Bioavailability of the genotoxic components in coal tar contaminated soilsin Fischer 344 rats

The effect of chemical aging on the bioavailability and subsequent genotoxi city of coal tar (CT)-contaminated soils was evaluated in a 17-day feeding study using Fischer 344 male rats. Rats consumed a control diet or diets am ended with soil, 0.35% CT, or soil freshly prepared or aged for 9 months wi th 0.35% CT. Mild treatment-related microscopic lesions in liver tissue and elevated enzyme levels in serum were detected in all CT treatment groups. The P-32-postlabeling assay was employed to determine DNA adduct formation in treated animals. All CT treatment groups induced DNA adducts in both the liver and lung. Adduct levels were 3-fold higher in lung DNA compared to h epatic DNA. After correcting adduct levels for total ingested polycyclic ar omatic hydrocarbons (PAHs), a significant decrease (p < 0.05) in adduct lev els was observed in both CT/soil treatment groups compared to CT control in liver and lung DNA. Adduct profiles of P-32-postlabeled hepatic and lung D NA displayed several nonpolar DNA adducts that comigrated with PAH-adducted calf thymus DNA standards as determined through both thin-layer chromatogr aphy (TLC) and high-pressure liquid chromatography (HPLC), These results su ggest that soil, but not aging of contaminants in soil, decreases the bioav ailability of genotoxic components in CT, as evidenced by DNA adduct analys is.