Yoon Jihyun, Lim Dajung, Lee Seungwon, Kim Jiyu, Kim Inseon
Department of Agricultural Chemistry, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea.
Foods. 2022 Nov 4;11(21):3510. doi: 10.3390/foods11213510.
Pesticide residue is an increasing concern in rotational crop practices. The pesticide used for the primary crop may re-enter the secondary crop, thus exceeding pesticide levels set by the positive list system (PLS). As such, evaluation of pesticide residue translocated into rotational crops is required for ensuring pesticide safety. In this study, we investigated the residue pattern of diazinon translocated into lettuce as a typical rotational crop in Korea. Diazinon was used to treat greenhouse soil at the maximum annual application rate before crop planting. Diazinon residues in soil and lettuce were investigated using liquid chromatography/tandem mass spectroscopy and a modified quick, easy, cheap, effective, rugged, safe (QuEChERS) method. The limit of quantitation (LOQ) of diazinon was found as 0.005 mg/kg for the plant and soil samples. The recovery of diazinon at the LOQ and 10× the LOQ ranged from 100.2% to 108.7%. The matrix calibration curve showed linearity, with R2 values > 0.998. Diazinon residue in soil dissipated over time after the initial treatment, generating first-order kinetics (R2 = 0.9534) and having a half-life of about 22 days. The uptake ratio (UTR) of diazinon from the soil to the plant ranged from 0.002 to 0.026 over the harvest period. Considering the UTRs, diazinon residue in the edible leaf could exceed the PLS level (0.01 mg/kg) if lettuce is rotated in soil containing >0.357 mg/kg of diazinon. Based on our findings, to comply with the PLS, a 3-month plant-back interval is required following diazinon treatment and/or setting the maximum residue limit of diazinon for lettuce.
农药残留是轮作作物种植中日益受到关注的问题。用于主要作物的农药可能会重新进入次要作物，从而超过肯定列表制度（PLS）规定的农药限量。因此，为确保农药安全，需要对转移到轮作作物中的农药残留进行评估。在本研究中，我们调查了作为韩国典型轮作作物的生菜中乐果的残留模式。在作物种植前，以最大年施用量使用乐果处理温室土壤。采用液相色谱/串联质谱法和改良的快速、简便、廉价、高效、耐用、安全（QuEChERS）方法，对土壤和生菜中的乐果残留进行了研究。发现乐果在植物和土壤样品中的定量限（LOQ）为0.005 mg/kg。乐果在定量限和10倍定量限水平下的回收率在100.2%至108.7%之间。基质校准曲线呈线性，R2值>0.998。初始处理后，土壤中的乐果残留随时间消散，呈现一级动力学（R2 = 0.9534），半衰期约为22天。在收获期，乐果从土壤到植物的吸收比率（UTR）在0.002至0.026之间。考虑到UTR，如果在含有>0.357 mg/kg乐果的土壤中种植生菜，可食用叶片中的乐果残留可能会超过PLS限量（0.01 mg/kg）。根据我们的研究结果，为符合PLS，在乐果处理后需要3个月的种植间隔期和/或设定生菜中乐果的最大残留限量。
