IDENTIFICATION OF A 2-PHENYLBENZOTRIAZOLE (PBTA)-TYPE MUTAGEN, PBTA-2, IN WATER FROM THE NISHITAKASE RIVER IN KYOTO

We previously isolated five mutagens, compounds I-V, in blue rayon-ads orbed materials from the Nishitakase River in Kyoto. The chemical stru cture of compound I, a major mutagen that accounted for 21% of the tot al mutagenicity, was determined to be thoxyethyl)amino]-5-methoxypheny l]-5-amino-7-bromo -4-chloro-2H-benzotriazole (PBTA-1). Compound II wa s also a major mutagen and accounted for 17% of the total mutagenicity . In this study, a large quantity (1.2 mg) of compound II was isolated from adsorbate to 27 kg of blue cotton, and its UV, mass, and H-1 NMR spectra were analyzed. On the basis of the spectral data, compound II was deduced to be the PBTA-1 analogue lamino]-5-methoxyphenyl]-5-amin o-7-bromo-4-chloro- 2H-benzotriazole (PBTA-2). As with PBTA-1, PBTA-2 was synthesized from an azo dye by reduction and chlorination. Since a ll of the spectra of PBTA-2 coincided with those of compound II obtain ed from river water, compound II was concluded to be PBTA-2. PBTA-2 is a newly identified potent mutagen, which induces 93 000 and 3 200 000 revertants of Salmonella typhimurium TA98 and YG1024 per microgram, r espectively, in the presence of S9 mix. Like PBTA-1, PBTA-2 may also b e produced from an azo dye during industrial processes in dyeing facto ries and treatment at sewage plants.