Leaded petrol may have decreased IQ by an average of 5.9 points among people born in the US in the mid-to-late 1960s.
to make car engines run more smoothly. If the substance enters the brain, it can disrupt nerve signalling and, at higher levels, kill brain cells. Young children are particularly susceptible due to the metal disrupting brain development.Using data from a national survey, Reuben and his colleagues analysed the circulating lead levels of over 11,600 children aged 1 to 5 years from blood samples drawn between 1976 and 2016.
Their results suggest half the current US population had elevated lead levels in their blood as children. Across the country, they estimate that lead exposure may have caused an average IQ drop of 2.6 points. People born in the mid-to-late 1960s may have lost an average of 5.9 points. In the 1970s, it was recognised that tiny particles of lead in exhaust fumes could enter people’s bloodstreams and higher environmental levels of the metal were linked with worse school performance in children.