title: A computer-controlled whole-body inhalation exposure system for the oil dispersant COREXIT EC9500A.
abstract: An automated whole-body inhalation exposure system capable of exposing 12 individually housed rats was designed to examine the potential adverse health effects of the oil dispersant COREXIT EC9500A, used extensively during the Deepwater Horizon oil spill. A computer-controlled syringe pump injected the COREXIT EC9500A into an atomizer where droplets and vapor were formed and mixed with diluent air. The aerosolized COREXIT EC9500A was passed into a customized exposure chamber where a calibrated light-scattering instrument estimated the real-time particle mass concentration of the aerosol in the chamber. Software feedback loops controlled the chamber aerosol concentration and pressure throughout each exposure. The particle size distribution of the dispersant aerosol was measured and shown to have a count median aerodynamic diameter of 285 nm with a geometric standard deviation of 1.7. The total chamber concentration (particulate + vapor) was determined using a modification of the acidified methylene blue spectrophotometric assay for anionic surfactants. Tests were conducted to show the effectiveness of closed loop control of chamber concentration and to verify chamber concentration homogeneity. Five automated 5-h animal exposures were performed that produced controlled and consistent COREXIT EC9500A concentrations (27.1 ± 2.9 mg/m(3), mean ± SD).
authors.affiliation: National Institute for Occupational Safety and Health, Health Effects Laboratory Division, Pathology and Physiology Research Branch, Morgantown, West Virginia 26505, USA. Wbg4@cdc.gov
authors.forename: William Travis
authors.initials: WT
authors.lastname: Goldsmith
authors.forename: Walter
authors.initials: W
authors.lastname: McKinney
authors.forename: Mark
authors.initials: M
authors.lastname: Jackson
authors.forename: Brandon
authors.initials: B
authors.lastname: Law
authors.forename: Toni
authors.initials: T
authors.lastname: Bledsoe
authors.forename: Paul
authors.initials: P
authors.lastname: Siegel
authors.forename: Jared
authors.initials: J
authors.lastname: Cumpston
authors.forename: David
authors.initials: D
authors.lastname: Frazer
mesh_terms: D000336:Aerosols; D000818:Animals; D045703:Emulsifying Agents / Q000633:toxicity*; D052918:Environmental Restoration and Remediation / Q000009:adverse effects*; D019570:Inhalation Exposure / Q000009:adverse effects*; D008055:Lipids / Q000633:toxicity*; D008297:Male; D023421:Models, Animal; D059392:Petroleum Pollution; D051381:Rats; D017207:Rats, Sprague-Dawley; D012984:Software; D018675:Toxicity Tests / Q000295:instrumentation / Q000379:methods*
chemical_list: D000336:Aerosols; D045703:Emulsifying Agents; D008055:Lipids; C470995:corexit 9500