A SUBACUTE INHALATION EXPOSURE EVALUATION OF A SCRUBBING SOLUTION USED IN PETROLEUM REFINERIES

The potential for subacute toxicity and neurotoxicity of a potassium c arbonate-based scrubbing solution used in petroleum refineries was eva luated in Sprague-Dawley Crl:CD BR rats. Exposures were to aerosols of a ''used'' scrubbing solution by whole-body inhalation, 6 h/d, for 27 consecutive days at target concentrations of 0 (filtered air-control) , 0.1, 0.2, or 0.4 mg/L (30 animals/sex/group). A functional observati on battery (FOB) and locomotor activities tests were conducted and mon itored. No apparent adverse effects were noted at any exposure level a s determined by clinical observations, food consumption, hematology, s erum chemistry, ophthalmologic observations, and gross pathology. Stat istically significant increases in lung weights were noted at all trea tment levels but returned to control values upon cessation of exposure except for the 0.4 mg/L female group. There were no significant chang es in other organ weights. Histopathologic findings were restricted to the respiratory tract and characterized by minimal to moderate epithe lial hyperplasia, epithelial necrosis, and cytoplasmic vacuolation at levels I and II of the nasal cavities. Lung bronchiolization and alveo lar macrophage infiltration were also observed. The respiratory-tract findings were considered a local response to the high alkalinity of th e test material as substantiated by the return to normal upon cessatio n of exposure. Exposure to scrubbing solution had no adverse effect on FOE endpoints and locomotor activity evaluations, drain weight and si ze, and neuropathologic examinations. In conclusion, inhalation exposu re to a used scrubbing solution aerosol for 21 d did not result in any persistent systemic toxicity or neurotoxicity in either male or femal e rats.