Residential Exposure of Young Children to SVOCsEPA Grant Number: R835642
Title: Residential Exposure of Young Children to SVOCs
Investigators: Stapleton, Heather , Webster, Thomas F. , Ferguson, P. Lee
Institution: Duke University , Boston University
EPA Project Officer: Klieforth, Barbara I
Project Period: September 1, 2014 through August 31, 2017 (Extended to August 31, 2018)
Project Amount: $900,000
RFA: New Methods in 21st Century Exposure Science (2013) RFA Text | Recipients Lists
Research Category: Safer Chemicals , Human Health , Health
We hypothesize that residues measured in children’s hand wipes will provide an improved measure of personal exposure to a wide range of semivolatile organic compounds (SVOCs) emitted from indoor sources. Furthermore we hypothesize that exposure levels will be related to chemical applications in specific consumer products commonly found in the home environment. To test these hypotheses we propose to: 1) Characterize SVOC sources in products by collecting surface wipes from consumer products (in the home) that may be potential sources of SVOCs (and other chemical additives) to the indoor environment (e.g. furniture, vinyl flooring, electronics, insulation, etc). 2) Characterize and quantify residential exposure of young children to SVOCs using hand wipes and determine how closely these measurements correlate with levels measured in paired samples of serum, urine, indoor air, and house dust from 50 children between the ages of 24-48 months of age. The hand wipes, air and dust samples will be analyzed for a suite of SVOC compounds using both targeted and nontargeted analytical methods. Additionally, we will: 3) Identify sources of variability in hand wipe measurements such as hand washing, lotions, etc.; 4) Examine the patterns of coexposure to multiple SVOCs (an important issue in the assessment of chemical mixtures); and 5) Compare our empirical results for SVOCs with predictions from indoor models.
We will recruit 50 families into our study. Paired samples of serum, urine, hand wipes, consumer product surface wipes, and house dust will be collected for 50 children between the ages of 2-4 in central North Carolina and analyzed for organic contaminants using both targeted (i.e. measuring selected chemicals) and non-targeted (i.e. broadband screening) approaches. A detailed questionnaire will be administered to collect information on diet, home characteristics and behavioral aspects of the children that may contribute to exposure (e.g., mouthing behaviors). Associations among all matrices will be examined, and particular attention will be given to investigating correlations between SVOC measures in consumer product surface wipes with SVOC exposure levels. Statistical analyses will be conducted to determine how well i) SVOCs measured in consumer products, dust, and air predict measured hand wipe levels and ii) the degree to which hand wipes (a measure of personal exposure) predict SVOC levels in serum and urine (biomarkers of exposure) compared to measurements in home air and dust (measurements in microenvironment). Data collected from this study will be compared to exposure models to evaluate the predictive power of the models.
As current knowledge regarding the occurrence, levels and even identity of SVOCs in consumer products is limited, our study will add substantially to that knowledge base. We anticipate observing significant associations among biomarkers of exposure, hand wipes and dust for a large number of SVOCs measured across a range of physicochemical properties. Results from this study will also provide the first data on novel SVOCs detectable in hand wipes and dust using high resolution mass spectrometry-based nontargeted analytical screening approaches. This aspect is particularly innovative and may provide insight into previously unknown or uncharacterized contaminant exposures in the home environment. Knowledge of patterns of joint exposures is a key research gap and this study will help improve our understanding of exposure to mixtures. We will also identify links between specific products in the home and children’s exposure levels. Lastly, our study will be used to update screening models for indoor behavior and exposure to SVOCs and to compare the predictions with our empirical data.