Effect of polycyclic aromatic hydrocarbons on somatic chromosomes of coal tar workers

The genotoxic effect of polycyclic aromatic hydrocarbons (PAHs) on somatic human chromosomes obtained from lymphocytes of 49 coal tar workers exposed to 26 micrograms/m3 benzo(a)pyrene, 16 mg/m3 benzene and 0.04 mg/m3 H2S in the ambient air, compared to equal numbers of matched controls breathing air containing 1 microgram/m3 benzo(a)pyrene, 1.5 mg/m3 benzene and 0.02 mg/m3 H2S, was investigated. The mitotic index (MI), chromosome aberrations (CAs), sister chromatid exchanges (SCEs) and satellite associations (SAs) were analysed. All the parameters showed a significant increase (p < 0.01 and 0.05) in the exposed individuals compared with the controls: viz MI, 4.59-7.92; CAs, 0.77-3.0; SCEs, 5.89-6.80; and SAs, 8.18-14.26. The occurrence of the DG type of satellite associations were highest and the 3D type lowest. The frequency of SCEs was highest in coal tar workers with an exposure period of 6-10 years. It is suggested that these results show PAH is genotoxic for humans.