ABSTRACT A petroleum-derived hydrocarbon mixture@ API No. 83-08@ was evaluated for its acute inhalation toxicity. Five young adult rats of each sex were exposed to a target aerosol concentration of 5.0 milligrams/liter (mg/L) for 4 hours (Phase I). No animals died during the exposure to a time weighted average (TWA) concentration of 5.06+0@29 mg/L; however@ three males and one female died during the 14 day observation period@ necessitating conduct of Phase II in an attempt to define the LC50 of the test material aerosols. Five additional groups of five male and five female rats each were exposed to target concentrations from 0 (air only control) to 7.5 mg/L. Aerosol was generated using a DeVilbiss No. 40 nebulizer and administered in the breathing air of the animals utilizing dynamic whole-body exposure methods. During pre-exposure atmosphere characterization tests@ it was shown that API No. 83-08@ when generated using this method@ produced an atmosphere that consisted entirely of aerosols. Analysis of aerosol concentrations during animal exposures was performed gravimetrically and yielded TWA concentrations of 0@ 2.34@ 3.47@ 6.34 and 7.29 mg/L. No control animals died@ but one male at 2.34 mg/L@ one female at 3.47 mg/L and all ten animals at 7.29 mg/L succumbed one to two days post exposure to API No. 83-08; a number of animals died at intermediate concentrations. Individual and mean body weight gains were depressed in dose related fashion following exposure to the test material. Histopathological examination of the lung tissues yielded dose related morphological changes consistent with hydrocarbon toxicity. An LC50 of 4.65 mg/L was calculated for both male rats and combined male and female rats. The 95% confidence limits of this LC50 for the combined sexes were 3.89 to 5.55 mg/L@ The female data alone were insufficient to calculate an LC50 value.
API PUBL 33-30444-1986 history
1986API PUBL 33-30444-1986 ACUTE INHALATION TOXICITY EVALUATION IN RATS API 83-08 LIGHT CATALYTICALLY CRACKED DISTILLATE (CAS 64741-59-9)