CHEMICAL MASS-BALANCE SOURCE APPORTIONMENT OF LEAD IN-HOUSE DUST

Chemical mass balance was used to apportion the major proximate contri butors of lead mass to house dust (HDPb) obtained from urban jersey Ci ty, NJ, homes of children at risk for lead exposure. Coarse (up to sim ilar to 60 mu m) and PM10 ( <10 mu m) particle size fractions of vacuu m dust samples from 64 residences with lead-based paints were analyzed for Ph and 16 other elements. Source profiles were developed to repre sent proximate source media contributors to HDPb pre-1960 interior lea d-based paints, indoor air, and a crustal source profile that accounte d for the contribution of yard soils and street dusts. On average for both size fractions the exterior proximate sources, i.e., crustal mate rials and deposited airborne particulates, were responsible for approx imately two-thirds of the HDPb mass; the interior lead-based paint sou rces contributed the remaining third. Results indicate considerable va riability in Pb source contributors between homes, but little differen ce in the source contributors to the two overlapping size fractions wi thin homes. Effective reduction of HDPb levels will require control of both exterior and interior sources.