ACUTE AND SUB-CHRONIC INHALATION EXPOSURES OF HAMSTERS TO NICKEL-ENRICHED FLY-ASH

One 6-hr inhalation exposure of hamsters to Ni-enriched fly ash (NEFA) aerosol (respirable aerosol concentration ∼200 μg/liter) deposited about 80 μg in the deep lung, of which 75 μg was still present 30 days postexposure. The animals tolerated the exposure well during the 30-day postexposure observation period. Two-month exposures of hamsters to NEFA or fly ash (FA) aerosols (∼185 μg/liter) resulted in a deep lung burden of about 5.7 mg, dark discoloration of lungs, heavily dustladen macrophages, and significantly higher lung weights than in controls, but only minimal inflammatory reaction and no deaths. There was no difference between NEFA and FA effects. The NEFA contained 9% Ni; FA contained 0.03% NI. The results of this study indicate low acute and subchronic toxicity and slow lung clearance of NEFA and FA. © 1979.