Nontarget impacts of routine aerial silvicultural practices on surface water quality are not well documented. Thus, uncertainty remains regarding herbicide treatment effects on ecological and human health. To investigate factors that influence silvicultural herbicide concentrations in surface water and identify any potential risks, we conducted a 2‐year study that monitored multiple streams for herbicide residues following aerial application of glyphosate, clopyralid, sulfometuron methyl (SMM), and metsulfuron methyl (MSM). The monitored streams drain recently harvested forest lands that also serve as municipal water sources for nearby communities in western Oregon's north coast range. A paired watershed design targeted predicted episodic pulses with water samples collected before, during, and after herbicide application, and during the first posttreatment storm events. We report no relic herbicide detections in control or test streams. Aerial application of glyphosate, clopyralid, SMM, and MSM resulted in no detections in control streams and only trace, episodic concentrations in test streams. Across all test streams from both study years, maximum SMM and MSM detections (≤0.030 μg/L) consistently occurred during the first storm event at sampling locations closest to the treated harvest unit. Results indicate that proximity to the treatment site, time from application, and rainfall influence herbicide presence and concentrations in surface water. Furthermore, detections of trace SMM and MSM concentrations were more than 25 000‐fold and 60 000‐fold below federal human health safety benchmarks for chronic exposure, respectively. We provide empirical context for understanding surface water herbicide presence following aerial silviculture application under modern forestry best management practices and identify potential risk to ecological and human health. Integr Environ Assess Manag 2019;00:1–14. © 2019 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC)

中文翻译：

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在俄勒冈州北海岸范围造林空中施用后，非生物因素影响地表水除草剂浓度。


常规空中造林实践对地表水质量的非目标影响尚未得到充分记录。因此，除草剂处理对生态和人类健康的影响仍然存在不确定性。为了调查影响地表水中造林除草剂浓度的因素并识别任何潜在风险，我们进行了一项为期 2 年的研究，监测空中施用草甘膦、二氯吡啶酸、甲磺隆 (SMM) 和甲磺隆 (MSM) 后多条溪流的除草剂残留情况）。监测到的溪流排干了最近收获的林地，这些林地也是俄勒冈州西部北海岸范围附近社区的市政水源。配对分水岭设计的目标是预测偶发性脉冲，在除草剂施用之前、期间和之后以及第一次处理后风暴事件期间收集水样。我们报告在对照或测试流中没有检测到残留除草剂。空中施用草甘膦、二氯吡啶酸、SMM 和 MSM 导致在对照流中没有检测到，而在测试流中仅检测到痕量、间歇性浓度。在两个研究年的所有测试流中，最大 SMM 和 MSM 检测值 (≤0.030 μg/L) 始终出现在第一次风暴事件期间，在距离处理收获单元最近的采样位置。结果表明，距离处理地点的远近、施用时间和降雨量都会影响地表水中除草剂的存在和浓度。此外，检测到的痕量 SMM 和 MSM 浓度分别比长期接触的联邦人类健康安全基准低 25 000 倍和 60 000 倍以上。 我们为了解现代林业最佳管理实践下空中造林应用后地表水除草剂的存在提供了经验背景，并确定了对生态和人类健康的潜在风险。整体环境评估管理2019；00:1–14。 © 2019 作者。综合环境评估和管理由 Wiley periodicals, Inc. 出版。代表环境毒理学与化学学会 (SETAC)