[Studies on the tumourigenicity of extracts and their fractions of airborne particulates with the subcutaneous test in the mouse (author's transl)].

Abstract

Airborne particulate matter was collected on filters at various times in Duisburg, Duesseldorf, Muenster and in 2 rural areas. After extraction with organic solvents the extract was partly fractionated and analyzed for BaP and 7 other polycyclic aromatic hydrocarbons (PAH). The carcinogenicity was examined with the subcutaneous test using 7000 mice in total. The amount of extract required was relatively small. Extracts from suspended matter with a BaP content of 0.37 to 1.1 microgram BaP brought about tumour rates in the range of 30%. On account of the results the following can be concluded: 1. The total extract of atmospheric particulates results in definite dose-response relationship, when the part of the compounds not belonging to the PAH is rather low. 2. The PAH fractions derived from the suspended matter collected in different cities show the same carcinogenic potency, when they are adjusted to the same BaP level by means of concentration or dilution. 3. The PAH bear the most important share with respect to the carcinogenic potency of an extract from suspended matter. 4. Numerous compounds (polar substances) which are not classed with the PAH are carcinogenic to some extent, partly they are able to inhibit the carcinogenic effect. 5. The dose-response relationship of BaP is strongly leveled off in general when all the substances of an extract are present. That means when the dose of an extract is low, the importance of BaP becomes less. Therefore a fixed ratio concerning the effect of BaP within an extract cannot be given. It has to be examined in particular, which PAH and non-PAH are necessary to analyse in order to describe the carcinogenic effect due to an extract from airborne particulates. Much more attention is to be payed to the polar substances.