Studies on the susceptibility of various organs of zebrafish (Brachydanio rerio) to benzo(a)pyrene-induced DNA adduct formation

The susceptibility of various fish organs to polycylic aromatic hydrocarbons(PAHs)-induced DNA adduct formation was studied in zebrafish using benzo(a)pyrene as the representative carcinogenic PAH. Following exposure of fish to waterbome BaP at 0.2 mg/L for 3 days and at lmg/L for 4 days, 32P-postlabling analysis indicated that the adduct levels in intestine,liver, brain, and testis DNA were 13.3 ± l.2, 4.3 ± 2.5, 3.8 ± 0.5, and 0.2 0.l adducts per 108 nucleotides, respectively. When zebrafish were treated with BaP at 0.02 mg/L for 3 ±days and at 0.l mg/L for 4 days, a significant increase in the level of bulky adducts was detected only in intestine DNA (0.28 t 0.06 adduct / 108 nucleotides), and no adduct spots were observed for DNA isolated from other organs. Our data suggest that the fish intestine is a more sensitive target organ than the liver for biomonitoring the presence of carcinogenic PAHs in the aquatic enviroment, especially when PAHs are present at low levels.