Modeling accumulations of particles in lung during chronic inhalation exposures that lead to impaired clearance

Journal Article · Sun Jan 01 04:00:00 EST 1989 · Health Physics; (USA)

DOI:https://doi.org/10.1097/00004032-198907001-00007· OSTI ID:7166910

Wolff, R K; Griffith, Jr, W C; Cuddihy, R G; Snipes, M B; Henderson, R F; Mauderly, J L; McClellan, R O ^[1]

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1. Lovelace Inhalation Toxicology Research Institute, Albuquerque, NM (USA)

Chronic inhalation of insoluble particles of low toxicity that produce substantial lung burdens of particles, or inhalation of particles that are highly toxic to the lung, can impair clearance. This report describes model calculations of accumulations in lung of inhaled low-toxicity diesel exhaust soot and high-toxicity Ga2O3 particles. Lung burdens of diesel soot were measured periodically during a 24-mo exposure to inhaled diesel exhaust at soot concentrations of 0, 0.35, 3.5, and 7 mg m-3, 7 h d-1, 5 d wk-1. Lung burdens of Ga2O3 were measured for 1 y after a 4-wk exposure to 23 mg Ga2O3 m-3, 2 h d-1, 5 d wk-1. Lung burdens of Ga2O3 were measured for 1 y both studies using inhaled radiolabeled tracer particles. Simulation models fit the observed lung burdens of diesel soot in rats exposed to the 3.5- and 7-mg m-3 concentrations of soot only if it was assumed that clearance remained normal for several months, then virtually stopped. Impaired clearance from high-toxicity particles occurred early after accumulations of a low burden, but that from low-toxicity particles was evident only after months of exposure, when high burdens had accumulated in lung. The impairment in clearances of Ga2O3 particles and radiolabeled tracers was similar, but the impairment in clearance of diesel soot and radiolabeled tracers differed in magnitude. This might have been related to differences in particle size and composition between the tracers and diesel soot. Particle clearance impairment should be considered both in the design of chronic exposures of laboratory animals to inhaled particles and in extrapolating the results to people.

• OSTI ID: 7166910
• Journal Information: Health Physics; (USA), Journal Name: Health Physics; (USA); ISSN 0017-9078; ISSN HLTPA
• Country of Publication: United States
• Language: English

Related Subjects

550501 -- Metabolism-- Tracer Techniques
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AEROSOLS
ANIMALS
BIOLOGICAL ACCUMULATION
BIOLOGICAL MODELS
BODY
CHRONIC EXPOSURE
CLEARANCE
COLLOIDS
DIESEL ENGINES
DISPERSIONS
ELEMENTS
ENGINES
EXCRETION
EXHAUST GASES
FLUIDS
GALLIUM
GASEOUS WASTES
GASES
HEAT ENGINES
INHALATION
INTAKE
INTERNAL COMBUSTION ENGINES
ISOTOPE APPLICATIONS
ISOTOPES
LUNG CLEARANCE
LUNGS
MAMMALS
METALS
ORGANS
PARTICLE SIZE
PARTICLES
PARTICULATES
RADIOISOTOPES
RATS
RESPIRATORY SYSTEM
RODENTS
SIZE
SOLS
SOOT
TRACER TECHNIQUES
VERTEBRATES
WASTES