A study of a century’s worth of US hair samples showed that lead exposure has fallen more than 100-fold since the 1960s.
High concentrations of lead cause developmental damage in children, notably neurological effects as well as cardiovascular, reproductive, and kidney problems. Lead’s use in petrol, paint, and elsewhere meant it was omnipresent in the mid-20th century until bans — such as the 1970 US Clean Air Act — began to take effect.
The new study found that in Utah, lead exposure peaked between 1960 and 1964 at 120 times modern rates; previous research has found enormous falls in Europe. But Africa still has a major problem, driven by at-home recycling of car batteries.