Submarine exposure guideline recommendations for carbon dioxide based on the prenatal developmental effects of exposure in rats

Journal Article · 03 December 2018 · Birth Defects Research

DOI: https://doi.org/10.1002/bdr2.1417 · OSTI ID:1786134

Howard, William R.  ^[1]; Wong, Brian ^[2]; Yeager, Kimberly S. B. ^[3]; Stump, Donald G. ^[4]; Edwards, Tammye ^[4]; Arden James, Richard ^[2]; Goodwin, Michelle R. ^[2]; Gargas, Michael L. ^[1]

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1. Naval Medical Research Unit Dayton, Wright Patterson AFB Dayton Ohio
2. Henry M. Jackson Foundation for the Advancement of Military Medicine Wright Patterson AFB Dayton Ohio
3. Oak Ridge Institute for Science and Education Oak Ridge Tennessee
4. Charles River Laboratories Ashland Ohio

Background To protect crewmember health, the U.S. Navy sets exposure limits for more than 200 components of submarine atmospheres. The addition of females to nuclear submarines required a reevaluation of these exposure limits, originally established for all‐male crews. In the case of carbon dioxide (CO ₂ ), the only available data suitable for deriving an exposure limit were from a 2010 study sponsored by the British Royal Navy that reported a debatable interpretation casting doubt on whether current U.S. Navy exposure limits served to protect fetal developmental health. Methods About 120 time‐mated female Sprague–Dawley rats (Crl: CD[SD]) were exposed to CO ₂ at levels of 1.5%, 2.0%, 2.5%, and 3.0% from gestation days 6 to 20. Dams were euthanized and fetuses were examined. Results Findings with implications for exposure limits for CO ₂ during pregnancy were an increased mean litter proportion of early resorptions and a lower mean litter proportion of viable fetuses in the 3.0% CO ₂ group. Conclusion The results yield a No Observed Adverse Effect Level (NOAEL) of 2.5% and a Lowest Observed Adverse Effect Level (LOAEL) of 3.0%. The results reasonably allow a point of departure of 2.5% CO ₂ for deriving an exposure recommendation. An interspecies uncertainty factor was applied to derive a recommended 90‐day continuous exposure limit (CEL) of 0.8% for CO ₂ . As reproductive endpoints that are developmental in nature must be assumed to result from a single exposure at a critical point during gestation, it is further recommended that the 24‐hr emergency exposure limit (EEL) also be 0.8%.

• Sponsoring Organization: USDOE
• OSTI ID: 1786134
• Journal Information: Birth Defects Research, Journal Name: Birth Defects Research Journal Issue: 1 Vol. 111; ISSN 2472-1727
• Publisher: Wiley Blackwell (John Wiley & Sons)Copyright Statement
• Country of Publication: Country unknown/Code not available
• Language: English