Brain Richard A, Perine Jeff, Cooke Catriona, Ellis Clare Butler, Harrington Paul, Lane Andrew, O'Sullivan Christine, Ledson Mark
Syngenta Crop Protection, Greensboro, North Carolina, USA.
Smithers Viscient, Harrogate, North Yorkshire, United Kingdom.
Environ Toxicol Chem. 2017 Sep;36(9):2465-2475. doi: 10.1002/etc.3786. Epub 2017 Apr 4.
Nature of exposure is a fundamental driver in nontarget terrestrial plant risk assessment for pesticides; consequently a novel study was designed to generate field-based drift exposure and evaluate corresponding biological effects of the herbicide mesotrione. The approach used a combination of US guideline drift reduction technology and vegetative vigor approaches. In each of 3 independent replicate spray application trials, 10 pots each of lettuce and tomato were placed at distances of 10, 20, 30, 40, and 50 ft (∼3, 6, 9, 12, and 15 m) from the downwind edge of the spray boom. Each application was conducted using a commercial 60-ft (18-m) boom sprayer fitted with TeeJet Technologies TTI110025 nozzles, with a nominal application rate of 0.2 lb a.i./A (224 g a.i./ha). The environmental conditions required by the protocol (air temperature 10-30 °C and wind perpendicular to the swath (±30°) blowing toward the plants at a mean wind speed of ≥10 mph [≥4.5 m/s] measured at 2.0 m above the ground) were met for each application. Following exposure, plants were transferred to a greenhouse for the 21-d vegetative vigor phase of the study. Symptoms of phytotoxicity and plant height were assessed at 7, 14, and 21 d after treatment. On completion of the 21-d after treatment assessment, all plants were harvested and dried in an oven to determine shoot dry weight. The biological data indicated that no statistically significant effects were observed at a distance of 30 ft (∼9 m) from mesotrione drift at wind speeds of ≥10 mph (10.9-12.4 mph); this endpoint (30 ft) is defined as the no observed effects distance (NOED). Environ Toxicol Chem 2017;36:2465-2475. © 2017 SETAC.
暴露性质是农药非靶标陆生植物风险评估的一个基本驱动因素；因此，设计了一项新研究来产生基于田间的漂移暴露，并评估除草剂甲基磺草酮的相应生物学效应。该方法结合了美国指南中的漂移减少技术和营养活力方法。在3个独立重复的喷雾应用试验中，生菜和番茄各10盆分别放置在距喷杆下风边缘10、20、30、40和50英尺（约3、6、9、12和15米）处。每次应用使用配备TeeJet Technologies TTI110025喷嘴的商用60英尺（18米）喷杆喷雾器进行，标称施用量为0.2磅活性成分/英亩（224克活性成分/公顷）。每次应用均满足该方案要求的环境条件（气温10 - 30°C，风向垂直于喷幅（±30°）吹向植物，在距地面2.0米处测得的平均风速≥10英里/小时[≥4.5米/秒]）。暴露后，将植物转移到温室进行为期21天的营养活力阶段研究。在处理后7、14和21天评估植物毒性症状和株高。在处理后21天评估完成后，收获所有植物并在烘箱中干燥以测定地上部干重。生物学数据表明，在风速≥10英里/小时（10.9 - 12.4英里/小时）时，距甲基磺草酮漂移30英尺（约9米）处未观察到统计学上的显著影响；这个端点（30英尺）被定义为无观察效应距离（NOED）。《环境毒理学与化学》2017年；36:2465 - 2475。©2017年环境毒理学与化学学会。
