Residue Determination and Degradation of Niclosamide Ethanolamine in Rice and Paddy System

To determine the safety of niclosamide ethanolamine in rice ecosystem, a field experiment was conducted to reveal residual dynamics and final residue of niclosamide ethanolamine in rice and paddy system in Changsha, Hangzhou and Guiyang of China. The degradation dynamics and the final residue results of niclosamide ethanolamine in rice and paddy system showed that the degradation half-lives in rice plant, paddy water and soil were 1.69～3.01 d, 8.66～13.86 d and 5.33～7.70 d respectively in three places. The final residue of niclosamide ethanolamine in unpolished rice was low than 1.00 mg·kg-1 at an interval of 62 d. However, The final residue of niclosamide ethanolamine in rice plant were higher than those in rice husk, unpolished rice and paddy soil. According to the results, when 70% wettable powder of niclosamide ethanolamine were sprayed in rice for twice according to the recommended dose of 900 g·hm-2(630 a.i.g·hm-2), the safe period of niclosamide ethanolamine in rice could be set as 62 d.