Measuring Pb bioavailability from household dusts using an in vitro model

Despite an extensive cleanup program in the Port Pirie region, South Austra lia, the levels of lead (Pb) in blood of children have been found to exceed the "level of concern" (10 mu g/dL). The ingestion of household dust is a major pathway for elevated blood lead by children in the community. Signifi cant differences in levels of Pb in blood in children were observed in vari ous localities around the smelter. In this study an in vitro test was asses sed as one method for determining the bioavailability of Pb in household du st and for predicting levels of Pb in blood of children. The solubility of Pb in the dust decreased significantly as pH of the in vitro mixture increa sed. Correlation studies with average blood Pb levels of children in the co rresponding area and in vitro measures of Pb bioavailability found that the best relationship was with total dust Pb (r(2) = 0.92, **). A significant positive relationship was also found with Pb concentrations determined in t he in vitro test at pH 3.0 (r(2) = 0.82, **). This suggested that for these dust samples, which all had a similar environmental matrix, the use of the in vitro test was not a better indicator of blood Pb levels in children co mpared with a total Pb analysis.