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Diesel exhaust is a pulmonary carcinogen in rats exposed chronically by inhalation

Journal Article · · Fundam. Appl. Toxicol.; (United States)
Male and female F344 rats were exposed 7 hr/day, 5 day/week for up to 30 months to automotive diesel engine exhaust at soot concentrations of 0.35, 3.5, or 7.0 mg/m3 or were sham-exposed to clean air. Rats were terminated at 6-month intervals to measure lung burdens of diesel soot and for histopathology. Other rats either died or were terminated after 30 months of exposure. Lungs were fixed, sectioned into 3-mm slices, and examined by a dissecting microscope to detect tumors. Lesions were stained and examined by light microscopy. Survival and body weight were unaffected by exposure. Focal fibrotic and proliferative lung disease accompanied a progressive accumulation of soot in the lung. The prevalence of lung tumors was significantly increased at the high (13%) and medium (4%) dose levels above the control prevalence (1%). Four tumor types, all of epithelial origin, were observed: adenoma, adenocarcinoma, squamous cyst, and squamous cell carcinoma. Logistic regression modeling demonstrated a significant relationship between tumor prevalence and both exposure concentration and soot lung burden. These results demonstrate that diesel exhaust, inhaled chronically at a high concentration, is a pulmonary carcinogen in the rat.
Research Organization:
Lovelace Biomedical and Environmental Research Institute, Albuquerque, NM
OSTI ID:
5844694
Journal Information:
Fundam. Appl. Toxicol.; (United States), Journal Name: Fundam. Appl. Toxicol.; (United States) Vol. 9:2; ISSN FAATD
Country of Publication:
United States
Language:
English