Indoor Residential Fate Model of Phthalate Plasticizers

Abstract

Phthalates are ubiquitous pollutants in indoor environments and have emerged as a serious public concern due to their adverse effects on humans. Using emissions of di-2-ethylhexyl phthalate (DEHP) from vinyl flooring as an illustrative example, we developed a three-compartment model to predict the fate and transport of phthalates in a residential home. The model considered eight environmental media (i.e. air, particulate matter with six size fractions, vinyl flooring, carpet, furniture, settled dust, wall and ceiling). Particle movement (deposition and resuspension), dust removal (vacuuming), indoor cooking, and adsorption/absorption on indoor surfaces are also included. The predicted airborne DEHP concentrations at steady state are within the range of 0.1 ?g/m3 to 0.2 ?g/m3. After vinyl flooring (the primary source) is removed, it takes 2 years for indoor airborne DEHP level to reduce to below 0.01 ?g/m3, and the time doubles when carpet presents. Field measurements in a test house are conducted to validate the model, and the model predictions are of the same order of magnitude as measured data. Finally, the exposures to DEHP as well as several other phthalates via inhalation, dermal absorption from gas and deposited particles, and non-dietary ingestion of dust are evaluated. The daily exposure levels shows that several effective removal strategies might be necessary to lower the exposure level.