Wołejko Elżbieta, Kaczyński Piotr, Łozowicka Bożena, Wydro Urszula, Borusiewicz Andrzej, Hrynko Izabela, Konecki Rafał, Snarska Krystyna, Dec Dorota, Malinowski Paweł
Division of Sanitary Biology and Biotechnology, Białystok University of Technology, Wiejska 45 E, 15-351, Białystok, Poland.
Laboratory of Pesticide Residues, Plant Protection Institute - National Research Institute, Chelmońskiego 22, Białystok, Poland.
Environ Monit Assess. 2017 Jul;189(7):355. doi: 10.1007/s10661-017-6071-7. Epub 2017 Jun 27.
The present study aimed at evaluating the dissipation of S-metolachlor (S-MET) at three doses in maize growing on diverse physico-chemical properties of soil. The effect of herbicide on dehydrogenase (DHA) and acid phosphatase (ACP) activity was estimated. A modified QuEChERS method using LC-MS/MS has been developed. The limit of quantification (0.001 mg kg) and detection (0.0005 mg kg) were very low for soil and maize samples. The mean recoveries and RSDs for the six spiked levels (0.001-0.5 mg kg) were 91.3 and 5.8%. The biggest differences in concentration of S-MET in maize were observed between the 28th and 63rd days. The dissipation of S-MET in the alkaline soil was the slowest between the 2nd and 7th days, and in the acidic soil between the 5th and 11th days. DT of S-MET calculated according to the first-order kinetics model was 11.1-14.7 days (soil) and 9.6-13.9 days (maize). The enzymatic activity of soil was higher in the acidic environment. One observed the significant positive correlation of ACP with pH of soil and contents of potassium and magnesium and negative with contents of phosphorus and organic carbon. The results indicated that at harvest time, the residues of S-MET in maize were well below the safety limit for maize. The findings of this study will foster the research on main parameters influencing the dissipation in maize ecosystems.
本研究旨在评估三种剂量的S-异丙甲草胺（S-MET）在具有不同理化性质土壤中生长的玉米中的消解情况。评估了除草剂对脱氢酶（DHA）和酸性磷酸酶（ACP）活性的影响。开发了一种使用液相色谱-串联质谱的改良QuEChERS方法。土壤和玉米样品的定量限（0.001 mg/kg）和检测限（0.0005 mg/kg）非常低。六个加标水平（0.001 - 0.5 mg/kg）的平均回收率和相对标准偏差分别为91.3%和5.8%。在第28天和第63天之间观察到玉米中S-MET浓度的最大差异。S-MET在碱性土壤中的消解在第2天至第7天最慢，在酸性土壤中在第5天至第11天最慢。根据一级动力学模型计算的S-MET半衰期为11.1 - 14.7天（土壤）和9.6 - 13.9天（玉米）。酸性环境中土壤的酶活性较高。观察到ACP与土壤pH值以及钾和镁含量呈显著正相关，与磷和有机碳含量呈负相关。结果表明，在收获时，玉米中S-MET的残留量远低于玉米的安全限量。本研究结果将促进对影响玉米生态系统中消解的主要参数的研究。
