25%异丙威·毒死蜱乳油在稻米和土壤中的最终残留测定

Final Residue of 25% Isoprocarb and Chlorpyrifos EC in Rice and Soil

为全面准确地评价25％异丙威·毒死蜱乳油在水稻上使用后的生态环境安全性，指导其科学合理使用，借助GC—NPD检测技术，通过田间试验研究异丙威和毒死蜱在稻米和土壤中的最终残留。2010年和2011年在贵阳、长沙和天津3地进行的田间残留试验结果表明，在水稻生长期按推荐用药剂量和1．5倍推荐剂量喷施25％异丙威·毒死蜱乳油3～4次，末次用药33d后，异丙威在稻米中的残留量≤0．049mg／kg，低于我国规定的最大残留限量（MRL）0．20mg／kg，土壤中未检测到异丙威残留；毒死蜱在稻米中的残留量≤0．038mg／kg，土壤中的残留量≤0．054mg／kg，均低于我国规定的最大残留限量0．10mg／kg。建议采用25％异丙威·毒死蜱乳油防治水稻二化螟时，有效成分最高用量0．27g／m2，最多施药4次，安全间隔期为33d。

In order to assess the ecological environment safety of 25% isoprocarb and chlorpyrifos EC comprehensively after it was applied in paddy and to guide the use of 25% isoprocarb and chlorpyrifos EC scientifically and reasonably,this research conducted a field experiment to detect the pesticide residues of isoprocarb and chlorpyrifos in rice and soil, using the measurement technique of GC-NPD. The residues of 25% isoprocarb and chlorpyrifos EC in the trials in Guiyang, Changsha and Tianjin cities were investigated in the years of 2010 and 201l. The results showed that spraying 25% isoprocarb and chlorpyrifos EC for three to four times according to the conventional dosage and high dosage （ 1.5 times the conventional dosage） in the rice growing period, after 33 d, the residues of isoprocarb were HO. 049 mg/kg in rice and were not detected in the soil. They were both below the maximum residue limit of 0.20 mg/kg set in China. The residues of chlorpyrifos were H 0. 038 mg/kg in rice, and H 0. 054 mg/kg in soil. They were both below the maximum residue limit of 0.10 mg/kg. These suggest that 25% isoprocarb and chlorpyrifos EC could be used in rice filed safely when the dosage is below 0.27 g/m2 , and the spray frequency should not be more than four times ,with the preharvest interval（PHI）of 33 d.