We describe a simple single-pot method for collection and preparation of natural water for microplastic analyses. The method prepares samples in the same vessel (mason jars) that they are collected in right up until the microplastics are transferred onto filters or spectroscopic windows for analyses. The method minimized contamination, degradation, and losses, while increasing recoveries and throughput when compared with conventional sieving. We applied it to surface grab samples collected from the Mississippi River and its major tributaries during and after historic flooding in 2019. Microplastics (>~30 µm) were quantified using Nile red fluorescence detection, and a small subset of samples were identified by micro-Fourier transform infrared imaging spectroscopy. Concentrations were lower during the flooding, likely due to dilution. Concentrations ranged from approximately 14 microplastics/L in the Tennessee River during flooding to approximately 83 microplastics/L in the Ohio River during low-flow (summer) conditions. Loads of microplastics tended to increase downriver and ranged from approximately 87 to approximately 129 trillion microplastics/d near New Orleans. Most of the microplastics (>60%) were in the lower size fraction (~30-90 µm) and consisted primarily of fragments (~85%), followed by fibers (~8%) and beads (~7%), with polyester, polyethylene, polypropylene, and polyacrylate as the primary microplastic types. Overall, we demonstrate that the single-pot method is effective and versatile and, because it uses relatively inexpensive and easily assembled materials, can be adapted for microplastic surveys worldwide, especially those involving sample collection by volunteers from the community and schools. Environ Toxicol Chem 2020;39:986-995. © 2020 SETAC.

中文翻译：

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用于微分析的天然水收集和制备的单罐方法：历史洪水期间和之后，密西西比河系统中的微塑料。

我们描述了一种用于收集和制备用于微塑性分析的天然水的简单单锅法。该方法将样品收集在同一容器（玻璃瓶）中，直到将其直接收集到微塑料被转移到过滤器或光谱窗口上进行分析为止。与常规筛分相比，该方法将污染，降解和损失降至最低，同时提高了回收率和产量。我们将其应用于2019年发生历史性洪灾期间和之后从密西西比河及其主要支流收集的地表样品。使用尼罗红荧光检测对微塑料（>〜30 µm）进行定量，并通过微分离来鉴定一小部分样品。傅立叶变换红外成像光谱。洪水期间的浓度较低，可能是由于稀释所致。浓度范围从洪水期间田纳西河的约14微塑料/ L到低流量（夏季）条件下的俄亥俄河的约83微塑料/ L。微塑料的负荷趋于增加，在新奥尔良附近，微塑料的负荷从每天约87到约129万亿微天/天。大多数微塑料（> 60％）的尺寸分数较低（〜30-90 µm），主要由碎片（〜85％）组成，其次是纤维（〜8％）和珠子（〜7％），聚酯，聚乙烯，聚丙烯和聚丙烯酸酯是主要的微塑料类型。总体而言，我们证明了单罐法是有效且通用的，并且由于它使用的是相对便宜且易于组装的材料，因此可以适用于全世界的微塑性调查，特别是那些涉及社区和学校志愿者收集样品的活动。Environ Toxicol Chem 2020； 39：986-995。©2020 SETAC。