Higher exposure to lead in childhood is associated with a greater likelihood of criminality, a review of 17 studies has found, but whether the element is causing the behaviour rather than just being associated with it is unknown
By Michael Le Page
1 August 2023
A blood sample being taken from a 3-year-old girl in Flint, Michigan, to test for exposure to lead
JIM WEST/SCIENCE PHOTO LIBRARY
The more lead that people are exposed to in childhood or in the uterus, the more likely they are to engage in criminal behaviour as teenagers or adults, according to a review of 17 studies.
“The evidence shows an excess risk for criminal behaviour years later,” says Maria Jose Talayero at the George Washington University in Washington DC.
Lead exposure has fallen in many countries, mainly due to the removal of lead additives from petrol (gasoline). However, there is no safe level – any amount of exposure is thought to be harmful.
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It is estimated that 1 in 3 children globally have blood lead levels above 5 micrograms per decilitre, which can result in decreased intelligence, behavioural difficulties and learning problems. The effects are irreversible.
In Mexico, for instance, the main source of exposure is the continued addition of lead to the glazes on pottery, says Talayero. Other sources of exposure include lead piping, electronic waste and eating birds shot with lead pellets.