THE USE OF IN-VITRO DNA ADDUCT FORMATION TO ESTIMATE THE GENOTOXICITYOF RESIDUES AT CONTAMINATED SITES

Genotoxic carcinogens such as polycyclic aromatic hydrocarbons (PAHs) covalently bind to the bases in DNA to form adducts. The formation of DNA adducts is significant with respect to chemical carcinogenesis. Ma ny contaminated sites contain quanitities of carcinogens such as PAHs, and the evaluation of the genotoxicity of these soils has important i mplications for human risk assessment. DNA adducts can be formed using an in vitro system incorporating extracts from contaminated soils. Th e P-32-postlabelling assay is a sensitive technique for the detection of DNA adducts from complex mixtures of environmental carcinogens. The se techniques have been used to form and detect DNA adducts using soil s from a number of coal gasworks sites. The results show that the exte nt of adduct formation depends partially on the petroleum hydrocarbon content of samples, but also on other undetermined factors related to composition. While environmental weathering has been shown to effect t he PAH compostition of samples, this is not an important factor in con trolling the genotoxicity of samples as estimated by DNA adduct format ion.