转自：生态修复网
第一作者：凌茜、戴玉女；
通讯作者：邰义萍、张晓萌、杨扬；
责任通讯作者简介：杨扬 教授 热带亚热带水生态工程教育部工程研究中心 主任、国务院政府津贴专家，长期从事河流与人工湿地生态系统恢复过程与生态工程、水环境生态修复技术及理论研究。
资助基金：广州市水科学技术计划项目（440101-2021-00326；GZSWKJ2022-004）、广东省科技创新战略专项基金（2019A050505005）
原文链接：
https://doi.org/10.1080/15226514.2024.2442639
图文摘要 | Graphical abstract
植被化沟渠作为一种污染物修复技术，已被证实在净化水质方面具有显著效果。本研究针对美人蕉、再力花、香蒲和灯心草等水生植物在沟渠系统中对除草剂径流污染的削减潜力和机制进行了评估。研究发现，在模拟径流条件下，植被沟渠在去除阿特拉津和敌草隆方面显著优于无植被沟渠（p < 0.05）。美人蕉和香蒲在不同污染负荷下展现出最高的去除效率，分别达到43.02-72.61%和56.42-53.11%。植被沟渠中除草剂的半衰期由无植被沟渠的231.01-693.15小时显著缩短至99.02-230.05小时。此外，强降雨冲刷下植被沟渠中除草剂的释放率从无植被沟渠的48.95%显著降至34.10%（p < 0.05）。质量平衡分析证实生物降解是植被沟渠去除除草剂的主要途径（阿特拉津36.20%；敌草隆45.76%），其次为吸附作用（阿特拉津6.00%；敌草隆12.19%）。植物的存在显著促进了生物降解过程，敌草隆的降解效率提高了0.5倍，而阿特拉津的降解效率则提高了1倍。总之，植被沟渠在减少除草剂引起的径流污染方面具有重要作用，是城市水体管理和农业非点源污染控制有效的生态工程技术。
研究亮点 I Highlight
（1）探讨了农田重要除草剂阿特拉津和敌草隆在植被沟系统中的分布。
（2）土壤吸附是植物沟渠对农药重要的去除途径。
（3）植物促进了敌草隆和阿特拉津的生物降解。
（4）生物降解和吸附是降低植物沟渠除草剂再释放的主要过程。
工作的创新性 I Novelty of work
首次模拟强降雨冲刷条件下，综合评估美人蕉、再力花、香蒲和灯心草等水生植物对径流来源除草剂的去除和稳定效果，系统研究了这些植物对阿特拉津和敌草隆的生物累积潜力，并深入探讨了这两种除草剂在植被沟渠系统中的动态分布和迁移机制。结果证实，植被化沟渠作为一种实用的生态工程技术，有效减轻农业径流中除草剂污染负荷，为农业非点源污染控制提供了更为细致的数据支撑。
导读 | Introduction
全球各地在农业景观中使用了各种各样的农药，以减轻因昆虫、疾病和杂草导致的作物损失。值得注意的是，中国成为全球最大的农药消费国，2017年的年利用率为177万吨，这一数字比当时的全球平均水平高出5.84倍。农业中的大量农药使用会导致各种环境影响，广泛使用的除草剂阿特拉津和敌草隆显著污染了土壤、地表水和地下水。植物和土壤中的农药残留通过农业径流进入附近的水体，导致非点源污染并危害水生生物，这些农药在生物体内积累，并最终进入人类食物链，导致健康问题。将传统的农业排水沟改造成植被排水沟不会产生额外成本，是一种经济的方法来减轻农村非点源污染，阻止营养物和农药到达附近的地面水体，对于防止农业径流污染水生生态系统至关重要。。
有效缓解沟渠中的农药污染物依赖于水生植物、底物和微生物之间的相互作用。水生植物通过为微生物提供表面，增加细菌多样性来增强生物降解。本研究旨在测定模拟降雨径流过程中植被沟渠中阿特拉津和敌草隆的去除率，比较不同水生植物的截留效果，确定这些除草剂的去除途径。研究结果为生态沟渠中减少农药径流的植物选择提供了指导。
一、植被沟渠对污染物的去除效果
Pollutant removal effectiveness of vegetated ditches
植被沟渠与裸露沟渠相比，在低、高污染负荷条件下，两种除草剂的去除率均显著提高（p < 0.05），而植物种类之间没有显著差异（p > 0.05）（图1)。具体而言，低污染负荷条件下，无植被沟渠去除了18.36±1.98%阿特拉津和37.27±3.29%敌草隆；种植美人蕉沟渠去除两种除草剂效果最高，分别高达43.02±8.57%和72.61±5.02%，其他植被组去除分别低于40%和70%。高污染负荷条件下，相比裸露沟渠（阿特拉津去除率：27.03±4.10%、敌草隆去除率：48.94±4.44%），种植香蒲沟渠去除更多的阿特拉津（56.42%）和敌草隆（53.11%）。总体而言，植物沟渠均能有效地减少径流污染。
Vegetated ditches showed significantly higher removal rates of both herbicides compared to unvegetated ditches (p<0.05) across both low and high-doses, with no significant difference between plant species (p>0.05) (Figure 1). For low-dose treatments, unvegetated ditches removed 18.36±1.98% of atrazine and 37.27±3.29% of diuron. Among vegetated ditches, the C. indica group was most effective, removing 43.02±8.57% of atrazine and 72.61±5.02% of diuron, while other vegetated groups removed less than 40% of atrazine and 70% of diuron. For high-dose treatments, unvegetated ditches removed 27.03±4.10% of atrazine and 48.94±4.44% of diuron. T. latifolia ditches remove more herbicides (56.42% for atrazine, 53.11% for diuron) compared to other vegetated ditches. Overall, all four wetland plant ditches effectively reduce runoff pollution.
