A new study has said that leaded gasoline is to be blamed for nearly two-thirds of toxic lead ingested or inhaled by African-American children in Cleveland during the latter two-thirds of the 20th century.
According to researchers from Case Western Reserve University, their findings probably apply to many cities across the US and reinforce concerns about the health threat for children in countries still using leaded gasoline.
However, they emphasize that the results do not minimize the ongoing importance of current childhood lead exposure due to persistence and deterioration of leaded paint which was used as late as the 1960's.
Extrapolation from lead analyses of teeth from 124 residents of urban Cleveland neighbourhoods show that "at the peak of leaded gasoline usage, in the 1960's and early 70's, the levels of lead in the bloodstream were likely to be toxic," said Norman Robbins, emeritus professor of neurosciences at Case Western Reserve School of Medicine.
Research of others has shown that these levels of lead are associated with significant neurological and behavioural defects lasting into adulthood, he said.
"It raises the question, has leaded gasoline had a lasting effect on many present-day Cleveland adults?" Robbins said.
Robbins, who began the study 17 years ago, put together an interdisciplinary team to determine what was the predominant recent historic source of lead exposure within the city.
Leaded gasoline, lead paint, and lead soldering in food cans had been implicated.
Jiayang Sun, professor of statistics at CWRU and a co-author of the study, said: "The findings are important today.
"Some countries are still using leaded gasoline."
The study appears in Science of the Total Environment.