Predicting Residential Exposure to Phthalate Plasticizer Emitted from Vinyl Flooring: A Mechanistic Analysis

Abstract

A two-room model is developed to estimate the emission rate of di-2-ethylhexyl phthalate (DEHP) from vinyl flooring and the evolving gas-phase and adsorbed surface concentrations in a realistic indoor environment. Because the DEHP emission rate measured in a test chamber may be quite different from the emission rate from the same material in the indoor environment the model provides a convenient means to predict emissions and transport in a more realistic setting. Adsorption isotherms for phthalates and plasticizers on interior surfaces, such as carpet, wood, dust, and human skin, are derived from previous field and laboratory studies. Log-linear relationships between equilibrium parameters and chemical vapor pressure are obtained. The predicted indoor air DEHP concentration at steady state is 0.15 microg/m3. Room 1 reaches steady state within about one year, while the adjacent room reaches steady state about three months later. Ventilation rate has a strong influence on DEHP emission rate while total suspended particle concentration has a substantial impact on gas-phase concentration. Exposure to DEHP via inhalation, dermal absorption, and oral ingestion of dust is evaluated. The model clarifies the mechanisms that govern the release of DEHP from vinyl flooring and the subsequent interactions with interior surfaces, airborne particles, dust, and human skin. Although further model development, parameter identification, and model validation are needed, our preliminary model provides a mechanistic framework that elucidates exposure pathways for phthalate plasticizers, and can most likely be adapted to predict emissions and transport of other semivolatile organic compounds, such as brominated flame retardants and biocides, in a residential environment.

Indoor SVOC pollution in China: A review

“…The plasticizers and flame retardants in the materials may emit from the sources. The study results of Xu et al [31] showed that the internal diffusion resistance for SVOCs can be ignored compared with the external mass transfer resistance. Therefore, the emission process is the external mass transfer (partitioning into the gas phase, the convective mass-transfer) controlled process.…”

“…The previous study showed that the relationship of linear transient reversible balance can also satisfy the adsorption between the gas-phase and the surface of wall and furniture accurately [31].…”

First tier modeling of consumer dermal exposure to substances in consumer articles under REACH: A quantitative evaluation of the ECETOC TRA for consumers tool

“…This model is grounded on the well established theory of diffusion of substances in materials. Diffusion models have been successfully applied and tested in a number of areas, including the estimation of emission of substances from building materials (Huang and Haghighat, 2002) flooring (Xu et al, 2009), and migration of substances from packaging materials into food stuff (Brandsch, 2002;Begley et al, 2005). For a range of substances and materials these models provide experimentally verified methods and input data (i.e.…”

“…Models that describe the diffusion of substances in materials have been developed and successfully applied in the fields of exposure assessment of chemicals from building materials and flooring (Huang and Haghighat, 2002;Xu et al, 2009) and the modeling of migration of chemicals from food packaging (Brandsch, 2002;Begley et al, 2005).…”

Modeling and analysis of sampling artifacts in measurements of gas-particle partitioning of semivolatile organic contaminants using filter-sorbent samplers

“…Inhalation, dermal absorption, and nondietary ingestion of settled dust have been identified as the major exposure pathways to SVOCs (Allen et al, 2007;Frederiksen et al, 2009;Harrad et al, 2006;Meeker et al, 2009;Nazaroff, 2010, 2014;Wilson et al, 2009;Xu et al, 2009 andXu et al, 2010). A number of field campaigns have been conducted to measure air concentrations of SVOCs in indoor (Blanchard et al, 2014;Kolarik et al, 2008;Trabue et al, 2008;Wang et al, 2014 andXu et al, 2014) and outdoor environments (Albinet et al, 2007;Chao et al, 2003;He and Balasubramanian, 2010;MacLeod et al, 2007 andXie et al, 2014b).…”