The use of isotope ratios to apportion sources of lead in Jersey City, NJ,house dust wipe samples

Lead stable isotope ratio (IR) analysis by inductively coupled plasma mass spectrometry was used to examine the relationship between sources of Pb in 22 dust wipe samples collected from 10 homes in Jersey City, NJ. Common lea d sources examined included interior lead-based paints, exterior soils and street dusts, and indoor air. High correlations between IRs of wipe samples and both street dusts and exterior soils indicated these two exterior sour ces were indistinguishable. They were treated as a single exterior source i n a source apportionment using IR matching and a simple mixing model. The u pper-bound estimate of the contribution of interior lead-based paints to 10 floor-and eight sill-wipe samples was 56% and 50%, respectively. It was no t possible to apportion sources in four of the 22 samples because wipe samp le IRs were outside the range of measured sources. Examination of means obs cures the variability in the data, however, as eight of the 18 apportioned samples matched interior or exterior source media. In most cases, however, sources from outside the home contribute as much Pb to house dust wipe samp les as interior lead-based paints. (C) 1998 Elsevier Science B.V. All right s reserved.