River plastic pollution is an environmental challenge of growing concern. However, there are still many unknowns related to the principal drivers of river plastic transport. Floating aquatic vegetation, such as water hyacinths, have been found to aggregate and carry large amounts of plastic debris in tropical river systems. Monitoring the entrapment of plastics in hyacinths is therefore crucial to answer the relevant scientific and societal questions. Long-term monitoring efforts are yet to be designed and implemented at large scale and various field measuring techniques can be applied. Here, we present a field guide on available methods that can be upscaled in space and time, to characterize macroplastic entrapment within floating vegetation. Five measurement techniques commonly used in plastic and vegetation monitoring were applied to the Saigon river, Vietnam. These included physical sampling, Unmanned Aerial Vehicle imagery, bridge imagery, visual counting, and satellite imagery. We compare these techniques based on their suitability to derive metrics of interest, their relevancy at different spatiotemporal scales and their benefits and drawbacks. This field guide can be used by practitioners and researchers to design future monitoring campaigns and to assess the suitability of each method to investigate specific aspects of macroplastic and floating vegetation interactions.

中文翻译：

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监测水葫芦中河流巨塑料截留的现场指南

河流塑料污染是日益受到关注的环境挑战。然而，关于河流塑料运输的主要驱动因素，仍有许多未知数。已发现漂浮的水生植物，如水葫芦，在热带河流系统中聚集并携带大量塑料碎片。因此，监测风信子中塑料的残留对于回答相关的科学和社会问题至关重要。长期监测工作尚未设计和大规模实施，可以应用各种现场测量技术。在这里，我们提供了一个关于可以在空间和时间上放大的可用方法的现场指南，以表征漂浮植被中的大塑料截留。塑料和植被监测中常用的五种测量技术被应用于越南的西贡河。其中包括物理采样、无人机图像、桥梁图像、视觉计数和卫星图像。我们根据这些技术导出感兴趣的指标的适用性、它们在不同时空尺度上的相关性以及它们的优点和缺点来比较这些技术。实践者和研究人员可以使用本实地指南来设计未来的监测活动，并评估每种方法在调查大塑料和漂浮植被相互作用的特定方面的适用性。我们根据这些技术导出感兴趣的指标的适用性、它们在不同时空尺度上的相关性以及它们的优点和缺点来比较这些技术。实践者和研究人员可以使用本实地指南来设计未来的监测活动，并评估每种方法在调查大塑料和漂浮植被相互作用的特定方面的适用性。我们根据这些技术导出感兴趣的指标的适用性、它们在不同时空尺度上的相关性以及它们的优点和缺点来比较这些技术。实践者和研究人员可以使用本实地指南来设计未来的监测活动，并评估每种方法在调查大塑料和漂浮植被相互作用的特定方面的适用性。