棉花植株和棉田土壤中氟节胺消解动态分析及残留量膳食摄入评估

Dissipation Analysis of Flumetralin in Cotton Plants and Soil under Field Conditions and Risk Assessment for Dietary Residue Intake

为了对氟节胺在棉花生产上应用的安全性进行评价，通过建立氟节胺在棉子、棉叶和土壤中的前处理和检测方法，对其进行定量分析。通过2年2地的残留试验，研究棉子、棉叶和土壤中氟节胺的残留及消解动态．并对棉子中的残留量进行风险评估。结果表明，氟节胺在棉子、棉叶和土壤中对照添加平均回收率为73-25％～98．28％，相对标准偏差为1．68％～9．93％，在土壤、棉叶及棉子中的最低检测限（质量分数）分别为O．05、0．05和0．1mg·kg-1.该方法重现性好，准确度、精密度高，可满足氟节胺在棉花上的残留分析要求。氟节胺在棉叶和土壤中的消解半衰期分别为0．81～3．7d、5．4～8．7d；不同施药次数、施药剂量及采样间隔期．氟节胺在棉子及土壤中的最终残留量（质量分数）分别为≤O．54mg·kg-1和≤0．81mg·k-1氟节胺普通人群国家估计每日摄入量是5．19×10-5mg，占日允许摄入量的0．01％左右，按本试验方式进行施药，通常不会对一般人群健康产生不可接受的风险。一定的采收间隔期内，施药剂量对氟节胺在棉子中的最终残留量有影响。

In order to determine whether flumetralin usage was safe under the recommended dosage, we established an analytical method and investigated the dissipation dynamics and terminal residues of flumetralin in cotton crops and in soil under field con- ditions. The residue levels and dissipation rates of flumetralin in cotton and soil were determined by the gas chromatography us- ing an electron capture detector （GC-ECD）. At fortification levels of 0.05, 0.5 and 1 mg.kg-1 in cotton leaves and in soil and of 0.1, 0.5 and 1 mg.kg-1 in cotton seeds, recoveries were shown to range from 73.25 to 98.28 percent, with a relative standard de- viation （RSD） of 1.68 to 9.93 percent. The limits of quantification （LOQ） were 0.05, 0.05 and 0.1 mg.kg-1 for soil, cotton leaves and cotton seeds, respectively. The dissipation half-lives of flumetralin in cotton leaves and in soil were 0.81--3.7 days and 5.4-- 8.7 days, respectively. The terminal residues at harvest in cotton seeds and in soil were lower than 0.54 mg.kg-1 and 0.81 mg. kg-1, respectively. The potential health risk induced by flumetralin was not significant based on supervised residue trial data. When the intervals to harvest were 20 and 30 days, there was no effect of dosage or frequency on the terminal residues; when the interval to harvest was 10 days, the dosage and frequency may have had an effect on the terminal residues. Our recommenda- tions are that flumetralin （SC, 25%） be applied to wheat crops at a dosage of 450 g .hrn-2 using a pre-harvest interval （PHI） of at least 20 days between the last application and the harvest. These results would help the government to establish the maximum residue limit of flumetralin in cotton and to provide guidance concerning the proper and safe use of flumetralin.