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2000
Conference Paper
Titel
Lung tumors in rats after repeated intratracheal instillation of coal dust
Abstract
Five coal-containing dusts from materials of the Ruhr coal mining area were applied to female Wistar rats by intratracheal instillation of a suspension of 6mg dust 10 or 20 times weekly. The content of SiO2 in two dusts from milled coal (lean coal and lower rich coal) was not detectable (means <0.1%) and ash content was low (5 and 6%). The other coal-containing dusts (fine fractions of dusts collected from the air in mines) contained more SiO2 (1.3%, 9%, 16.7%) and more ash (~40%, ~60%, 86%). The median metric diameters were between 1.8 and 4.0 nm and the density between 1.4 (milled coal) and 2.4g/mL (stone dust). The tumor response was dose-dependent. After treatment with the lower dose, malignant and/or benign lung tumors were found in 57-72% with the exception of 34% of the stone dust with 86% ash and 16.7% quartz. The results show that relatively coarse coal dusts with a lung burden of about 40mg induced unexpectedly high lung tumor rates wiht the sensitive intratracheal model. Taking earlier results into consideration, the volume of low toxic dusts seems to be more important for the tumor repsonse than particle size. The different quartz contents of the coal-containing dusts tested did not detectably influence the carcinogenicity.
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