DNA ADDUCTS IN CARP EXPOSED TO ARTIFICIAL DIESEL-2 OIL-SLICKS

In attempts to mimic field exposure, oil slicks prepared from diesel-2 oil/water emulsions were poured onto the surface of water in tanks prepared fresh every day and liver DNA adducts were analyzed by P-32-postlabeling in carp free-swimming in these tanks. 'Clusters' of lipophilic DNA adducts were detected, with five major and numerous minor adducts. Essentially a similar adduct pattern was found in the liver DNA of carp exposed to crude oil-polluted water. Diesel-2 adduct induction was observed slowly with a steady increase to > 3000 amol/mug DNA at day 12. After this time fish were transferred to clean water. Adduct levels continued to increase through day 17 (almost-equal-to 10,000 amol/mug DNA) despite the cessation of exposure, but a 30% and 80% decline was evident at day 22 and day 27, respectively. All major adducts were distinct from the known benzo[a]pyrene diolepoxide-dG. These results indicate that diesel-2 oil can cause extensive DNA damage in carp in vivo and the damage accumulates proportionately with time of exposure.