Département de Chimie, Université de Montréal, Montreal, Quebec, Canada.
Centre for Research on Watershed-Aquatic Ecosystem Interactions (RIVE), Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada.
Environ Pollut. 2019 Jul;250:29-39. doi: 10.1016/j.envpol.2019.03.125. Epub 2019 Apr 2.
The occurrence and spatial distribution of selected pesticides were investigated along a 200-km reach of the St. Lawrence River (SLR) and tributaries in Quebec, Canada. Surface water samples (n = 68) were collected in the summer 2017 and analyzed for glyphosate, atrazine (ATZ), 8 systemic insecticides (acetamiprid, clothianidin, dinotefuran, fipronil, imidacloprid, nitenpyram, thiacloprid, and thiamethoxam) and some metabolites. Overall, 99% of the surface water samples were positive to at least one of the targeted pesticides. The most recurrent compounds were glyphosate (detection frequency: 84%), ATZ (82%), thiamethoxam (59%), desethylatrazine (DEA: 47%), and clothianidin (46%). Glyphosate displayed variable levels (4-3,000 ng L), with higher concentrations in south tributaries (e.g., Nicolet and Yamaska). In positive samples, the sum of ATZ and DEA varied between 5 and 860 ng L, and the sum of 6 priority neonicotinoids between 1.5 and 115 ng L. From Repentigny to the Sorel Islands, the spatial distribution of pesticides within the St. Lawrence River was governed by the different upstream sources (i.e., Great Lakes vs. Ottawa River) due to the limited mixing of the different water masses. Cross-sectional patterns revealed higher concentrations of glyphosate and neonicotinoids in the north portions of transects, while the middle and south portions showed higher levels of atrazine. In Lake St. Pierre and further downstream, cross-sections revealed higher levels of the targeted pesticides near the southern portions of the SLR. This may be due to the higher contributions from south shore tributaries impacted by major agricultural areas, compared to north shore tributaries with forest land and less cropland use. Surface water samples were compliant with guidelines for the protection of aquatic life (chronic effects) for glyphosate and atrazine. However, 31% of the samples were found to surpass the guideline value of 8.3 ng L for the sum of six priority neonicotinoids.
研究沿着加拿大魁北克省圣劳伦斯河（SLR）及其支流 200 公里的河段选择的农药的发生和空间分布。2017 年夏季采集了地表水样本（n=68），并对草甘膦、莠去津（ATZ）、8 种系统杀虫剂（乙虫腈、噻虫啉、噻虫嗪、氟虫腈、吡虫啉、涕灭威、噻虫胺和噻虫砜）和一些代谢物进行了分析。总体而言，99%的地表水样本至少对一种目标农药呈阳性。最常见的化合物是草甘膦（检测频率：84%）、ATZ（82%）、噻虫胺（59%）、去乙基莠去津（DEA：47%）和噻虫啉（46%）。草甘膦显示出不同的浓度（4-3000ng/L），在南支流（如 Nicolet 和 Yamaska）的浓度较高。在阳性样本中，ATZ 和 DEA 的总和在 5 至 860ng/L 之间，6 种优先新烟碱类的总和在 1.5 至 115ng/L 之间。从 Repentigny 到 Sorel 群岛，圣劳伦斯河内部的农药空间分布受不同上游来源（即大湖与渥太华河）的影响，因为不同水体的混合有限。横截面模式显示，在横截面上，北部分段的草甘膦和新烟碱类浓度较高，而中南部的浓度较高。在圣皮埃尔湖及下游地区，横截面显示，在圣劳伦斯河南部附近的靶标农药浓度较高。这可能是由于与北岸支流相比，南岸支流受到受主要农业区影响的支流的贡献较高，北岸支流则有林地和较少的农田使用。地表水样本符合草甘膦和莠去津保护水生生物（慢性影响）的指导方针。然而，有 31%的样本被发现超过了优先 6 种新烟碱类总和 8.3ng/L 的指导值。
