Abstract
Since children spend most of their time indoors and they have hand-to-mouth behavior, house dust ingestion can be a potential exposure pathway for some non-volatile chemicals. In order to identify which chemicals in house dust need to be further investigated in Japan, we collected literature data on the concentration of selected chemicals (metals, polybrominated diphenyl ethers, polycyclic aromatic hydrocarbons (PAHs), phthalates, dioxins, DDT, chlorpyrifos, perfluorooctanesulfonic acid, bisphenol A and nonylphenols) in house dust and estimated the exposure level via the house dust ingestion. We calculated hazard quotients (HQs) and excess cancer risks for the chemicals. The HQ at 95 percentile of estimated exposure level for lead and 2,4-diethylhexyl phthalate (DEHP) was 0.2 and 1.7, respectively. These exceeded acceptable HQ of 0.1 that was tentatively set in this study. The excess cancer risk at 95 percentile of estimated exposure level for inorganic arsenic, PAHs and dioxins was 3×10-5, 1×10-3 and 8×10-5, respectively. These exceeded acceptable excess cancer risk of 10-5. In addition, intake of lead, DEHP and PAHs via the house dust ingestion was significant when compared with that from other pathways such as food, air and soil. On the other hand, contribution of house dust ingestion to total inorganic arsenic and dioxins exposure level was negligible, so any countermeasure to house dust was not considered effective to lessen health risk due to inorganic arsenic and dioxins exposure. We concluded that lead, DEHP and PAHs are the chemicals of priority to be further investigated for Japanese house dust to fully characterize its health risk to children.