图1. 阿特拉津和敌草隆在所有沟渠系统中的总去除率。
不同的小写字母分别表示高、低污染负荷组中有、无植被沟渠去除率的显著差异（ p < 0.05）。
二、除草剂浓度和质量的下降过程
Decline process of herbicide concentrations and mass
图2显示了所有沟渠系统出水中除草剂的浓度随时间的变化。在第一阶段，阿特拉津和敌草隆的浓度最初在2小时因土壤快速吸附而降至最低点，然后逐渐增加并稳定。在低污染负荷组中，敌草隆浓度在2到5小时之间继续迅速下降。在第二阶段（5-48小时），低、高污染负荷组的阿特拉津质量分别下降10.37-38.41%和6.47-31.59%，而敌草隆质量分别下降19.18-39.59%和9.47-28.25%。有植被沟渠比无植被沟渠去除更多的敌草隆，表明植物在初始降雨后的长时间休息期间有助于除草剂的生物降解。在第三阶段（48-53小时），由于冲洗过程中的污染物释放和脱附，所有沟渠系统中的除草剂浓度急剧下降。低、高污染负荷条件下，阿特拉津的释放率分别可达41.16～59.45%和34.10～55.79%；敌草隆的释放率分别为23.73-39.80%和34.59-48.95%。在两种除草剂中，植被和非植被沟渠之间的释放率差异显著（ p < 0.05），但不同植物物种之间没有差异。在第四阶段（53-168小时），在不同系统中，敌草隆的质量减少了0.57-18.97%，其中美人蕉组减少幅度从8.43%到17.38%，截留效果最好。
Figure 2 shows the herbicides concentrations in the effluent of all ditch systems over time. In stage I, atrazine and diuron concentrations initially dropped to their lowest at 2h due to rapid soil adsorption, then gradually increased and stabilized. However, in the low-dose group, diuron concentrations continued to decline rapidly between 2 and 5h. During stage II (5–48h), the atrazine mass decreased by 10.37–38.41% in low-dose and 6.47–31.59% in high-dose treatments. The diuron mass decrease by 19.18–39.59% in low-dose treatments and 9.47–28.25% in high-dose treatments. Vegetated ditches removed more diuron than unvegetated ones, showing that plant aid in herbicide biodegradation during the long rest period after initial rainfall. During stage III (48–53h), herbicide concentrations dropped sharply in all ditch systems due to pollutant release and desorption during flushing. Atrazine release ranged from 41.16 to 59.45% in low-dose and 34.10–55.79% in high-dose treatments. Diuron release was 23.73–39.80% in low-dose and 34.59–48.95% in high-dose treatment. Significant differences in release rates were observed between vegetated and unvegetated ditches for both herbicides (p<0.05), but not between different plant species. During stage IV (53–168h), diuron mass decreased by 0.57–18.97% in various systems, with C. indica showing the highest retention, reducing ranged from 8.43 to 17.38%.
