Effects of single and repeated exposures to thermo-oxidative degradation products of poly(acrylonitrile-butadiene-styrene) (ABS) on rat lung, liver, kidney, and brain.

Male Wistar rats were exposed to thermo-oxidative degradation products of heated poly(acrylonitrile-butadiene-styrene) (ABS). The exposures were conducted once, three times or ten times (5 nights/week, 6 h/night) in the nighttime. The degradation products included styrene, various nitriles, aldehydes, acids, and a significant aerosol fraction. The oxygen concentration in the exposure chamber was constantly above 20%. The shortest exposures caused a significant reduction of the 0-deethylation activity in lung and kidney but not in liver, as well as a decrease in tissue reduced glutathione concentration in liver and kidney but not in lung. These effects well-nigh disappeared during the two-week exposure. In these rats the cerebral glutathione was below the control range. Superoxide dismutase activity increased in liver and brain during the three-day exposure. In liver the activity reached the control value after the two-week exposure but the cerebral activity was significantly lower than in controls. The complex mixture of noxious compounds in the ABS fumes does not readily allow identification of causative agents. Nitrile-dependent histotoxic, peroxidative and reactive metabolite mediated mechanisms may be involved.