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Predicting SVOC Emissions into Air and Foods in Support of High-Throughput Exposure Assessment
Citation:
Isaacs, K., C. Nicolas, D. Biryol, AND J. Wambaugh. Predicting SVOC Emissions into Air and Foods in Support of High-Throughput Exposure Assessment. 2016 Annual ISES Meeting, Utrecht, NETHERLANDS, November 09 - 13, 2016.
Impact/Purpose:
The release of semi-volatile organic compounds (SVOCs) from consumer articles may be a critical human exposure pathway. In addition, the migration of SVOCs from food packaging materials into foods may also be a dominant source of exposure for some chemicals. Here we describe recent efforts to characterize emission-related parameters for these exposure pathways to support prediction of aggregate exposures for thousands of chemicals.
Description:
The release of semi-volatile organic compounds (SVOCs) from consumer articles may be a critical human exposure pathway. In addition, the migration of SVOCs from food packaging materials into foods may also be a dominant source of exposure for some chemicals. Here we describe recent efforts to characterize emission-related parameters for these exposure pathways to support prediction of aggregate exposures for thousands of chemicals For chemicals in consumer articles, Little et al. (2012) developed a screening-level indoor exposure prediction model which, for a given SVOC, principally depends on steady-state gas-phase concentrations (y0). We have developed a model that predicts y0 for SVOCs in consumer articles, allowing exposure predictions for 274 ToxCast chemicals. Published emissions data for 31 SVOCs found in flooring materials, provided a training set where both chemical-specific physicochemical properties, article specific formulation properties, and experimental design aspects were available as modeling descriptors. A linear regression yielded R2- and p- values of approximately 0.62 and 3.9E-05, respectively. A similar model was developed based upon physicochemical properties alone, since article information is often not available for a given SVOC or product. This latter model yielded R2 - and p- values of approximately 0.47 and 1.2E-10, respectively. Many SVOCs are also used as additives (e.g. plasticizers, antioxidants, lubricants) in plastic food packaging. Migration of these chemicals into foods is a complex kinetic process; the speed of migration and ultimate partitioning of chemical depends on the properties of the food, the chemical migrant, and the packaging material. A linear regression model was developed for equilibrium chemical migration (mass/area) from publically-available data collected in a variety of foods and food simulants for different conditions (e.g. temperatures; polymer formulations). The regression yielded an R2=0.71; significant predictors included the initial concentration of the migrant in the packaging, chemical properties (logP; vapor pressure), temperature, and food type (e.g., fatty, aqueous). Migration predictions were combined with food intakes from the National Health and Nutrition Examination Survey to estimate screening-level exposures to over 1500 additives and contaminants potentially present in food packaging. This abstract does not necessarily reflect U.S. EPA policy.
