title: Identification of a new mutagen, 4,4'-diamino-3,3'-dichloro-5-nitrobiphenyl, in river water flowing through an industrial area in Wakayama, Japan.
abstract: 3,3'-Dichlorobenzidine (DCB), which has been assigned as a possible carcinogen to humans (Group 2B) by IARC, is produced as a raw material in the manufacture of polymers and dye intermediates. In our previous paper, we identified DCB as an indirect-acting mutagenic constituent in the water concentrates from the Waka River, which flows through an industrial area in Wakayama, Japan. In this study, we have identified a novel mutagen in the water samples from the Waka River. Organic chemicals in the river water were adsorbed to blue rayon at the site where effluents from chemical plants and a sewage plant were discharged into the river. The adsorbate was highly mutagenic in Salmonella YG1024 in the presence and absence of S9 mix, inducing 440,000 and 170,000 revertants/g blue rayon equivalent, respectively. Two mutagenic fractions, which accounted for 18% and 12% of the total mutagenicity of the water concentrate in YG1024 with S9 mix, were separated by HPLC with a reversed-phase column following Sephadex LH20 column chromatography. Both fractions were further separated by HPLC using reversed-phase columns. On the basis of spectral analysis and co-chromatography using an authentic chemical standard, one mutagen in the former fraction was identified as DCB and one mutagen in the latter fraction was deduced to be a novel chemical, a 5-nitro derivative of DCB (5-nitro-DCB; 4,4'-diamino-3,3'-dichloro-5-nitrobiphenyl). 5-Nitro-DCB showed strong mutagenicity in YG1024 especially with S9 mix, inducing 24,200 revertants/microg. 5-Nitro-DCB was detected in water concentrates in the range from less than detection limit to 6.9 microg/g of blue rayon. DCB was also detected in the range from 13.2 to 104 micro/g of blue rayon. These results demonstrate that Waka River water might be continually contaminated with the indirect-acting mutagens DCB and 5-nitro-DCB as major mutagenic constituents of the river water.
authors.affiliation: Department of Food and Nutrition, Faculty of Home Economics, Kyoto Women's University, Kyoto 605-8501, Japan. ooe@kyoto-wu.ac.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ohe
authors.forename: Tetsushi
authors.initials: T
authors.lastname: Watanabe
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nonouchi
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Hasei
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Agou
authors.forename: Mayumi
authors.initials: M
authors.lastname: Tani
authors.forename: Keiji
authors.initials: K
authors.lastname: Wakabayashi
mesh_terms: D015101:3,3'-Dichlorobenzidine / Q000031:analogs & derivatives*; D000814:Aniline Compounds / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D001713:Biphenyl Compounds / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D002851:Chromatography, High Pressure Liquid; D007564:Japan; D008958:Models, Molecular; D009153:Mutagens / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity*; D045483:Rivers / Q000737:chemistry*; D012486:Salmonella typhimurium / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity*
chemical_list: C533958:4,4'-diamino-3,3'-dichloro-5-nitrobiphenyl; D000814:Aniline Compounds; D001713:Biphenyl Compounds; D009153:Mutagens; D014874:Water Pollutants, Chemical; D015101:3,3'-Dichlorobenzidine