Canadian Forest Service, Natural Resources Canada, Fredericton, Canada.
Government of New Brunswick, Natural Resources & Energy Development, Forest Operations and Development Branch, Fredericton, Canada.
Pest Manag Sci. 2023 Aug;79(8):2951-2958. doi: 10.1002/ps.7473. Epub 2023 Apr 11.
Glyphosate is the most commonly used herbicide in the world, and is used in agriculture, forestry, and urban settings. In regions with high glyphosate use, such as agricultural, glyphosate and its' major derivative aminomethylphosphonic acid (AMPA) are frequently detected in surface waters. In Canadian forestry glyphosate-based herbicides are used to control vegetation that competes with conifer trees and are applied one to two times during a rotation, leading to infrequent application to the same area. Forestry occurs over a large spatial extent, and the cumulative application in space can lead to a large percentage of the land base receiving an application through time. To assess the frequency and concentration of glyphosate and AMPA in surface waters of a region where forestry is the dominant use sector, we conducted three monitoring programs targeting: (i) immediately after application, (ii) after rainfall, and (iii) cumulative application over a large spatial extent.
Across all monitoring programs we collected 296 water samples between August and October from eight river systems over two years and detected glyphosate in one sample at 17 ppb.
Glyphosate is not likely present in surface waters during baseflow conditions as a result of applications in forestry. Lack of detection is likely because soil capacity to bind glyphosate remains high due to infrequent applications to the same area, and factors that limit sediment transport to surface waters such as buffers. Additional sampling is needed during other stream conditions, ideally spring freshet, to determine peak concentrations. © 2023 National Research Council Canada. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. Reproduced with the permission of the Minister of Innovation, Science, and Economic Development.
草甘膦是世界上使用最广泛的除草剂，用于农业、林业和城市环境。在草甘膦使用量较高的地区，如农业区，地表水中经常检测到草甘膦及其主要衍生物氨甲基膦酸（AMPA）。在加拿大林业中，草甘膦基除草剂用于控制与针叶树竞争的植被，并在轮作期间使用一到两次，导致同一区域的应用频率较低。林业分布范围很广，随着时间的推移，在空间上的累积应用可能导致很大比例的土地接受应用。为了评估林业为主导使用部门的地区地表水中草甘膦和 AMPA 的频率和浓度，我们进行了三项监测计划，针对：（i）施药后立即，（ii）降雨后，和（iii）在大空间范围内的累积应用。
在两年的时间里，我们在 8 个河流系统中从 8 月到 10 月进行了所有监测计划，共收集了 296 个水样，在一个样本中检测到 17 ppb 的草甘膦。
由于林业中的应用，草甘膦在基流条件下不太可能存在于地表水中。未检测到可能是由于土壤对草甘膦的结合能力仍然很高，因为同一区域的应用频率较低，以及限制泥沙向地表水中迁移的因素，如缓冲区。需要在其他溪流条件下进行更多的采样，理想情况下是春季融雪期，以确定峰值浓度。©2023 加拿大国家研究委员会。Pest Management Science 由 John Wiley & Sons Ltd 代表化学工业协会出版。经创新、科学和经济发展部部长许可转载。
