Study On Fate Of Methoxyfenozide In Aquatic Microcosm

Microcosm as a kind of artificial control simulation ecosystem,it has been widely used as a research method for the ecological risk assessment of pesticides.Fugacity models have been gradually used to describe the environmental behavior and the fate of pesticides.The present study was combines two approaches:simulating aquatic microcosm experiments and multimedia fugacity model aim to study the transport and fate of methoxyfenozide in a microcosm(containing water,sediment,aquatic plant andzebra fish).The study can provide theoretical support for safety assessment of methoxyfenozide,and provide new idea for studying the environmental behavior and fate of other pesticide.The main results are listed as following:A new analytical method using optimized QuEChERS procedure for determination of methoxyfenozide in water,sediment,aquatic plant and zebra fish samples was developed using ultra-high performance liquid chromatography coupled with tandem mass spectrometry.The samples were extracted with acetonitrile(containing 2%(v/v)acetic acid)and cleanup by C18,GCB and Florisil.The established method exhibited good linearity with R~2>0.99,and the recoveries ranged from 73.99%to 114.72%with relative standard deviations ranged from 1.72%to 10.03%.The limits of quantification were 0.005mg/kg.At the end of the study(i.e.740h after the dose administration),results of the aquatic microcosm experiments with the sediment phase from Jilin showed that concentrations of methoxyfenozide in water,sediment,aquatic plant and zebra fish were 0.306 mg/L?1.25mg/kg?1.51mg/kg and 0.41mg/kg;results of the aquatic microcosm experiments with the sediment phase from Jiangsu showed that concentrations of methoxyfenozide in water,sediment,aquatic plant and zebra fish were 0.30 mg/L?0.68mg/kg?1.49mg/kg and0.56mg/kg;results of the aquatic microcosm experiments with the sediment phase from Hunan showed that concentrations of methoxyfenozide in water,sediment,aquatic plant and zebra fish were 0.34 mg/L?0.46mg/kg?2.49mg/kg and 0.51mg/kg.The average enrichment coefficients(BCF)of methoxyfenozide were1.65L/kg for zebra fish and5.57L/kg for aquatic plant.Predicted concentrations of methoxyfenozide in water and water grass were in good agreement with the observed ones.The predicted concentrations in sediment and zebra fish were generally lower than 1.0 logarithmic unites.There is an obvious mass transfer between each phase of methoxyhydrazide,the rates of transport was 0.279mg/h from water to sediment in Jiangsu microcosm.When systems under steady-state,methoxyhydrazide mass percentage in three types of aquatic microcosm were:accounted for 76.76%in water,accounted for 22.07%in sediment,accounted for 0.66%in aquatic plant and accounted for0.55%in zebra fish in Jilin microcosm;accounted for 80.42%in water,accounted for18.58%in sediment,accounted for 0.48%in aquatic plant and accounted for 0.52%in zebra fish in Jiangsu microcosm;accounted for 76.80%in water,accounted for 22.15%in sediment,accounted for 0.49%in aquatic plant and accounted for 0.56%in zebra fish in Hunan microcosm.