中国农业科学 ›› 2020, Vol. 53 ›› Issue (17): 3587-3596.doi: 10.3864/j.issn.0578-1752.2020.17.015

• 食品科学与工程 • 上一篇    下一篇

氯噻啉在青菜上的残留特性及其膳食摄入风险评估

李晓贝(),赵晓燕(),李健英,陈磊,周昌艳,何香伟   

  1. 上海市农业科学院农产品质量标准与检测技术研究所,上海201403
  • 收稿日期:2019-12-17 接受日期:2020-03-11 出版日期:2020-09-01 发布日期:2020-09-11
  • 通讯作者: 赵晓燕
  • 作者简介:李晓贝,Tel:021-67131635;E-mail:lixiaobei212@sina.com
  • 基金资助:
    上海市农委科技兴农推广项目(沪农科推字2017第4-3号)

Residue Behavior and Dietary Intake Risk Assessment of Imidaclothiz in Pakchoi (Brassica chinensis L.)

LI XiaoBei(),ZHAO XiaoYan(),LI JianYing,CHEN Lei,ZHOU ChangYan,HE XiangWei   

  1. Institute for Agri-Food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, Shanghai 201403
  • Received:2019-12-17 Accepted:2020-03-11 Online:2020-09-01 Published:2020-09-11
  • Contact: XiaoYan ZHAO

摘要:

【目的】明确氯噻啉在青菜上的残留特性,为制定氯噻啉在青菜上的安全使用标准提供科学依据。【方法】于上海市松江区进行10%氯噻啉可湿性粉剂在冬季与夏季不同生长季节及露地与大棚不同种植环境下的青菜上的残留试验,其中残留消解动态试验以90 g(a.i.)·hm-2(最高推荐剂量的1.5倍)的剂量施用1次,施药后0(2 h)、1、2、3、4、5、7、10、14、21和30 d连续采集青菜样品检测氯噻啉残留量;最终残留试验以60 g(a.i.)·hm-2(最高推荐剂量)和高剂量90 g(a.i.)·hm-2(最高推荐剂量的1.5倍)两个施药浓度,间隔7 d,施药2—3次,分别于最后一次施药后3、5和7 d采集青菜样品检测氯噻啉残留量。利用QuEChERS前处理方法对青菜中的氯噻啉残留进行提取净化,通过超高效液相色谱–串联质谱法检测氯噻啉在青菜上的残留量。基于最终残留试验结果及青菜的膳食消费量,应用风险商对青菜中氯噻啉残留量进行风险描述,以氯噻啉每日允许摄入量为标准对不同人群的膳食摄入风险进行评估,涵盖未成年男女(3—6岁幼儿及7—19岁儿童青少年)和成年男女(20—59成年人及60—69岁老年人)8类人群。【结果】在0.01—1.0 mg·kg-1的添加浓度范围内,氯噻啉在青菜中的添加回收率为77.2%—87.9%,相对标准偏差为2.5%—3.0%,检出限为0.0002 mg·kg-1,定量限为0.01 mg·kg-1,可满足检测需求。残留试验结果显示:10%氯噻啉可湿性粉剂以90 g(a.i.)·hm-2的施药剂量在青菜上的降解趋势符合一级动力学方程,在冬季大棚、夏季大棚及夏季露地青菜上的消解动态方程分别为C=0.8476e-0.158t、C=1.6558e-0.212t、C=4.3069e-1.197t,半衰期分别为4.39、3.27和0.58 d,消解时间及种植条件均对氯噻啉在青菜上的消解效率有显著影响(P<0.05);以60 g(a.i.)·hm-2和90 g(a.i.)·hm-2的施药剂量在青菜上间隔7 d喷雾2—3次,最后一次施药7 d后冬季大棚内青菜上氯噻啉最终残留量低于0.5 mg·kg-1,最后一次施药3 d后夏季露地及大棚青菜上氯噻啉最终残留量均低于0.5 mg·kg-1,最终残留量与施药浓度基本成正相关,与施药次数无显著相关性(P>0.05)。膳食摄入风险评估结果显示:各类人群通过青菜摄入氯噻啉的风险商最大值为0.2196,远低于1。【结论】氯噻啉属易降解农药,夏季青菜中氯噻啉消解速率高于冬季,露地高于大棚。中国普通居民由青菜摄入氯噻啉的风险较低,慢性摄入风险均可接受。因此,在推荐使用浓度下(45—60 g(a.i.)·hm-2)间隔7 d施用,最多施用3次,安全间隔期夏季3 d、冬季7 d,氯噻啉可安全有效地用于青菜虫害防治。

