Abstract: Photolystic kinetics of vinclozolin in various aqueous solutions under a high pressure mercury lamp and the sunlight were studied.The half-life of vinclozolin photolysis in redistilled water was 28 min and 3.86 h under a high pressure mercury lamp and the sunlight,respectively.Soluble substances in tap water and lake water showed faint influence on photodegradation of vinclozolin under the high pressure mercury lamp,but significant sensitizing effect under the sunlight,bringing the photosensitizing rate up to 138% and 126% in 3 h,respectively.Under either light sources,both buffers,pH 5.0 and pH 7.0,showed an obvious photoquenching effect on vinclozolin,but buffer pH 9.0 showed a strong photosensitizing effect,especially under the sunlight.The photoquenching rates of the buffers,pH 5.0 and pH 7.0,against vinclozolin were 69% and 57% under the high pressure mercury lamp for 60 min,respectively and 77% and 33% under the sunlight for 7 h,respectively.The photosensitizing rate of buffer pH 9.0 was 58% and 415% under the high pressure mercury lamp for 20 min and under the sunlight for 1 h,respectively. 

Key words: vinclozolin, photolysis, pH, photosensitizing effect, photoquenching effect, anti-androgen