生活用品の鉛含有量と可給態鉛量

抄録

Lead is a neurotoxin and it has a significant adverse effect on the neurobehavioral development of children due to a low-level exposure. In order to see if lead-containing household products are present in the indoor environment in Japan, various products (n=250) were analyzed for total lead concentration with an X-ray fluorescence spectrometry. Lead was detected in 18 of 250 samples at the concentration 0.019 to 14%. It was found that lead was contained in paints and polyvinyl chloride (PVC) covering of the products. Two samples with painted surface had concentrations of lead exceeding 0.06% in the paint, the regulatory limit set by the Japan Paint Manufacturers Association. Eight samples with PVC covering (e.g. extension cord, supply cable) had more lead concentrations than the tolerable maximum concentration value of the RoHS directive in 2006 (0.1%). These products were produced outside Japan, or produced before execution of the RoHS directive. Bioaccessibility of lead in the products was relatively low, ranging from 0.43 to 4.6%. Daily bioaccessible lead intake of a child via the ingestion of fragments of such products was estimated to range from 0.21 to 90 µg/day, and total daily bioaccessible lead intake including contributions from other media (e.g. diet and soil) was estimated to be 4.7 to 94 µg/day. Blood lead concentration of a child, who ingests this amount of bioaccessible lead, was estimated to be 0.75 to 15 µg/dL based on a model formula of the EPA. The result suggested that products with extremely high lead concentration can pose health risk to children via the ingestion of house dust contaminated with fragments of surface covering of such products.