"About half of U.S. adults alive today were exposed to harmful levels of lead as children from the burning of leaded gasoline, according to a new study, which estimates that lead contamination has lowered Americans’ IQ scores by more than two points on average.
Lead can erode brain cells and poses a particular threat to children, impairing brain development in those with heavy exposure. Researchers used data on childhood blood-lead levels, leaded gas use, and population to gauge the lifetime exposure of every American adult in 2015.
Results show that more than 170 million Americans had exposure to concerning levels of lead as children, increasing their risk of cardiovascular disease, mental illness, and reduced cognitive ability. Drawing on existing research into the effect of lead on IQ, researchers estimate that Americans lost 2.6 IQ points on average as a result of contamination from leaded gasoline. The findings were published in the Proceedings of the National Academy of Sciences."
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