| Bispyribac-sodium is a selective, systemic post-emergence herbicide. Its chemical abstracts name is sodium 2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxy] benzoate. Bispyribac-sodium has been used widely in world. Previous studies focused mainly on herbicidal efficacy and mechanism of bispyribac-sodium, little information was available about on its degradation principle in the environment, especially in water. In order to extend its use and provide some fundamental data for assessing the bio-environment safety and scientific application of bispyribac-sodium, the degradation behavior and the influencing factors of bispyribac-sodium in different environmental waters, and hydrolysis kinetics in Aqueous solutions were studied in this paper.The main results were summarized as following:Hydrolysis impact on temperature and pH was studied first. The results showed that the pH and temperature were critical factors determining the degradation rate of bispyribac-sodium in aqueous solutions. The hydrolysis of bispyribac-sodium was easily took place in acid water. And the pH was lower the degradation rate was quicker. But bispyribac-sodium was stable in basic and neutral water. In addition, the higher temperature accelerated the hydrolysis rate in acid water. When the pH value was 4, the temperature coefficient was 2.1.The activation energy (Ea) and the activation enthalpy (AH) had no visible relation with the temperature, but the entropy (AS) increased with the increasing temperature, and the mean activation entropy was -98.98 kJ/mol. In addition, the hydrolysis rate of different initial concentration of bispyribac-sodium was in order of 20 mg/L> 10 mg/L>5 mg/L. The hydrolysis rate of bispyribac-sodium increased with initial concentration of bispyribac-sodium enhanced.Influences of Humus, inorganic salts, DO and nitrogenous fertilizers on hydrolysis of bispyribac-sodium were studied. The hydrolysis of bispyribac-sodium were obtained at 298K and the pH 3.The result showed that Humus could promote the...
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