The study summarizes the results of an evaluation of mutagenicity of heterogeneous complex mixtures of substances, the main mutagenic component of which consists of polycyclic aromatic hydrocarbons. The testing was performed using bacterial assays of mutagenicity – the SOS chromotest and the S. typhimurium His-test (in modifications without and with metabolic activation in vitro). It was found that samples of tested tar mixtures (crude tar, pitch, anthracene oils III and II, granulated pitch and some of its extraction portions) induced SOS repair functions and frameshift mutations in tests with metabolic activation. Some of samples as tar, pitch and anthracene oils III, granulated pitch and two its extraction portions – LRAC and LRBe – induced also frameshift mutations, and SOS repairs in tests without the metabolic activation. In one sample – LRBe – the ability to induce mutations in all variants of both tests, was also proved. The evaluation of mutagenicity of fly ashes showed that differences in the mutagenic activity of samples can be directly dependent on the extraction method chosen and on the type of extraction agent used. The study results demonstrate that the bacterial tests Salmonella typhimurium His- and the SOS chromotest are uninterchangeable and quite independent. Both tests can be used for orientative screening for genotoxicity in a wide range of various complex mixtures arising from industrial production and contaminating the environment.

        Key words: polycyclic aromatic hydrocarbons, mutagenicity, Ames test, SOS chromotest.