Lung cell exposure to secondary photochemical aerosols generated from OH oxidation of cyclic siloxanes

October 15, 2019

DOI: 10.1016/j.chemosphere.2019.125126

Autors

King BM1, Janechek NJ1, Bryngelson N1, Adamcakova-Dodd A2, Lersch T3, Bunker K3, Casuccio G3, Thorne PS2, Stanier CO4, Fiegel J5.

1 Department of Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA.
2 Department of Occupational and Environmental Health, The University of Iowa, 145 N. Riverside Dr., Iowa City, IA, 52242, USA.
3 RJ Lee Group, 350 Hochberg Road, Monroeville, PA, 15146, USA.
4 Department of Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA. Electronic address: charles-stanier@uiowa.edu.
5 Department of Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA. Electronic address: jennifer-fiegel@uiowa.edu.

 

Highlights
• Oxidative flow reactor used to study effects of secondary aerosols on lung cells.
• Nanoparticulate aerosols generated from OH oxidation of D5, a cyclic siloxane.
• Acute exposures to 54–116 ng/cm2 achieved using the air-liquid interface (ALI) system.
• Cytotoxic and proinflammatory effects marginal or absent at these doses.

 

Abstract
To study the fate of cyclic volatile methyl siloxanes (cVMS) undergoing photooxidation in the environment and to assess the acute toxicity of inhaled secondary aerosols from cVMS, we used an oxidative flow reactor (OFR) to produce aerosols from oxidation of decamethylcyclopentasiloxane (D5). The aerosols produced from this process were characterized for size, shape, and chemical composition. We found that the OFR produced aerosols composed of silicon and oxygen, arranged in chain agglomerates, with primary particles of approximately 31 nm in diameter. Lung cells were exposed to the secondary organosilicon aerosols at estimated doses of 54-116 ng/cm2 using a Vitrocell air-liquid interface system, and organic gases and ozone exposure was minimized through a series of denuders. Siloxane aerosols were not found to be highly toxic.

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