDEs—chemical flame retardants—and air pollution. This study is a wake-up call about how widespread exposures to toxic chemicals contribute to the epidemic of mental health problems in children and adults."
Over the past century, lead was used in paint, pipes, solder, and automotive fuel with numerous studies linking lead exposure to neurodevelopmental and mental health problems, particularly conduct disorder, attention-deficit, hyperactivity disorder and depression.
Lead is neurotoxic and can erode brain cells and alter brain function after it enters the body. As such, there is no safe level of exposure at any point in life, health experts say. Young children are especially vulnerable to lead's ability to impair brain development and alter brain health.
How did scientists investigate US lead exposure?
Using historical data on U.S. childhood blood-lead levels, leaded-gas use, and population statistics, the researchers determined the likely lifelong burden of lead exposure carried by every American alive in 2015.
"We saw very significant shifts in mental health across generations of Americans," Hauer said. "Meaning many more people experienced psychiatric problems than would have if we had never added lead to gasoline."
Lead exposure led to greater rates of diagnosable mental disorders, like depression and anxiety, but also greater rates of individuals experiencing more mild distress that would impair their quality of life.
"For most people, the impact of lead would have been like a low-grade fever," Reuben said. "You wouldn't go to the hospital or seek treatment, but you would struggle just a bit more than if you didn't have the fever."
Lead's effect on brain health has also been linked to changes in personality that show up at the national level.
"We estimate a shift in neuroticism and conscientiousness at the population level," McFarland said.
As of 2015, more than 170 million Americans had clinically concerning levels of lead in their blood when they were children, likely resulting in lower IQs and more mental health problems and likely putting them at higher risk for other long-term health impairments, such as increased cardiovascular disease.
Leaded gasoline consumption rose rapidly in the early 1960s and peaked in the 1970s. As a result, Reuben and his colleagues found that essentially everyone born during those two decades were nearly certain to have been exposed to pernicious levels of lead from car exhaust.
Reference
"Contribution of Childhood Lead Exposure to Psychopathology in the U.S. Population over the Past 75 Years," Michael J. McFarland, Aaron Reuben, Matt E. Hauer. Journal of Child Psychology and Psychiatry, December 4, 2024. DOI: 10.1111/jcpp.14072
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