ISOLATION AND CHEMICAL-STRUCTURAL DETERMINATION OF A NOVEL AROMATIC AMINE MUTAGEN IN WATER FROM THE NISHITAKASE RIVER IN KYOTO

Water samples from the Nishitakase River in Kyoto, Japan, especially t aken at sites below sewage plants, show significantly high mutagenicit y in the Ames test. In the present study, mutagens in the river water were adsorbed to 24 g of blue rayon, extracted, and separated by HPLC on ODS columns. Five mutagenic compounds (I-V) were isolated, and they accounted for 21%, 17%, 11%, 12%, and 6%, respectively, of the total mutagenicity of the blue rayon-adsorbed materials. With compound I obt ained from adsorbate to 24 g of blue rayon as a marker, a large quanti ty (1.1 mg) of mutagenic compound I was isolated by Sephadex LH-20 col umn chromatography and HPLC on ODS columns from material adsorbed to 2 7 kg of blue cotton. X-ray crystal analysis was carried out with the d ebrominated derivative of compound I. Based on this X-ray crystallogra phy data and the UV, mass, and H-1-NMR spectra of both the derivative and compound I, the structure of compound I was determined to be 2-[2- (acetylamino) yphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA -1). PBTA-1 is a newly identified potent mutagen, inducing 1 200 000 r evertants of Salmonella typhimurium YG1024 per microgram in the presen ce of S9 mix.