氨唑草酮的水解、挥发及其在水-沉积物系统中的降解特性

为评价氨唑草酮的环境安全性,参照国家标准GB/T 31270-2014的要求,采用室内模拟法研究了氨唑草酮在不同温度和不同pH值缓冲溶液中的水解特性、在不同环境介质中的挥发特性,以及在2种水-沉积物系统中的降解特性。结果表明:氨唑草酮在25 ℃时,在pH值为4或7的缓冲液中水解半衰期均长于365 d,在pH值为9的缓冲液中水解半衰期为90.0 d,属于难水解至中等水解农药。在20~25 ℃、气体流速500 mL·min^-1的条件下,氨唑草酮在空气、水和土壤中的挥发率均小于1%,属于难挥发农药。氨唑草酮在湖泊(杭州西湖)水-沉积物系统和河流(京杭大运河)水-沉积物系统中的降解符合一级动力学方程,好氧降解半衰期分别为408 d和630 d,厌氧降解半衰期分别为248 d和990 d,在水-沉积物系统中属于难降解农药。

Hydrolysis,volatility and degradation of amicarbazone in water-sediment system

In order to evaluate the risk of amicarbazone in the environment, the hydrolysis, volatility and degradation characteristics of amicarbazone in water, soil and water-sediment system were investigated by laboratory tests according to the national standard GB/T 31270-2014. At 25 ℃, the half-life periods of hydrolysis were>365 d,>365 d and 90 d in buffer solutions with pH of 4, 7, and 9, respectively. The volatility rate of amicarbazone in air, water and soil was less than 1% under the conditions of 20-25 ℃ and 500 mL·min^-1 gas flow rate, which suggested amicarbazone was difficult to volatilize. The degradation of amicarbazone in lake (West Lake) and river (Grand Channel) water-sediment system accorded with the first-order kinetic equation. The degradation half-life period of amicarbazone in lake and rive water-sediment system was 408 d and 630 d, respectively, in aerobic conditions, and was 248 d and 990 d, respectively, in anaerobic conditions. These results indicated that amicarbazone was hard to degrade in water-sediment system.