Accession Number:

ADA256344

Title:

Metabolite Identification of Halon Replacement Compounds.

Descriptive Note:

Final rept. Mar 1991-Mar 1992,

Corporate Author:

MANTECH ENVIRONMENTAL TECHNOLOGY INC DAYTON OH

Report Date:

1992-06-01

Pagination or Media Count:

34.0

Abstract:

Halon 121 1 is currently being used by the U.S. Air Force as a flight line fire extinguishant. Because of health and environmental concerns over ozone depletion, Halon 1211 must be phased out by the year 2000. Before all interim replacement can be chosen, the toxicity of prospective candidates needs to be evaluated. This study has investigated the metabolism of the Halon replacement candidates perfluorohexane PFH and the hydrochlorofluorocarbons HCFCs HCFC- 123, HCFC-124, and HCFC-142b. Fischer 344 and Sprague-Dawley rats were exposed via inhalation to a 1 atmosphere for 2 h. Tissues were analyzed for volatile metabolites, and urine was analyzed for fluoride and carboxylic acid metabolites. Animals exposed to HCFC-123 or IICFC-124 excreted trifluoroacetic acid in their urine. The presence of trifluoroacetic acid indicates oxidative metabolism of HCFC-123 and IICFC-124. Increased fluoride was found in the urine of rats exposed to HCFC-124. HCFC-142b was metabolized to chlorodifluoroacetic acid, which was found in the urine of exposed rats. Fischer 344 and Sprague- Dawley rats exposed to HCFC-123 had small amounts of HCFC-133a and 2-chloro-1,1- difluoroethylene in liver tissue. The identification of HCFC-133a and 2-chloro- 1,1-difluoroethylene following exposure indicates reductive metabolism of HCFC- 123. No metabolites of PFH or Halon 1211 were identified in these investigations. Rats exposed to Halon 1211 had slightly elevated bromide levels in their urine compared to control values. Gas Chromatography, Gas ChromatographyMass Spectrometry, Halocarbons, Halon 121 1, HCFC-123, HCFC-124, HCFC-142b, Hydrochlorofluorocarbons HCFCs, Inhalation Exposure, Metabolism, Metabolite Analysis, Perfluorinated Hydrocarbons, Perfluorohexane.

Subject Categories:

  • Biochemistry
  • Organic Chemistry
  • Safety Engineering

Distribution Statement:

APPROVED FOR PUBLIC RELEASE