Agriculture and Agri-Food Canada, Research Centre, 107 Science Pl., Saskatoon, SK, Canada S7N 0X2.
J Environ Qual. 2009 Dec 30;39(1):365-74. doi: 10.2134/jeq2008.0497. Print 2010 Jan-Feb.
Sulfonylurea herbicides are widely applied on the Canadian prairies to control weeds in a variety of crops. Several sulfonylurea herbicides are mobile in soil, and there is concern about their possible movement to ground water. This study was performed to assess the susceptibility of three sulfonylurea herbicides commonly used in prairie crop production to leach under a worst-case scenario. Thifensulfuron-methyl, tribenuron-methyl, and rimsulfuron were applied to a 9-ha tile-drained field, and then approximately 300 mm of irrigation water were applied over a 2-wk period using a center pivot. The commencement of tile-drain flow corresponded to the rise of the water table above tile-drain depth, and peak flow rates corresponded to the greatest depths of ground water above the tile drains. The volume of irrigation water intercepted by the tile drains in each quadrant was determined by site hydrology and represented <10% of the irrigation water applied. Concentrations of thifensulfuron-methyl, tribenuron-methyl, and rimsulfuron in the tile-drain effluent ranged (analysis by liquid chromatography/tandem mass spectrometry) from 2.0 to 248 ng L(-1), not detected (nd) to 55 ng L(-1), and nd to 497 ng L(-1), respectively. Total herbicide transport from the root zone in each quadrant was estimated at <0.5% of the amount of each sulfonylurea herbicide applied. Thifensulfuron-methyl was the only herbicide detected in ground water, with concentrations ranging from 1.2 to 2.5 ng L(-1). With the frequency and amount of rainfall typically encountered in the prairie region of Canada, detectable concentrations (>1 ng L(-1)) of these sulfonylurea herbicides in ground water would be unlikely.
磺酰脲类除草剂被广泛应用于加拿大草原，以控制各种作物中的杂草。几种磺酰脲类除草剂在土壤中具有移动性，因此人们担心它们可能会迁移到地下水。本研究旨在评估三种常用于草原作物生产的磺酰脲类除草剂在最坏情况下的淋溶敏感性。噻吩磺隆甲酯、三氟啶磺隆和啶嘧磺隆被施用于一个 9 公顷的有沟排水田，然后在 2 周内使用中心枢轴系统灌溉约 300 毫米的水。沟排水开始流动时，地下水位上升到沟排水深度以上，而峰值流速对应于地下水位高于沟排水的最大深度。每个象限的沟排水截留的灌溉水量由现场水文学确定，代表应用灌溉水的<10%。沟排水出口处噻吩磺隆甲酯、三氟啶磺隆和啶嘧磺隆的浓度（通过液相色谱/串联质谱法分析）范围为 2.0 至 248ng/L、未检出（nd）至 55ng/L 和 nd 至 497ng/L。每个象限中从根区到地下水中的总除草剂迁移量估计<每种磺酰脲类除草剂施用量的 0.5%。噻吩磺隆甲酯是唯一在地下水中检测到的除草剂，浓度范围为 1.2 至 2.5ng/L。在加拿大草原地区通常遇到的降雨频率和降雨量下，这些磺酰脲类除草剂在地下水中的检出浓度（>1ng/L）不太可能。
