The mutagenic activity of coal tar

: Genotoxicity of tar samples collected at the Kemerovo and Altai by-product coke plants has been studied, the contribution of benz(a)pyrene (BP) into the total mutagenic activity of extracts being estimated. Both direct and indirect mutagenicity of the samples is determined in the Ames test. A direct mutagenic effect of coal tar may be attributed neither to the BP action nor to other polycyclic aromatic hydrocarbons. The onset of the His revertant induction in Salmonella typhimurium strains Ta 100 and TA 97 treated with the coal tar activated by the S-9 mixture is observed in doses containing BP an order lower than threshold of its activity found in sole experiment. The highest mutagenic effect of the activated coal tar is observed at a dose containing the minimal active sole dose of BP (0.72-1.12 micrograms per plate).