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Exploring the exposome with non-targeted analysis of house dust (2018 ACS)
Citation:
Ulrich, E., D. Mills, J. Sobus, J. McCord, K. Hibbert, AND N. Tulve. Exploring the exposome with non-targeted analysis of house dust (2018 ACS). 2018 ACS Spring Meeting, New Orleans, LA, March 18 - 22, 2018.
Impact/Purpose:
We conducted pilot studies using NTA approaches to 1) characterize some sources of variability in chemicals detected in house dust and 2) identify and understand differences between chemicals in dust in homes with and without children including chemical indicators (e.g., flame retardants) of non-chemical stressors (e.g., technology access).
Description:
The exposome encompasses the totality of exposures to all stressors for an individual over their life-course. Measuring and understanding the exposome is important to fully understand the origins of disease and ensure that chemicals in commerce are low risk. However, it is not feasible or practical to provide data for the tens- to hundreds-of- thousands of chemicals in existence and used in commerce with traditional targeted analytical techniques. Non-targeted analysis (NTA) uses unbiased approaches to measure as many chemicals as possible in a single analysis. We conducted pilot studies using NTA approaches to 1) characterize some sources of variability in chemicals detected in house dust and 2) identify and understand differences between chemicals in dust in homes with and without children including chemical indicators (e.g., flame retardants) of non-chemical stressors (e.g., technology access). Dust samples and QA samples (blanks, replicates, NIST SRM 2585) were extracted in methanol and analyzed using liquid chromatography (LC) with high resolution accurate mass (HRAM) quadrupole-time of flight (QTOF) mass spectrometry (MS). To address the first issue, we examined dust samples collected in 13 rooms from one home at 3 time points (collected 1-4 months apart). Samples were sieved into two size fractions (<150 μm and 150 μm-1 mm) and each was extracted three times and then analyzed in triplicate. Preliminary analysis has determined that the size fractions are quite similar, and do not contribute much variability. Additional sources of variability are currently being evaluated. To address the second issue, we examined dust samples collected in nine homes (4 without children, 5 with children). When home types were compared, there were a large (~1000) number of features that were either in higher abundance (> 4-fold) or unique in homes with children. Several chemicals also provided evidence of non-chemical stressors (e.g., caffeine- sleep related; sunscreens- outdoor activity; hesperidin- diet related). Because humans spend the majority of their time indoors, and children have increased exposures due to child specific activities and behaviors, it is critical to understand exposure to house dust and all of the chemicals contained therein.
