A time-of-travel synoptic survey was conducted in August 2014 to assess pesticide occurrence in major river subbasins of southern Alberta, Canada. We collected 155 water samples from Alberta's South Saskatchewan River Basin (Bow, Oldman, Red Deer, and South Saskatchewan river subbasins) and analysed them for 106 pesticides. Samples were collected from mainstems (rivers) as well as tributaries and effluents (point sources) discharging into the rivers in an estimated time-of-travel to capture agricultural and urban contributions as the water flowed eastward from headwaters in the Rocky Mountains. The aim of the study was to assess point-source contributions of pesticides to Alberta's South Saskatchewan River Basin mainstems during low flow conditions. In addition to examining differences in pesticide contributions among source type and subbasins, the cumulative effect of inputs on the mainstem rivers, the influence of land use, and seasonality of pesticides in select effluents was analysed. We detected 17 pesticides and 1 metabolite, reflecting runoff from agricultural and urban land use. Pesticide detection frequency was significantly higher in effluents than in tributaries and mainstems, and pesticides were detected in effluents in summer and winter. Our evaluation of land-use relationships highlighted the influence of agriculture on pesticide occurrence in these aquatic agroecosystems. To our knowledge, this is the first watershed-wide time-of-travel survey of pesticides conducted in southern Alberta to measure contributions of pesticide loads from effluents and tributaries to the mainstems in all regions of Alberta's South Saskatchewan River Basin.

2014年8月进行了一次行进天气概要调查，以评估加拿大艾伯塔省南部主要河流流域的农药发生情况。我们从艾伯塔省的萨斯喀彻温省南部流域（弓，奥德曼，马鹿，南萨斯喀彻温省流域）收集了155个水样，并对其中的106种农药进行了分析。从估计的行程时间内，从主干（河流）以及支流和流出物（点源）排放到河流中收集了样本，以捕获农业和城市的贡献，因为水从落基山脉的源头向东流动。这项研究的目的是评估低流量条件下农药对艾伯塔省南萨斯喀彻温河流域干线的点源贡献。除了检查源流类型和流域之间农药贡献的差异外，还分析了输入对主干河流的累积影响，土地利用的影响以及精选废水中农药的季节性。我们检测到17种农药和1种代谢产物，反映了农业和城市土地利用带来的径流。污水中农药的检出频率明显高于支流和干渠，夏季和冬季污水中的农药检出率较高。我们对土地利用关系的评估强调了农业对这些水生农业生态系统中农药发生的影响。据我们所知，