Household dust metal levels in the Sydney metropolitan area

Household dust was collected from 82 residential homes within the Sydney metropolitan area. The geometric mean concentrations of metals in the household dust were Cd, 1.9 microg/g; Cr, 64.3 microg/g; Cu, 103 microg/g; Fe, 2740 microg/g; Mn, 54 microg/g; Ni, 15.6 microg/g; Pb, 85.2 microg/g; and Zn, 437 microg/g. Differences in household income level, dwelling type, or the number of occupants were not statistically significant for the majority of metals. The exceptions were higher amounts of Zn (P=0.033) and Fe (P=0.047) found in households with only 1-2 residents compared to those with 3-4 or >4 residents, and slightly higher Mn levels (P=0.033) were found in low-income households (AUD 0-30,000 dollars/year). Region was highly significant for Pb levels in Sydney but not significant for other metals. Large variations in Pb levels were found in household dust (16-16,600 microg/g), with the inner-west region associated with significantly higher Pb levels (P<0.001). Comparisons with a study from a decade earlier have revealed that the household dust Pb levels have remained constant despite substantial improvements in air quality in the inner-west area of Sydney. New epidemiological studies are required to determine whether Pb blood levels have also remained unchanged and whether accumulated Pb in household dust represents a significant health risk to children in this region.