Boucher-Carrier Olivier, Brisson Jacques, Abas Khalil, Duy Sung Vo, Sauvé Sébastien, Kõiv-Vainik Margit
Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Sherbrooke East, QC, H1X 2B2 Montréal, Québec, Canada.
Département de Chimie, Université de Montréal, Complexe des sciences, 1375 Avenue Thérèse-Lavoie-Roux, H2V 0B3 Montréal, Québec, Canada.
Sci Total Environ. 2022 Sep 10;838(Pt 2):156061. doi: 10.1016/j.scitotenv.2022.156061. Epub 2022 May 20.
Glyphosate is the most widely used herbicide in the world, and consequently has polluted numerous water bodies through agricultural runoff. Treatment wetlands (TWs) have shown great promise for mitigating such pesticide contamination. The objectives of our study were to determine the effects of adding biochar to subsurface flow TW substrate, and to evaluate the performance of three North American macrophyte species (Phragmites australis subsp. americanus, Scirpus cyperinus and Sporobolus michauxianus) for removal of glyphosate. A synthetic agricultural runoff comprising 50 μg/L of glyphosate was applied to water-saturated TW mesocosms with mature vegetation during a 5.5-week period. Average removal efficiency, calculated on a mass balance basis, reached 78 and 82% for mesocosms with biochar (without and with plants, respectively), and 54 to 76% for those with macrophytes. Sporobolus michauxianus showed a lower evapotranspiration rate and less anoxic conditions in the lower part of the substrate, which resulted in lower overall removal performance. Aminomethylphosphonic acid (AMPA), the main toxic metabolite of glyphosate, was detected in all mesocosms, but at higher levels in planted ones. Results show that both the sorption capacity of biochar and the biodegradation processes associated with macrophytes contribute to glyphosate removal in TWs. Additionally, our results suggest that species selection is important to enhance favorable conditions and maximize removal of targeted pollutants.
草甘膦是世界上使用最广泛的除草剂，因此通过农业径流污染了众多水体。处理湿地（TWs）在减轻此类农药污染方面显示出巨大潜力。我们研究的目的是确定向潜流TW基质中添加生物炭的效果，并评估三种北美大型植物物种（美洲芦苇、毛果荸荠和米氏鼠尾粟）去除草甘膦的性能。在5.5周的时间内，将含有50μg/L草甘膦的合成农业径流施用于植被成熟的水饱和TW中型生态系统。基于质量平衡计算，添加生物炭的中型生态系统（分别为无植物和有植物的情况）的平均去除效率达到78%和82%，有大型植物的中型生态系统的去除效率为54%至76%。米氏鼠尾粟的蒸散速率较低，基质下部的缺氧条件较少，导致整体去除性能较低。在所有中型生态系统中均检测到草甘膦的主要有毒代谢产物氨甲基膦酸（AMPA），但在有植物的中型生态系统中含量较高。结果表明，生物炭的吸附能力和与大型植物相关的生物降解过程都有助于TWs中草甘膦的去除。此外，我们的结果表明，物种选择对于改善有利条件和最大限度地去除目标污染物很重要。
