Genotoxicity of 2-[2-(acetylamino)-4-[bis(2-hydroxyethyl) amino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-6) and 4-amino-3,3′-dichloro-5,4′-dinitro-biphenyl (ADDB) in goldfish (Carassius auratus) using the micronucleus test and the comet assay

2-[2-(Acetylamino)-4-[bis(2-hydroxyethyl)amino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA6) and 4-amino-3,3-dichloro-5,4-dinitrobiphenyl (ADDB) are two compounds, which show strong multagenicity toward bacteria, that have been identified as major mutagens in river water in Japan. In the present study, we examined the genotoxicity of PBTA-6 and ADDB in goldfish (Carassius auratus) by the micronucleus test and single-cell gel electrophoresis (comet assay). The frequencies of micronuclei in gill cells gradually increased until 96 h after i.p. injection of PBTA-6 and ADDB at doses of 50 mg/kg body weight, and then decreased 144 h after injection. PBTA-6 induced micronuclei in gill cells dose-dependently at a dose range of 1-100 mg/kg body weight, giving significantly high frequencies at doses of 50 and 100 mg/kg body weight. On the other hand, no significant increase was observed in the peripheral erythrocytes of goldfish exposed to PBTA-6 or ADDB. In the comet assay, values of DNA tail moment and tail length in peripheral erythrocytes increased significantly until 6 h after the i.p. injection of PBTA-6 (50 mg/kg body weight), only to decrease by 9 h after injection. Both the DNA tail moment and tail length were dose-dependently increased by injections of PBTA-6 at doses ranging from I to 50 mg/kg. Significantly high values for tail moment and tail length were found in peripheral erythrocytes 3 h after an i.p. injection of ADDB and persisted for up to 6 It. These results show that both PBTA-6 and ADDB have genotoxic effects in goldfish. (C) 2004 Elsevier B.V. All rights reserved.