OBJECTIVELead intake from possible exposure routes among children residing in the Tokyo Metropolitan Area was estimated.

METHODSLead concentrations in house dust samples collected from the houses of the children and those in 24-h duplicate diet samples of the children were determined. The daily lead intake was estimated by multiplying the lead concentrations in the house dust, diet, soil and ambient air (the latter two were from the literatures) by the corresponding intake and/or inhalation rates, and summing all of the products. Bioaccessibility tests were performed on the house dust, soil and diet samples to determine the lead uptake level.

RESULTSChildren residing in the Tokyo Metropolitan Area were estimated to be exposed to 21.5 μg of lead on a daily basis, with a maximum intake of up to 70.4 μg. The average weekly intake per kg body weight for a 5-year-old Japanese child was found to be 8.0 μg/kg bw/wk, which is below the Provisional Tolerable Weekly Intake (PTWI) of 25 μg/kg bw/wk. However, the maximum weekly intake was found to be 26 μg/kg bw/wk.

CONCLUSIONSHouse dust and soil ingestion can be the predominant routes of exposure to lead among children in Japan, and the source(s) of lead in such media must be specified to reduce the lead intake level of the children.