Neurotoxic effects of the oxidative thermal degradation products form low density polyethylene

Adult male Wistar rats were exposed for 2–5 weeks, 6 h nightly, 5 nights a week, to oxidative thermal degradation products of low density polyethylene derived by heating (325°C) under an airstream in a tube oven. Chemical analysis of the degradation products in the gaseous fraction revealed a wide variety of potentially toxic molecules which included carbon monoxide (<20 ppm), formaldehyde (1.4 ppm), acrolein (0.5 ppm) and various other aldehydes (total concentration 18 ppm expressed as formaldehyde). The mean oxygen concentration was 20%. The total particulate fraction amounted to 8 mg m −3 . The latter particles might have caused the detected discoloration of the rat fur. Similarly this contamination might have been the cause of a very significant increase in the duration and frequency of preening of the rats. The neurochemical effects associated with the exposure included an increase in the cerebral RNA concentration as well as initial increase in the glycosylation of cerebral protein in vitro. NADPH‐diaphorase activity was below the control range throughout the exposure while the superoxide dismutase activity displayed an increasing trend five weeks after the beginning of the experiment. The latter effects were taken as a response to potentially harmful molecules in the brain whereas the effects on the RNA and glycosylation might have resulted from a more peripheral nervous irritation.