Abstract

This study was conducted to relate blood lead levels in infants to changes in lead emissions in Santiago, Chile, a heavily polluted setting where leaded gasoline began to be replaced with unleaded gasoline in 1993. Over an 18-mo period, 422 infants had blood lead levels, cotinine, and iron status determined at 12 mo. Blood lead levels fell at an average rate of 0.5 ?/dl every 2 mo, from 8.3 to 5.9 ?/dl, as the city experienced a net fall of 30% in the quantity of leaded gasoline sold. Time progression, car ownership, serum cotinine, and type of housing were significantly associated with a blood lead level ? 10 ?/dl. In this study, the authors demonstrated that infant blood lead levels, even if relatively low, can drop very rapidly in conjunction with decreases in environmental lead exposure.