OBJECTIVETo investigate the blood lead levels (BLLs) in children after 10-year use of unleaded gasoline in Guangzhou and evaluate the effect of this measure.

METHODSThrough stratified random sampling method, 4 kindergartens and 4 elementary schools were selected from each of three districts among 12 districts of Guangzhou. Totally 2373 children were recruited into this survey and 1-2 ml blood was sampled from each child through vein. The lead concentration in blood samples was determined with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) after diluted with 0.1% Triton X-100 and 0.1% HNO(3) in the ratio of 1:20.

RESULTSAmong 2373 children, the highest BLL was 330 microg/L, while the lowest was 10 microg/L. Geometric mean (GM) of BLL was 58.28 microg/L with 61.11 microg/L of male and 55.37 microg/L of female (t=8.671, P=0.000). Sixty (2.51%) children were identified as elevated BLLs (>or=100 microg/L), including 36 (2.90%) male and 24 (2.09%) female (chi2=1.594, P=0.207). Compared to the surveys conducted in China 10-year ago, the children with elevated BLLs decreased 96.28% and the GM of BLLs reduced 58.37%. BLLs in suburb children (60.33 microg/L) were higher than those in downtown (58.09 microg/L) or in countryside (56.72 microg/L).

CONCLUSIONThe BLLs in children and the ratio for children with elevated BLLs, had declined dramatically after 10-year implement of unleaded gasoline in Guangzhou.