Lead disrupts calcium metabolism, hemoglobin synthesis, and neural function. The symptoms include anemia, abdominal colic, and, most important, impaired neurological function, which in infants and children can cause long-term, probably permanent, damage, including mental retardation at high exposure levels, and cognitive deficits detectable by neuropsychological tests among children with relatively low background lead exposure levels. This effect has been confirmed in cohort studies in several parts of the world. The toxic effects of lead were known to the Roman scholar Pliny the Elder (23–79 ce) and described by the British physician George Baker (1722–1809), but it took persuasive scientific evidence of neurological damage to children and persistent public outrage to induce legislators to enact moderate safeguards by the late 20th century, and even these were resisted by the lead industry.
Subjects: Public Health and Epidemiology.