Exposure to leaded gasoline lowered the IQ of about half of the United States population; estimates a new study. The study, published Monday in the journal Proceedings of the National Academy of Sciences, focused on people born before 1996 – the year the US banned leaded gas.
Overall, researchers from Florida State University and Duke University found that childhood lead exposure cost America about 824 million units, or 2,6 units per person on average.
Some groups were even more affected than others.
For people born in the 1960s and 1970s, when leaded gas consumption was skyrocketing, the IQ loss was estimated to be as much as 6 points, and for some more than 7 points.
The team behind the study used natural gas consumption data, population estimates and many other data to estimate that by 2015, more than 170 million Americans had blood lead levels above 5 micrograms per deciliter in their early childhood.
The damage from this came mainly from inhaling the auto exhaust.
Lead is a neurotoxin and no amount of it is safe. Currently, 3,5 micrograms per deciliter is a reference value for blood lead levels that should be considered high. The acceptable limit was once higher.
