Contribution of polycyclic aromatic hydrocarbons and polar polycyclic aromatic compounds to the carcinogenic impact of flue gas condensate from coal-fired residential furnaces evaluated by implantation into the rat lung.

ABSTRACT

For identification of the substances chiefly responsible for the carcinogenic action of the emission condensate from coal-fired residential furnaces, the implantation method was used as a carcinogen-specific bioassay for comparison of the carcinogenic effect of various fractions with that of a total sample of flue gas condensate tested in 2 or 3 different doses. After implantation into the lungs of Osborne-Mendel rats, the condensate from coal-fired residential furnaces, a fraction containing polycyclic aromatic hydrocarbons (PAHs) and thiaarenes [sulfur-containing polycyclic aromatic compounds (S-PACs)] with 4-7 rings, as well as fraction containing more polar polycyclic aromatic compounds (PACs) and PAHs with higher molecular weight, induced lung carcinomas and sarcomas. According to probit analysis, the fraction containing PAHs plus S-PACs with 4-7 rings accounted for about 68.2% of the total carcinogenicity of flue gas condensate, whereas the fraction containing more polar PACs and higher PAHs accounted for about 54.6%. All other fractions, such as nonaromatic compounds and PACs with 2 and 3 rings, constituting about 70% of the weight of the total condensate, seemed not to be carcinogenic. Only 1.4% of the total carcinogenicity of the flue gas condensate was found to be attributable to the amount of benzo[a]pyrene (CAS 50-32-8) present in the condensate (1.14 mg/g condensate). The contribution of more than 100% of both active fractions to the total carcinogenicity (68.2 and 54.6%) may suggest an interrelation of the fractions.