Risk assessment of laboratory rats and mice chronically exposed to formaldehyde vapors
Experimental data from the Chemical Industry Institute of Toxicology (CIIT) are used to estimate the risk of squamous cell carcinoma of the nasal cavity in Fischer 344 (F344) rats over a range of ambient air concentrations of formaldehyde that includes current exposure guidelines for the workplace and home. These values are presented as a best estimate envelope obtained from five mathematical dose-response formulations. The response of Sprague-Dawley (SD) rats dosed at 15 ppm in a separate study at New York University is consistent with the predicted lifetime response for F344 rats at a slightly lower concentration (13-14 ppm). A dose-related mortality effect beyond what is attributable to the occurrenece of nasal carcinomas is found in F344 rats at all CIIT exposure levels (2,6, and 155 ppm). There is no evidence of a mortality effect in B6C3F1 mice of the CIIT study, and data for SD rats of the NYU experiment are inconclusive. In the CIIT study, rats exposed to 15 ppm exhibited a high incidence of nasal cavity squamous cell carcinomas and polypoid adenomas. Polypoid adenomas were also observed with increased incidences at 2 ppm and 6 ppm. Statistical comparisons with matched controls, and the low historical rate of spontaneous occurrence both suggest that polypoid adenomas may be a risk to F344 rats at exposure levels below the current Occupational Safety and Health Administration (OSHA) standard of 3 ppm. Squamous cell carcinomas were observed in two mice exposed to 15 ppm. This finding may be biologically significant since this tumor is rare and has not been previously reported in 4932 untreated B6C3F1 mice from recent National Toxicology Program (NTP) feeding studies.
- Research Organization:
- Chapel Hill, NC
- OSTI ID:
- 6926658
- Journal Information:
- Risk Anal.; (United States), Vol. 5:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
FORMALDEHYDE
BIOLOGICAL EFFECTS
MICE
CHRONIC EXPOSURE
RISK ASSESSMENT
RATS
ADENOMAS
BIOLOGICAL MODELS
CARCINOGENESIS
CARCINOMAS
CHRONIC INTAKE
DOSE-RESPONSE RELATIONSHIPS
HEALTH HAZARDS
HUMAN POPULATIONS
INHALATION
MORTALITY
NOSE
THERMAL INSULATION
ALDEHYDES
ANIMALS
BODY
BODY AREAS
DISEASES
FACE
HAZARDS
HEAD
INTAKE
MAMMALS
NEOPLASMS
ORGANIC COMPOUNDS
PATHOGENESIS
POPULATIONS
RESPIRATORY SYSTEM
RODENTS
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology
560300 - Chemicals Metabolism & Toxicology