图2. 高、低污染负荷条件下沟渠系统中阿特拉津（A）和敌草隆（B）的浓度变化趋势。
三、植被沟渠系统土壤和植物对除草剂的积累
Accumulation of herbicides by soil and plants
径流冲刷试验后测定沟渠土壤与植被中残留除草剂的浓度，结果如图3所示， 低、高污染负荷条件下土壤中吸附的阿特拉津浓度分别为2.75-5.57 µg/kg和17.3-839.20 µg/kg，土壤中吸附的敌草隆浓度分别为6.30-13.78 µg/kg和24.97-45.98 µg/kg。无植被沟渠土壤吸附能力更强，植物沟渠之间也有显著不同（ p < 0.05）。不同植被均能积累这两种除草剂，积累规律表现为：高污染负荷条件积累更多，根部积累更多（3.93-25.88 µg/kg）；但宽叶香蒲在高、低污染负荷条件下地上部分积累除草剂均高于根部<0.5）。
Residual herbicide concentrations in ditch soil were measured post-experiment, as shown in Figure 3. Atrazine adsorption ranged from 2.75 to 5.57μg/kg at low doses and 7.3–839.20μg/kg at high doses. Diuron concentrations were 6.30–13.78μg/kg at low dose and 24.97–45.98μg/kg at high doses. Unvegetated control systems had significantly different herbicide adsorption compared to vegetated ditch systems (p<0.05). C. indica and T. dealbata showed significantly different soil adsorption of atrazine and diuron compared to J. effuses (p<0.05). At high doses, atrazine concentrations in the aboveground parts of C. indica, T. dealbata, T. latifolia, and J. effuses were 9.33, 1.95, 25.44, and 17.83μg/kg, respectively. Underground concentrations were 27.84, 14.90, 5.21, and 31.27μg/kg, respectively. Atrazine levels were significantly higher in the roots than in the aboveground parts of C. indica, T. dealbata, and J. effuses (p<0.5), except for T. latifolia.
图3. 沟渠土壤（A）和植物（B）组织中的除草剂浓度。
不同的字母表示高、低污染负荷组中有、无植被沟渠系统之间存在显著差异（ p < 0.05）。
四、除草剂在植被沟渠系统中的去除通路
Pathways of herbicides in ditch systems
污染质量平衡分析表明，阿特拉津和敌草隆在沟渠中的去除途径相似（图4)， 径流冲刷条件下植被沟渠中释放了34-46%的阿特拉津和23-40%的敌草隆，而无植被沟渠中分别释放了56-60%和40-49%，这也突显了植物在除草剂截留中的作用。生物降解是沟渠中除草剂的主要去除途径，阿特拉津和敌草隆的去除量贡献占比分别为14.93-48.49%和18.88-62.05%，其次是吸附作用，贡献率为2.75-18.39%，而植物吸收率最低，低于0.1%，植物沟渠提高了整体去除率，提升敌草隆和阿特拉津生物降解占比分别可达50%和100%。
Mass balance analysis showed similar removal pathways for atrazine and diuron in ditches (Figure 4). Runoff flush released 34–46% of atrazine and 23–40% of diuron in vegetated ditches, and 56–60% of atrazine and 40–49% of diuron in unvegetated ditches, highlighting the role of plants in herbicide interception. Biodegradation was the main removal pathway, accounting for herbicide removal (14.93–48.49% of atrazine and 18.88–62.05% of diuron. Sorption played a significant role in herbicide removal, contributing for 2.75–18.39%, while plant uptake was minimal at less than 0.1%. Despite low accumulation, plants indirectly boosted removal rates, enhancing diuron removal by about 50% and doubling atrazine removal through promoting biodegradation.
图4. 高、低污染负荷条件下沟渠系统中阿特拉津和敌草隆的去除途径分析。
总结 | Conclusions
植被沟渠系统能有效地降低降雨径流中除草剂的扩散风险，美人蕉和香蒲分别在降低低、高浓度阿特拉津方面更出色，并显著高于其他植物及无植物沟渠拦截效果。敌草隆具有更高的吸附亲和性比阿特拉津更容易被沟渠基质吸附，阿特拉津倾向于在宽叶香蒲地上部分积累更多，其他植物地上部分除草剂积累更多。质量平衡分析表明，生物降解和吸附是植被沟渠去除除草剂的主要作用；虽然植物没有显著积累污染物，但试验植物均有助于降解除草剂，根际效应显著促进了微生物降解，使敌草隆去除率提高50%，阿特拉津去除率提高了100%。这突显了根际相互作用在植物修复农业径流除草剂污染中的重要性。
Herbicides were effectively captured in vegetated ditch systems during agricultural. T. latifolia was more effective at reducing high atrazine levels, while C. indica excelled at lower concentrations. Both plants out performed other macrophytes in diuron reduction at all doses. Diuron, with a higher sorption affinity compared to atrazine, was more readily adsorbed by the substrate. Atrazine tended to accumulate more in the aerial parts of T. latifolia, whereas it mainly localized in the roots of other macrophytes. Mass balance analyses showed that biodegradation and adsorption were the main methods for herbicide reduction in vegetated ditches. Although plants did not significantly accumulate pollutants, macrophytes helped degrade the herbicide. The rhizosphere effect significantly boosted micro-biodegradation, increasing diuron removal by 50% and atrazine by 100%. This highlights the importance of plant-rhizosphere interactions in improving phytoremediation of herbicide-contaminated agricultural runoff.
文章来源：INT J PHYTOREMEDIAT
