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1987
Journal Article
Titel
Carcinogenicity studies on fibres, metal compounds and some other dusts in rats
Abstract
About 50 dusts were examined on their carcinogenicity in rats mainly after intraperitoneal injection and some after intratracheal instillation. In the i.p. test, very low doses between 0.05 and 0.5 mg asbestos led to tumour incidences of about 20 to 80%. Polyvinyl-pyridine-N-oxide prolonged the tumour latency after injection of actinolite. 60 mg attapulgite from three sources with short fibre lengths were not shown to be carcinogenic but an attapulgite sample with longer fibres had a moderate effect. Relatively thick rock and ceramic fibres (median>1µm) induced tumours, but slag and wollastonite fibres did not, probably because of their better solubility. Intratracheal instillation of glass microfibres (20x0.5 mg) led to lung tumours in 5 to 35 rats (0 in control). The carcinogenic potency of an in organic fibre depends on its size and persistency, and possibly also on other properties, especially on the surface. Nickel powder, nickel oxide, nickel subsulfide and cadmium sulfide were a ll found to be carcinogenic in the two tests. Cadmium chloride and cadmium oxide could only be administrated in very slow doses because of their high acute toxicity. A high amount of magnetite (15x15 mg i.tr.) led to an unexpected lung tumour incidence of 69%. The i.p. test in rats proved to be very sensitive for detecting the carcinogenic potency of non-acute toxic natural and man-made mineral dusts as well as metal compounds. This means that, if a high dose of one of these dusts dues not induced tumours in this test, no suspicion of carcinogenic potency can be substantiated.