Dissipation Residue And Environmental Risk Evaluation Of Pymetrozine In Paddy Field

This paper systematically studied the pyrazole ketone of aphid after fertilization in paddy fields by Pymetrozine, after choosing the zebrafish, large m., claw crescent algal receptors for ecological toxicology of water environment risk assessment, then evaluating the risk of the aquatic ecological toxicology through acute toxicity index. The main results were as follows:Determine the high performance liquid chromatography with uv detector analysis pyrazole ketone of aphid testing conditions, the minimum detection instrument quantity of 1.0 ×10-10 g, Pymetrozine were respectively 0.01,0.03,0.1,0.03 mg/kg at the lowest detection concentration in rice field water, soil, rice plants and rice;Using ammonia, acetonitrile and acetone solvent extraction, C-18 purification method of solid phase extraction small column on paddy rice paddy soil, water, rice, rice samples of pyrazole ketone of aphid before processing, pyrazole ketone of aphid in the matrix of adding recovery level changes within the range 77.07%-86.77%, relative standard deviation between 3.31%～3.31%.The residual dynamic test showed that 25% of pyrazole ketone of aphid WP in rice field water dissolve quickly, residues in the soil of half-life of 10.4 to 10.4 d,5.7 7.0 d, in the paddy rice plant residues in half-life of 7.3-7.3 d, degradation of pesticide more easily in 2013-2014.Final residual test results show that 25% of pyrazole ketone of aphid WP 75 and 150 g/ha (ai) applying 2 times or 3 times, recovery intervals for 3 days rice residue is close to or more than the limit, in 7 days and 14 days are less than the minimum detection limit, in order to ensure the safety of eating the recommended dose (ai) not more than 75 g/ha, times is no more than 2 times, applying pesticide spray interval,7 days harvest interval is more than 7 days in 2013-2014.25% pyrazole ketone of aphid wettable powder of zebrafish 96 h LC50 for 77 a.i.mg/L, according to the evaluation standard of chemical pesticide toxicity to fish,25% pyrazole ketone of aphid wettable powder on the acute toxicity of zebrafish as low toxicity.25% pyrazole ketone of aphid wettable powder of large m.48 h-EC50 33.8 a.i.mg/L, m. class according to the chemical pesticide toxicity evaluation standard,25% pyrazole ketone of aphid wettable powder in m. toxicity is low toxicity.25% pyrazole ketone of aphid wettable powder of algae 72 h-EC50> 30 a. i.mg/L, according to the evaluation standard of chemical pesticide toxicity to algae,25% pyrazole ketone of aphid wettable powder for low toxicity to algae.