| ZJ1835 is a new synthesis of pyrimidine salicylic herbicides,It has the advantages of good control effect and long holding time for the cotton field,goosegrass,retroflexus,purslane and other weeds before bud crabgrass.At the same time,The great majority of weeds in field were sensitive to ZJ1835,and the spectrum of weed control of ZJ1835 was wide.Therefore,it has a good application prospect.In this paper,a method for the residue determination of ZJ1835 was developed and the environmental behavior including soil absorption and desorption,soil leaching and soil degradation of ZJ1835 was investigated,aimed to know the environmental fate and thepotential hazards of ZJ1835,and provida scientificbasis for its rational use.The study focus on following four parts:1.A method was established for the determination of ZJ1835 residues in soil.Residues were extracted with acetonitrile,and determined with HPLC equipped by DAD detector.The results showed that the good linear relationship for ZJ1835 was obtained between 0.1 and 10.0 mg/L.The minimum detectable concentrations in soil was 0.002 mg/kg,and the minimum detectable amount of ZJ1835 standard was 1.0×10-12 g.respectively.The average of recoveries and coeficient of variations of ZJ1835 of the method were 96.7%-99.5%,2.4%-4.6% for soil samples,The results show that the method meet the demands of pesticide residue analysis.2.The adsorption-desorption experiments of ZJ1835 in soils were conducted by the batch equilibration techniques,furthermore,data were analyzed with mathematic models to describe the characteristic sand mechanism of adsorption-desorption and the shift of ZJ1835 in soils.The results showed that the adsorption-desorption isotherms of ZJ1835 was well described by Freundlich model,and the physical effect played the main role in adsorption-desorption process.The adsorption values Kf of ZJ1835 in 5 types of soils ranged from 6.991-18.494.It was found that the Kf values increased with increasing of organic matter(OM)and clay content,while,decreased with increasing of the soils pH values.The simple linear correlations were regressed between OM,clay contents or soils pH values and the values of adsorption coefficient(Kf),indicated that OM,clay contents and the soils pH were the dominating factors influencing the ZJ1835 retention in all of the systems.The mobility of ZJ1835 in 5 types of tested soils was low,so there was no risk to surface water and underground water during routine use.3.The leaching ability of ZJ1835 in five soils were studied by TLC and column leaching.Results showed that ZI1835 in the tested five kinds of soils display non-mobile and non-leaching,which indicted that under normal use,ZJ1835 was not easy to cause pollution of groundwater.The leaching capacities of ZJ1835 in five soils showed the following sequence: Black soil>Paddy soil>Cinnamon soil>Fluvo-aquic soil>Red soil.the leaching capacities weakened with the increasing of soil organic matter content.4.The degradation and mobility of ZJ1835 in five kinds of soils were investigated,and the influence factors of ZJ1835 degradation in soil were studied by using indoor simulating test.The result of soil degradation test showed that the half-lives of ZJ1835 in five sterilized soils were 23.90 d,24.76 d,31.51 d,38.51 d and 46.21 d,respectively,and in those five flooded soils,the half-lives were 11.95 d,14.75 d,16.91 d,19.80 d and 20.39 d,respectively,while in those soils,they were 17.77 d,21.66 d,22.36 d,27.73 d and 28.88 d.According to the pesticide degradation in soil classification standard,ZJ1835 in the five kinds of soil were easily degraded.the degradation rate in five soils showed the following sequence: Black soil>Paddy soil>Cinnamon soil>Fluvo-aquic soil>Red soil.The degradation rate was positively correlated with the organic matter(OM)of soils.All in aerobic,anaerobic and sterilized conditions,the degradation rate in five soils showed the following sequence: anaerobic > aerobic > sterilized.Therefore,ZJ1835 was degraded mainly by biodegradation in soils,and anaerobic microorganisms in anaerobic condition were conducive to the degradation. |
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