Children's blood lead levels after the phasing out of leaded gasoline in Shantou, China

Shantou, a city in the People's Republic of China, has a central urban population of approximately 700,000 and a large number of registered vehicles (motorcycles = 256,600; other motor vehicles = 261,000). Shantou is designated as 1 of the 5 Special Economic Zones in China. The use of leaded gasoline was prohibited in the city at the end of 1998. Blood samples for lead analysis were collected from children aged 1-5 yr during the summers of 1999-2001, and the samples were analyzed using graphite furnace atomic absorption spectrometry. In 1999, 44.3% (147/332) of the children had mean blood lead levels in excess of 100 mug/l. The percentage of children with blood lead levels that exceeded 100 mug/l was reduced to 35.8% (227/635) and 23.0% (105/457) in 2000 and 2001, respectively. Average blood lead levels declined from 104 mug/l, to 94 mug/l, and 79 mug/l during the 3-yr period, respectively; the respective concordant geometric means were 97 mug/l, 85 mug/l, and 71 mug/l. Mean blood lead levels for the children studied decreased significantly (p < 0.05) every year. Among all children tested durin the 3-yr period, there were no significant differences by gender and no significant differences between children who were between the ages of 2 and 3 yr; however, those who were, 4 yr of age had blood lead levels that were significantly (p < 0.05) higher than levels in those 2 and 3 yr of age.