Pilot study published on chemicals and bacteria in house dust.

In October 2017, Dr. Rich Corsi came to visit Oregon for two weeks during a sabbatical from the University of Texas, Austin. During his stay, Rich and I, and other BioBE/ESBL researchers chatted about doing a pilot study that would bring UT’s indoor chemistry work together with BioBE’s indoor microbial work.

Since we began our collaboration in the fall of 2017, only one of the research team is still in their original position (Jeff Kline at ESBL)! Rich Corsi, Ying Xu, and myself have all gone on to faculty positions elsewhere, graduate student Chenyang Bi defended and started a post-doc position, and the two undergrads working with me, Susie Nunez and Samantha Velazquez, graduated and went on to other things! Science collaborations work best when they can stand the test of time and geography. The benefit to everyone moving around is that you are able to hold collaboration meetings in new and exciting places each time.

In addition to the literature review we collaborated on, we eventually did get a research pilot running, and it has now been published in PeerJ!

Accumulation of di-2-ethylhexyl phthalate from polyvinyl chloride flooring into settled house dust and the effect on the bacterial community.

Samantha Velazquez1, Chenyang Bi 2,3, Jeff Kline 1,4, Susie Nunez1, Richard Corsi 3,5, Ying Xu 3,6, Suzanne L. Ishaq1,7*


1 Biology and the Built Environment Center,  University of Oregon, Eugene, OR, 97403

2 Department of Civil Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (current)

3 Department of Civil, Architectural and Environmental Engineering, University of Texas, Austin, TX 78712

4 Energy Studies and Buildings Laboratory, University of Oregon, Eugene, OR, 97403

5 Fariborz Maseeh College of Engineering and Computer Science, Portland State University, Portland, OR 97207 (current)

6 Department of Building Science, Tsinghua University, 100084, Beijing, P. R. China (current)

7 School of Food and Agriculture, University of Maine, Orono, ME 04469 (current)


Di-2-ethylhexyl phthalate (DEHP) is a plasticizer used in consumer products and building materials, including polyvinyl chloride flooring material. DEHP adsorbs from material and leaches into soil, water, or dust, and presents an exposure risk to building occupants by inhalation, ingestion, or absorption.  A number of bacterial isolates are demonstrated to degrade DEHP in culture, but bacteria may be susceptible to it as well, thus this study examined the relation of DEHP to bacterial communities in dust.  Polyvinyl chloride flooring was seeded with homogenized house dust and incubated for up to 14 days, and bacterial communities in dust were identified at days 1, 7, and 14 using the V3-V4 regions of the bacterial 16S rRNA gene.  DEHP concentration in dust increased over time, as expected, and bacterial richness and Shannon diversity were negatively correlated with DEHP concentration.  Some sequence variants of Bacillus, Corynebacterium jeddahense, Streptococcus, and Peptoniphilus were relatively more abundant at low concentrations of DEHP, while some Sphingomonas, Chryseobacterium, and a member of the Enterobacteriaceae family were relatively more abundant at higher concentrations.  The built environment is known to host lower microbial diversity and biomass than natural environments, and DEHP or other chemicals indoors may contribute to this paucity.

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