关键词: 青菜, 氯噻啉, 残留, 大棚, 露地, 风险评估

Abstract:

【Objective】The objective of the experiment was to reveal the residue behavior of imidaclothiz in pakchoi (Brassica chinensis L.), so as to provide a scientific basis for its safety utilization.【Method】Field experiments of 10 % imidaclothiz wettable powder in pakchoi under open field and greenhouse conditions were carried out in winter (between November and December) of 2018 and summer (between July and August) of 2019 at Shanghai. In dissipation experiments, the dosage of imidaclothiz was 90 g (a.i.)·hm-2(1.5 times recommended dosage) with one-time spray, and the treated samples were collected randomly from several points of each plot at 2 h, 1, 2, 3, 4, 5, 7, 10, 14, 21, and 30 days after spraying of the pesticide to detect the residual concentration. For the study of final residue of imidaclothiz in pakchoi, imidaclothiz was sprayed for 2-3 times at an internal of 7 days at the recommended dosage (60 g (a.i.)·hm-2) and 1.5 times recommended dosage (90 g (a.i.)·hm-2), and the treated samples were collected randomly at 3, 5, and 7 days after the final processing to detect the residual concentration. The QuEChERS method coupled with ultra-high performance liquid chromatography-tandem mass spectrum (UPLC-MS/MS) was used to determine imidaclothiz in pakchoi. Dietary intake risk assessments were processed based on the maximal concentration, acceptable daily intake (ADI) of imidaclothiz, and daily consumption of pakchoi. The people involved in the experiment were divided into 8 classes, including underage male and female (subdivided into 3-6 years old infants and 7- 19 years old teenagers), as well as adult male and female (subdivided into 20-59 years old adults and 60-69 years old elder crowed).【Result】The limit of detection (LOD) of imidaclothiz was 0.0002 mg·kg-1, and the limit of quantitation (LOQ) was 0.01 mg·kg-1. Recoveries of imidaclothiz in pakchoi ranged from 77.2% to 87.9% at 0.01, 0.10 and 1.0 mg·kg-1spiked levels, respectively, and the relative standard deviations (RSDs) were in the range of 2.5%-3.0%. The developed analytical method was suitable for the determination of imidaclothiz in pakchoi. Field experiments showed that the dissipation dynamics of imidaclothiz sprayed at the dosage of 90 g (a.i.)·hm-2in pakchoi exhibited a first-order kinetic decline. The regression equation of imidaclothiz in winter greenhouse, summer greenhouse and summer open fields were C=0.8476e-0.158t, C=1.6558e-0.212t and C=4.3069e-1.197t, and their half-lives were 4.39, 3.27 and 0.58 days, respectively. Both existing time and plant conditions had significant correlation with degradation efficiency of imidaclothiz in pakchoi (P<0.05). The maximal concentrations of imidaclothiz in pakchoi under winter greenhouse were all below 0.5 mg·kg-1 at 7 days after the final processing, when it was sprayed for 2-3 times at an internal of 7 days at the dosage of 60 or 90 g (a.i.)·hm-2 in pakchoi, while it just required 3 days to decline below 0.5 mg·kg-1 for those treated in summer in the same place, regardless of greenhouse and open fields. The final residue concentrations had positive correlation with spraying dosage, but no relationship with spraying number (P>0.05). The risk assessments showed that hazard quotients (HQs) of imidaclothiz for different groups consuming pakchoi were far below 1, and the maximum HQ was 0.2196.【Conclusion】Imidaclothiz was a kind of easily degradable pesticide, and its degradation rate was significantly higher in summer than winter, as well as higher in open fields than greenhouse. The dietary exposure of imidaclothiz only by pakchoi’s consumption was at a relatively low level to the ordinary resident of China. Generally, it’s effective to use imidaclothiz as the pest control method for pakchoi, accompanied with recommended dosage (45-60 g (a.i.)·hm-2) and appropriate pre- harvest intervals (7 days in winter and 3 days in summer).

Key words: pakchoi, imidaclothiz, residue, greenhouse, open field, risk assessment