丙炔噁草酮在水环境中的降解行为研究

Degradation Behavior of Oxadiargyl in Water

进行了室外大田残留试验,监测了稻田水体中丙炔噁草酮的消解动态,结果表明,丙炔噁草酮在稻田水中的消解半衰期为1.2d。通过室内水解试验及模拟自然光降解试验,研究了丙炔噁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pH5.0和7.1的缓冲液中,丙炔噁草酮的降解半衰期均大于90d,而在pH9.6的缓冲溶液中的半衰期为3.7d。在室内25℃及在4 000±500lx氙灯光照下,其在田水和pH7.1、9.6的缓冲溶液中的降解半衰期分别为11.8、13.2和9.8h。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。

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.