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. 2022;34(11-12):340-349.
doi: 10.1080/08958378.2022.2114562. Epub 2022 Aug 25.

Automated crude oil vapor inhalation exposure system

Walter McKinney  1 , Mark C Jackson  1 , Brandon Law  1 , Jeffrey S Fedan  1
Affiliations

Automated crude oil vapor inhalation exposure system

Walter McKinney et al. Inhal Toxicol. 2022.

Abstract

Objective: Inhalation exposure systems are tools for delivering compounds (particles, vapors, and gases) under well-controlled conditions for toxicological testing. The objective of this project was to develop an automated computer-controlled system to expose small laboratory animals to precise concentrations of crude oil vapor (COV).Materials and Methods: Vapor from heated Deepwater Horizon surrogate oil was atomized into a fine mist then diluted with filtered air, then the air/droplet mixture was routed into an evaporation column with an high efficiency particulate air (HEPA) filter on its exit port. The HEPA filter was used to remove oil particles, thus ensuring only vapor would pass. The vapor was then introduced into a custom-built exposure chamber housing rats. A calibrated flame ionization detector was used to read the total volatile organic compounds (TVOC) in real time, and custom software was developed to automatically adjust the amount of oil entering the atomizer with a syringe pump. The software also controlled relative humidity and pressure inside the exposure chamber. Other exposure chamber environmental parameters, e.g. temperature and CO2 levels, were monitored. Four specific components within the COV were monitored during each exposure: benzene, toluene, ethylbenzene, and xylenes.Results: The TVOC vapor concentration control algorithm maintained median concentrations to within ±2 ppm of the target concentration (300 ppm) of TVOC during exposures lasting 6 h. The system could reach 90% of the desired target in less than 15 min, and repeat exposures were consistent and reproducible.Conclusion: This exposure system provided a highly automated tool for conducting COV inhalation toxicology studies.

Keywords: Crude oil vapor; VOC inhalation; deepwater horizon; exposure chamber; inhalation exposure.

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Figures

Figure 1.
Figure 1.
Crude oil inhalation exposure system diagram.
Figure 2.
Figure 2.
FID calibration data plot.
Figure 3.
Figure 3.
Exposure chamber diagram (24 rat capacity).
Figure 4.
Figure 4.
Custom software’s main screen.
Figure 5.
Figure 5.
GC-FID spectrum output from a typical crude oil vapor reading at 300 ppm TVOC.
Figure 6.
Figure 6.
CG-FID spectrum output from BTEX calibration gas.
Figure 7.
Figure 7.
Exposure chamber TVOC during feedback tuning.
Figure 8.
Figure 8.
(A). Typical exposure chamber TVOC concentration (A) and relative humidity (B) plots during a 6 h exposure.
Figure 9.
Figure 9.
Typical exposure chamber temperature (A) and CO2 levels (B) during a 6 h exposure.
See this image and copyright information in PMC

References

    1. Decker JR, Swannack RD, DeFord HS, Hayden GA. 2001. BEDAC,” an automated data acquisition and control system for inhalation exposure of small animals. Toxicol Sci 60(1, suppl):429.
    1. Fedan JS, Roberts JR, Barger M, Snawder JE, Schwegler-Berry D, Friend S, Leonard SS, Thompson JA, Jackson MC, Dozier AK, et al. 2022. Biological effects of inhaled crude oil vapor. II. Toxicol Appl Pharmacol 450:116154. - PubMed
    1. Fedan JS. 2022. Biological effects of inhaled crude oil vapor. I. Scope of the investigation. Toxicol Appl Pharmacol - PubMed
    1. Goldsmith WT, McKinney W, Jackson M, Law B, Bledsoe T, Siegel P, Cumpston J, Frazer D. 2011. A computer-controlled whole-body inhalation exposure system for the oil dispersant COREXIT EC9500A. J Toxicol Environ Health A 74(21):1368–1380. - PMC - PubMed
    1. Investigative Team, 2022. Biological effects of inhaled crude oil vapor. VII. Summary and significance. Toxicol Appl Pharmacol Revision submitted to journal. - PubMed

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