Subchronic inhalation study of pigmented polymer in rats

As part of a long-term investigation, a subchronic inhalation study of a pigmented polymer fraction was conducted by exposure of groups of SPF F-344 rats for six hours/day, five days/week for 13 weeks. The test material is a special 9000-type xerographic toner enriched about 10-fold in respirable size particles such that it is about 35% respirable according to AGGIH criteria. The nominal aerosol exposure concentrations were 0, 1.0, 4.0, 16.0 and 64.0 mg/cubic meters. The animals tolerated the exposure conditions well; no unscheduled deaths occured. Body weight, clinical chemistry values, food consumption and organ weights were normal with the exceptions noted for the highest exposure group. Constant body weight and clinical chemistry values, slight decrease in food consumption and about 50% increase in lung weight were observed in the highest exposure group. Histopathological examination of the lungs indicated a dose related increase of particle accumulation and macrophage recruitment. A very slight degree of septal thickening of the alveolar structure was noted in the highest exposure groups