Estimating the proportion of bioaccessible lead (BaPb) in household dust wipe samples: a comparison of IVBA and PBET methods

Abstract

Established methods for using standardized dust wipes to collect and measure total lead in household dust are readily available but the use of dust wipes to measure bioaccessible lead (BaPb) is less clear. This study compared two in vitro methods for estimating the proportion of BaPb in dust collected into dust wipes including the US-EPA’s in-vitro bioaccessible assay (IVBA) method at two pH (1.5 and 2.5) values; and the physiologically based extraction test (PBET 2.5 pH). Two types of simulated household dust samples (Pb-soil contaminated and Pb-paint contaminated) each with three Pb concentrations were created. Equal amounts of simulated dust were applied to a smooth surface and collected following the standard EPA dust wipe protocol and were analyzed for BaPb and total Pb (ASTM-E1644-17, ICP-OES). Estimated BaPb levels differed significantly by the method of extraction. Mean percent BaPb were IVBA pH 1.5, > 90% (Pb-paint) and 59–63% (Pb-soil); IVBA pH 2.5 78–86% (Pb-paint) and 45–50% (Pb-soil); PBET pH 2.5 56 to 61% (Pb-paint) and 41–50% Pb-soil). Particularly for lead-paint contaminated dust, PBET showed significantly greater discrimination as suggested by the broader range of BaPb values and closer approximation to total lead concentrations in simulated household dust samples.

Keywords:

• Bioaccessible lead
• dust wipes
• PBET
• IVBA
• paint dust
• pH
• soil dust

Data availability statement

The data that support the findings of this study are available in Mendelay Data at DOI: 10.17632/z6y7wfc745.1.

Additional information

Funding

This work was supported by the U.S. Department of Housing and Urban Development (Grant No. TXLTS-10018-01), USA. The authors thank soil and environmental chemistry lab group members at the Kansas State University and Lead research team at University of El Paso for their assistance during the study period. Contribution No. 23-198-J from the Kansas Agricultural Experiment Station. This work is also supported by National Institute of General Medical Sciences and the USDA National Institute of Food and Agriculture, NC 1187 multi-state project.