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Predicting Residential Exposure to Phthalate Plasticizer Emitted from Vinyl Flooring: Sensitivity, Uncertainty, and Implications for Biomonitoring
Citation:
Xu, Y., E. A. COHEN-HUBAL, AND J. C. Little. Predicting Residential Exposure to Phthalate Plasticizer Emitted from Vinyl Flooring: Sensitivity, Uncertainty, and Implications for Biomonitoring. ENVIRONMENTAL HEALTH PERSPECTIVES. National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC, 118(2):253-8, (2010).
Impact/Purpose:
A three-compartment model is developed to estimate the emission rate of di-2-ethylhexyl phthalate (DEHP) from vinyl flooring (VF) and the evolving exposures in a realistic indoor environment. Exposure to DEHP via inhalation, dermal absorption and oral ingestion of dust, following the installation of VF in a typical house, is predicted.
Description:
Given the ubiquitous nature of phthalates in the environment and the potential for adverse human health impacts, there is a need to understand the potential human exposure. A three-compartment model is developed to estimate the emission rate of di-2-ethylhexyl phthalate (DEHP) from vinyl flooring (VF) and the evolving exposures in a realistic indoor environment. Exposure to DEHP via inhalation, dermal absorption and oral ingestion of dust, following the installation of VF in a typical house, is predicted. A sensitivity analysis indicates that the VF source characteristics, as well as mass-transfer coefficients and ventilation rate are important variables influencing the steady-state DEHP concentration and resulting exposure. DEHP adsorbs strongly to interior surfaces, and the interior surface area and surface/air partition coefficients strongly influence the time to steady-state. A simple uncertainty analysis suggests that residential exposure to DEHP originating from VF may fall somewhere between about 5 µg/kg/d and 180 µg/kg/d. This roughly 40-fold range in potential exposure reveals the inherent difficulty in using biomonitoring results to identify individual sources of human health risk. Nevertheless, the relatively simple dependence on source and chemical specific model parameters suggests that the exposure model could be extended to include other sources of DEHP, other sources of other semi-volatile organic compounds (SVOCs, such as biocides and flame retardants), as well as other indoor sinks. Provided appropriate parameter identification and model validation was undertaken, the resulting integrated model could provide a relatively inexpensive way to identify and control health risks associated with many of the SVOCs used in indoor materials and consumer products.
