Synthetic pyrethroids, chlorpyrifos, and neonicotinoids are representatives of non-persistent insecticides ubiquitously used against insects all over the world. Their widespread use causes prevalent exposure to these compounds, which may be hazardous to human health. The insecticides have short biological half-lives and are mostly excreted in urine within 24 h after entering the human body; thus, the urinary concentration of their metabolites is highly dependent on the time elapsed between exposure and sample collection. Considering the within-day fluctuations in urinary concentration, one randomly collected sample may cause misclassification of long-term exposure. We evaluated the variability of excretion of eight insecticide metabolites in 24-h urine samples collected from 14 volunteers once or twice per month over 12 consecutive months. High detection frequency above 70% for non-specific metabolites of pyrethroid, chlorpyrifos, and neonicotinoids confirmed widespread exposure to these insecticides in the studied population. A long-term variability of exposure was assessed based on intraclass correlation coefficient (ICC). We found relatively low variability of excretion for non-specific pyrethroid metabolites and 3,5,6-trichloro-2-pyridinol (ICC > 0.75), but poor repeatability for 6-chloronicotinic acid. Constantly higher ICCs were observed for daily excretion than for unadjusted concentrations. Seasonal differences were observed for 3,5,6-trichloro-2-pyridinol and 6-chloronicotinic acid, with the highest and the lowest median concentration, respectively, in the summer. Due to high ICC values and lack of seasonal variations, one 24-h urine sample was considered sufficient to characterize long-term excretion of non-specific pyrethroid metabolites in non-occupationally exposed population. In addition, we calculated the daily intake (DI) for cypermethrin, permethrin, deltamethrin, and chlorpyrifos. The estimated DI values were mostly below the acceptable daily intake, which indicates that the evaluated exposure is non-hazardous to the population.

合成拟除虫菊酯，毒死rif和新烟碱类化合物是在世界各地普遍用于防治昆虫的非持久性杀虫剂的代表。它们的广泛使用导致这些化合物的大量暴露，这可能对人体健康有害。这些杀虫剂的生物半衰期很短，大部分在进入人体后24小时内排泄到尿液中。因此，其代谢产物的尿浓度高度依赖于暴露和样品收集之间的时间。考虑到尿液浓度在一天之内的波动，一个随机收集的样本可能会导致长期暴露的分类错误。我们评估了连续12个月每月一次或两次从14名志愿者收集的24小时尿液样本中8种杀虫剂代谢产物的排泄变异性。拟除虫菊酯，毒死rif和新烟碱类非特异性代谢物的高检出频率高于70％，这证实了研究人群中广泛暴露于这些杀虫剂。根据组内相关系数（ICC）评估暴露的长期变异性。我们发现非特异性拟除虫菊酯代谢物和3,5,6-三氯-2-吡啶醇（ICC> 0.75）的排泄变异性相对较低，但6-氯烟酸的重复性较差。每天排泄的ICC均比未调整的浓度高。夏季观察到3,5,6-三氯-2-吡啶醇和6-氯烟酸的季节差异，其中位数浓度分别最高和最低。由于ICC值较高且缺乏季节性变化，一个24小时尿液样本被认为足以表征非职业暴露人群中非特异性拟除虫菊酯代谢物的长期排泄。此外，我们计算了氯氰菊酯，氯菊酯，溴氰菊酯和毒死rif的每日摄入量（DI）。估计的DI值大多低于可接受的每日摄入量，这表明所评估的接触对人群无害。