噻虫嗪及其光解产物对土壤微生物活性的影响  

Effects of Thiamethoxam and Its Photo-Degradation Products on Soil Microbe Activity

作　　者：刘国光[1] 姚琨[1] 郑立庆[1] 周庆祥[1] 张锋[1] 

机构地区：[1]河南师范大学化学与环境科学学院河南省环境污染控制重点实验室,河南新乡453007

出　　处：《农业环境科学学报》2005年第5期870-873,共4页Journal of Agro-Environment Science

基　　金：河南省创新人才工程资助项目(教育[2002]513号)

摘　　要：为评价新烟碱农药噻虫嗪对土壤环境的影响,通过密闭碱吸收测定法,研究了噻虫嗪在不同浓度下对土壤微生物呼吸作用的影响,噻虫嗪和氮肥共同作用下对土壤呼吸作用的影响以及噻虫嗪经过不同光照时间后降解产物对土壤呼吸作用的影响。结果表明,高浓度的噻虫嗪对土壤微生物有一定的抑制作用,低浓度的噻虫嗪抑制作用不明显,其光解的不同时间产物对土壤呼吸表现出一定的刺激作用,噻虫嗪本身对土壤微生物的抑制作用在土壤肥力较好时表现不明显。用3种评价方法进行评价,结果表明噻虫嗪属于低毒或无实际危害的农药。Thiamethoxam,4H-1,3,5-oxadiazin-4-imine,3-[（2-chloro-5-thiazoly）methyl]tetrahydro-5-methyl-N-nitro（CAS）, is a new neonicotinoid pesticide which acts agonistically on insect nicotinic acetycholine receptors, and now is widely used against a broad range of pests such as aphids, whiteflies, and planthoppers as well as some coleopteran and lepidopteran pest species. Under the laboratory conditions, the effects of thiamethoxam and its photo-degradations on soil microbe activity were systematically investigated. The results showed that more significantly negative effects were observed with higher concentration of thiamethoxam, which meant that the inhibitory effects were much more prominent at 50mg·kg^-1 than 5 mg·kg^-1 and 20mg·kg^-1. Moreover, the inhibitory effects of thiamethoxam on microbe activity in all soil samples disappeared after ten days. Compared with the CO2 release rate of soil added into 20mg·kg^-1 thiamethoxam, the CO2 release rate of the soil added into 20 mg·kg^-1 urea and 20mg·kg^-1 thiamethoxam was faster. In general, the higher the concentrations of thiamethoxam, the more negative effects on soil microbe. The photochemistry reaction plays an important role in the degradation of chemical pollutions in natural conditions, that is, the photodegradation may lead either more contaminated or less contaminated results in the environment. So the effects of the photoproducts of thiamethoxam on microbe activity should be highly concerned. From our results, the average photolytic half- time of the thiamethoxam with 500 W xenon lamp in aqueous solution was about 6.01 h, and the photoproducts seemed to have positive effects on microbe activity. As a whole, it can be certain that thiamethoxam belongs to low poisonous or no poisonous pesticide based on safety assessment standard.

关 键 词：噻虫嗪 微生物活性 土壤呼吸 

分 类 号：X172[环境科学与工程—环境科学]