新型灭螺药氯代水杨胺环境行为研究Ⅲ --水-沉积物系统降解特性

Environmental behavior study of the New Molluscicide LDS Ⅲ-Degradation in Water-sediment

目的测定与评价新型灭螺药氯代水杨胺(LDS)在水-沉积物中的降解特性,为该药登记提供环境影响资料。方法依据中华人民共和国国家标准《化学农药环境安全评价试验准则》第八部分:水-沉积物系统降解试验。结果好氧条件下,寡营养和富营养水-沉积物体系中氯代水杨胺总量的降解速率分别为0.026d-1、0.034d-1,降解半衰期分别为26.7和20.4d;厌氧条件下,寡营养和富营养水-沉积物体系中氯代水杨胺总量的降解速率分别为0.023d-1、0.025d-1,降解半衰期分别为30.1和27.7d。结论氯代水杨胺在好氧条件下的降解速率快于厌氧条件,富营养体系中的降解速率快于寡营养体系。氯代水杨胺在上述两种水-沉积物体系中的降解均较快。水-沉积物体系中的药物降解速率在21d前主要受水相中药物降解速率影响,而在21d后水相和沉积物相共同起作用。

Objective To measure and evaluate the degradation characters of a new molluseicide LDS in two types of watersediment. The reports would be provided for drug registration. Methods According to the National Standards of the People＇s Republic of China, Part 8：the chemical pesticide environmental safety evaluation test guidelines-transformation in water-sediment. Results In water-sediment system the degradation rates of LDS were 0. 026 d-1（ Oligotrophie system）, 0. 034d-1 （Eutrophy system）, the half-times were 26. 7d （ Oligotrophie system）, 20. 4d （ Eutrophy system） under aerobic conditions ions; while the degradation rates under anaerobic conditions were 0. 023 d-1 （ Oligotrophie system）, 0. 025d-1 （ Eutrophy system）, and the half-times were 30. ld （ Oligotrophie system）, 27. 7d （ Eutrophy system）. Conclusion The degradation rate of LDS was faster in aerobic conditions than in anaerobic conditions, and was faster in Eutrophy system than in Oligotrophie system. LDS degraded quickly in both two water-sediment systems. The rate of drug degradation in the water-sediment system was mainly affected by the rate of drug degradation in the aqueous phase before 21D, while the aqueous phase and sediment phase acted together after 21D.