Deposition, retention, and biological fate of inhaled benzo(a)pyrene adsorbed onto ultrafine particles and as a pure aerosol
The effect of ultrafine, airborne, carrier particles on the deposition, retention, and biological fate of inhaled polycyclic aromatic hydrocarbons (PAHs) was studied. Using a radiolabeled model PAH, (/sup 3/H)benzo(a)pyrene ((/sup 3/H)BaP), Fischer-344 rats were exposed by nose-only inhalation (30 min) to this compound, as a coating (15% by mass) on insoluble /sup 67/Ga/sub 2/O/sub 3/ particles or as a pure aerosol. These aerosols were produced by vapor condensation methods in a dynamic aerosol generation system. The concentrations of (/sup 3/H)BaP in the coated and homogeneous aerosols were 0.6 and 1.0 ..mu..g/liter of air, respectively, while the mass median diameter of both these aerosols was approximately 0.1 ..mu..m. Pulmonary retention of /sup 3/H radioactivity was longer in animals exposed to the (/sup 3/H)BaP coated on the /sup 67/Ga/sub 2/O/sub 3/ particles. The time required to clear 90% of the initial lung burden of /sup 67/Ga/sub 2/O/sub 3/-associated /sup 3/H radioactivity detected 30 min postexposure was approximately 1 day as compared to 4 hr for animals ex Tracheal clearance of 90% of the /sup 67/Ga/sub 2/O/sub 3/-associated /sup 3/H radioactivity required 1 day, while only 1.5 hr were required to clear the same percentage of /sup 3/H radioactivity from the tracheas of rats exposed to the pure (/sup 3/H)BaP aerosol. The rates of clearance of this /sup 3/H material to other tissues suggested that a substantial amount of the (/sup 3/H)BaP coated on /sup 67/Ga/sub 2/O/sub 3/ was cleared from lungs by mucociliary clearance and subsequent ingestion, whereas the majority of the pure (/sup 3/H)BaP aerosol was cleared by direct absorption into blood. In both cases, the ultimate fate of the majority of the (/sup 3/H)BaP and its metabolites was excretion in feces.
- Research Organization:
- Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM
- DOE Contract Number:
- AC04-76EV01013
- OSTI ID:
- 6094594
- Journal Information:
- Toxicol. Appl. Pharmacol.; (United States), Vol. 65
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
BENZOPYRENE
LUNG CLEARANCE
RETENTION
AEROSOLS
DEPOSITION
EXCRETION
EXPERIMENTAL DATA
GALLIUM 67
GASTROINTESTINAL TRACT
INHALATION
PARTICULATES
RATS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ANIMALS
AROMATICS
BETA DECAY RADIOISOTOPES
CLEARANCE
COLLOIDS
CONDENSED AROMATICS
DATA
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DISPERSIONS
ELECTRON CAPTURE RADIOISOTOPES
GALLIUM ISOTOPES
HYDROCARBONS
INFORMATION
INTAKE
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PARTICLES
RADIOISOTOPES
RODENTS
SOLS
VERTEBRATES
560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)
550501 - Metabolism- Tracer Techniques