Factors Related to Elemental Variation in House Dust

Concentrations of 25 elements (Al, Ba, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sn, Sr, Ti, U, V, Zn) in house dust samples of households in Tokyo Metropolitan Area and Chugoku district in Japan were measured and the source(s) of their household-to-household variations were analyzed with particular focus on those of Pb variation. Vacuum cleaner dusts were supplied from 2-6 households from each of 8 apartment buildings and one pair of adjacent houses constructed by the same house-maker (total number of samples: 27). House dust samples, prepared by passing the cleaner dust through 250 μm mesh, were acid-digested and element concentrations were determined by ICP emission spectrometry and ICP mass spectrometry. Inter-household variation in elemental concentration, as well as that of elemental ratio to Al calculated to correct for the effect of outdoor soil/dust, was large. Elemental ratio to Al did not differ among the buildings for all of the elements except for Mg, indicating element level in house dust varies more due to “dweller′s factor” than to locality and/or materials for the construction of the buildings. The result of correlation analysis indicated paint and general heavy metal pollution involving Cd, Cu, Ni or Zn of unknown source as source of Pb in house dust, which was consistent with the result of the previous study. Additionally, Pb-Sn correlation indicated solder as another source while no candidate source emerged with regard to highly significant Pb-Mo correlation.