A whole body inhalation exposure system for the oil dispersant COREXIT 9500 with pulmonary function results from an initial set of exposures with rats.
Goldsmith-WT; McKinney-WG; Jackson-MC; Reynolds-JS; Cumpston-J; Frazer-DG
Toxicologist 2011 Mar; 120(Suppl 2):502
In response to the Deepwater Horizon oil spill, millions of gallons of chemical dispersant (mainly COREXIT 9500) were sprayed or pumped into the oil to accelerate the dispersal process. To examine the health effects of inhaled dispersants, an automated whole body inhalation exposure system was designed. COREXIT 9500 was placed in a glass syringe. Since the dispersant settled over time, a Teflon magnetic stir bar was also positioned in the syringe and a spinning magnet was employed to continually mix the liquid. A syringe pump injected the dispersant into an atomizer where droplets were formed and mixed with clean, dry air pressurized at 35 PSI. The aerosol was mixed with diluent air that was regulated with a mass flow controller (MFC). The diluted aerosol then was passed into a custom stainless steel and acrylic exposure chamber with 12 individually housed rats. Exhaust air was HEPA filtered and then run through a MFC attached to a vacuum source. A pressure transducer was used to monitor chamber pressure. A light scattering instrument (LSI) estimated the real-time particle mass concentration of the aerosol in the chamber. Gravimetric samples were used to calibrate the LSI. A custom software GUI was developed to record and control parameters during the exposures. Software feedback loops controlled the chamber aerosol concentration and pressure during exposures. Particle size of the dispersant aerosol was measured and shown to have a number peak at 271 nm and a mass peak at 961 nm. Chamber concentration homogeneity was established by placing multiple gravimetric samplers in various parts of the chamber during the same time period. Three individual exposures were conducted in which Sprague Dawley rats were exposed to 15 mg/m3 of COREXIT 9500 for 5 hours. Breathing rate and specific airway resistance comparisons between exposed (n=36) and control (n=36) animals showed no significant change immediately post, 1 day post and 7 days post exposure.
Biological-effects; Cell-biology; Inhalation-studies; Laboratory-animals; Laboratory-testing; Lung; Lung-cells; Lung-function; Lung-irritants; Pulmonary-function-tests; Pulmonary-system; Respiratory-function-tests; Animals; Animal-studies; Pulmonary-system-disorders; Respiratory-system-disorders
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The Toxicologist. Society of Toxicology 50th Annual Meeting and ToxExpo, March 6-10, 2011, Washington, DC