In a paper published in the Proceedings of the National Academy of Sciences on Monday, they estimated that half the U.S. adult population in 2015 had been exposed to lead levels surpassing five micrograms per deciliter — the Centers for Disease Control and Prevention threshold for harmful lead exposure at the time. That's more than 170 million people who have been exposed to the dangers of lead!
Scientists from the University of Florida and Duke University found that 90% of children had blood lead levels higher than what is acceptable between 1950 and 1981.
This new study demonstrates that lead poisoning is an ongoing problem and is not only related to lead paint issues. Lead exposure is a serious national health issue and researchers found a significant impact on cognitive development: on average, early childhood exposure to lead resulted in a 2.6-point drop in IQ.
Study lead author Michael McFarland, an associate professor of sociology at Florida State University, said the findings were “infuriating” because it was long known that lead exposure was harmful, based on anecdotal evidence of lead’s health impacts throughout history.
Though the U.S. has implemented tougher regulations to protect Americans from lead poisoning in recent decades, the public health impacts of exposure could last for several decades, experts told the Associated Press.
“Childhood lead exposure is not just here and now. It’s going to impact your lifelong health,” said Abheet Solomon, a senior program manager at the United Nations Children’s Fund.
Early childhood lead exposure is known to have many impacts on cognitive development, but it also increases the risk for developing hypertension and heart disease, experts said.
“I think the connection to IQ is larger than we thought and it’s startlingly large,” said Ted Schwaba, a researcher at the University of Texas-Austin who studies personality psychology and was not part of the new study.