Chemical mass balance source apportionment of lead in house dust

Chemical mass balance was used to apportion the major proximate contributors of lead mass to house dust (HD(Pb)) obtained from urban Jersey City, NJ, homes of children at risk for lead exposure. Coarse (up to ~60 μm) and PM₁₀ (<10 μm) particle size fractions of vacuum dust samples from 64 residences with lead-based paints were analyzed for Pb and 16 other elements. Source profiles were developed to represent proximate source media contributors to HD(Pb) pre-1960 interior lead-based paints, indoor air, and a crustal source profile that accounted for the contribution of yard soils and street dusts. On average for both size fractions the exterior proximate sources, i.e., crustal materials and deposited airborne particulates, were responsible for approximately two-thirds of the HD(Pb) mass; the interior lead-based paint sources contributed the remaining third. Results indicate considerable variability in Pb source contributors between homes, but little difference in the source contributors to the two overlapping size fractions within homes. Effective reduction of HD(Pb) levels will require control of both exterior and interior sources.