Measuring Pb bioavailability from household dusts using an in vitro model

Despite an extensive cleanup program in the Port Pirie region, South Australia, 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. Significant differences in levels of Pb in blood in children were observed in various localities around the smelter. In this study an in vitro test was assessed as one method for determining the bioavailability of Pb in household dust 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 increased. Correlation studies with average blood Pb levels of children in the corresponding 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 the 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 compared with a total Pb analysis.