丙炔 口 恶 草酮在水环境中的降解行为研究

进行了室外大田残留试验,监测了稻田水体中丙炔 口 恶 草酮的消解动态,结果表明,丙炔 口 恶 草酮在稻田水中的消解半衰期为1.2 d。通过室内水解试验及模拟自然光降解试验,研究了丙炔 口 恶 草 酮在稻田水与不同pH缓冲溶液中的水解及光降解规律。在室内25℃避光的田水与pH 5.0 和7.1的缓冲液中,丙炔 口 恶 草酮的降解半衰期均大于90 d,而在pH 9.6的缓冲溶液中的半衰期为3.7 d。在室内25℃及在 4 000±500 lx氙灯光照下,其在田水和pH 7.1、9.6的缓冲溶液中的降解半衰期分别为11.8、13.2和9.8 h。光对水解的显著影响可通过半衰期的长短变化来揭示,表明光照是该药剂在室外田水中迅速降解的一个重要环境因素。

Degradation Behavior of Oxadiargyl in Water

The dissipation of oxadiargyl,including hydrolysis and photolysis was investigated through field experiment and laboratory study.The half-life of oxadiargyl in paddy field was 1.2 d,whereas it changed to be over 90 days in paddy field water (dark and at 25℃).Degradation of oxadiargyl was supposed to be pH dependent.The half-lives were beyond 90 d at pH 5.0 or pH 7.1,whereas it decreased to 3.7 d at pH 9.6.It was found that when the media were treated with Xe-lamp with light intension from 3 500 to 4 500 lx,half-life of oxadiargyl varies from 11.8 h in paddy field water,13.2 h in buffer solution of pH 7.1,and 9.8 h in that of pH 9.6,respectively.In conclusion,the notable difference among the half-lives in terms of the hydrolysis and photolysis indicated that the sunlight was an important factor that induced the fast degradation of oxadiargyl in the field.