Abstract
Chromatophoroma in Nibea mitsukurii showed a unique geographic distribution in Japan. The epidemiological and laboratory studies demonstrated that the fish tumor was induced by several environmental mutagens/carcinogens which were discharged from industrial effluent. Especially, chlorinated acetones and dicarbonyl compounds were potential candidates as genotoxic compounds. After chlorine-disinfection of drinking raw water, many kinds of chlorinated organic compounds were formed. Among them, 3-chloro-4-dichloromethyl-5-hydroxy-2(5H)-furanone (MX) showed the highest mutagenic activity on S.typhimurium TA100 without metabolic activation. The distribution of MX in drinking water in Japan was determined. The precursor and DNA modification of MX were also studied. The mutagenic and carcinogenic potency of MX was observed by two-stage carcinogenicy test in rats. These experiments showed that environmental mutagens and carcinogens might be potential substances to induce certain tumors not only to aquatic animals but also human beings.
