2021年5月24日
如果您去过当地的海滩，您可能已经注意到乱扔垃圾的风，例如空的薯片袋或塑料吸管。这些塑料经常进入海洋，不仅影响海洋生物和环境，还影响食品安全和人类健康。
最终，其中许多塑料分解为微观尺寸，使科学家难以量化和测量它们。研究人员称这些令人难以置信的小片段“纳米塑料" and "microplastics" because they are not visible to the naked eye. Now, in a multiorganizational effort led by the National Institute of Standards and Technology (NIST) and the European Commission's Joint Research Centre (JRC), researchers are turning to a lower part of the food chain to solve this problem.
The researchers have developed a novel method that uses a filter-feeding marine species to collect these tiny plastics from ocean water. The team published its findings as a proof-of-principle study in the scientific journal微塑料和纳米塑料。
塑料由通常由石油和其他化石燃料制成的合成材料组成。亚博网站下载每年生产超过3亿吨塑料，而800万吨最终进入了海洋。在海洋环境中发现的最常见的塑料类型是聚乙烯和聚丙烯。低密度聚乙烯通常用于塑料杂货袋或苏打罐的六包环中。聚丙烯通常用于可重复使用的食品容器或瓶盖。
“阳光以及其他化学和机械过程会导致这些塑料物体变得越来越小，”said NIST researcher Vince Hackley.“随着时间的流逝，他们改变了自己的形状，甚至改变了化学反应。”
尽管这些较小的纳米塑料没有官方定义，但研究人员通常将它们描述为人造产品，环境分解为微观碎片。它们通常相当于三分之一米的大小（一个千分尺或微米）或更小。
这些微小的塑料对环境和食物链构成了许多潜在的危害。"As plastic materials degrade and become smaller, they are consumed by fish or other marine organisms like mollusks. Through that path they end up in the food system, and then in us. That's the big concern,"哈克利说。
为了测量纳米塑料的帮助，研究人员转向了一组称为束缚的海洋物种，这些海洋物种通过其体内处理大量水以获取食物和氧气 - 并且无意间是纳米塑料。使束缚对该项目如此有用的是，他们可以在不影响塑料的形状或尺寸的情况下摄取纳米塑料。
对于他们的研究，研究人员选择了一种被称为C. robusta的调皮物种，因为“它们对微颗粒具有良好的保留效率，”yabo214said European Commission researcher Andrea Valsesia. The researchers obtained live specimens of the species as part of a collaboration with the Institute of Biochemistry and Cell Biology and the Stazione Zoologica Anton Dohrn research institute, both in Naples, Italy.
束缚物以纳米颗粒的形式暴露于不同浓度的聚苯乙烯，一种多功能塑料。yabo214然后收获束缚材料，然后进行化学消化过程，该过程将纳米塑料与生物体分离。然而，在此阶段，一些由皮膜消化的残留有机化合物仍与纳米塑料混合在一起，可能会干扰塑料的纯化和分析。
因此，研究人员使用了一种称为不对称流场流量分馏（AF4）的其他隔离技术，将纳米塑料与不需要的材料分开。然后可以收集分离或“分级”的纳米塑料以进行进一步分析。"That is one of the biggest issues in this field: the ability to find these nanoplastics and isolate and separate them from the environment they exist in,"瓦尔西亚说。
然后将纳米塑料样品放在专门设计的芯片上，以使纳米塑料形成簇，从而更容易检测并在样品中进行计数。最后，研究人员使用了一种基于非侵入性激光的技术拉曼光谱法来表征和识别纳米塑料的化学结构。
The special chips provide advantages over previous methods."Normally, using Raman spectroscopy for identifying nanoplastics is challenging, but with the engineered chips researchers can overcome this limitation, which is an important step for potential standardization of this method,"瓦尔西亚说。“该方法还可以以高灵敏度检测在剪裁酸酯中的纳米塑料，因为它将纳米颗粒集中在芯片上的特定位置。”yabo214
研究人员希望这种方法可以为未来的工作奠定基础。“我们正在做的几乎所有事情都在边境。没有广泛采用的方法或测量方法，”哈克利说。"This study on its own is not the end point. It's a model for how to do things going forward."
Among other possibilities, this approach might pave the way for using tunicates to serve as biological indicators of an ecosystem's health.“科学家可能能够在特定地点分析双线线，以查看该地区的纳米塑性污染，”said Jérémie Parot, who worked on this study while at NIST and is now at SINTEF Industry, a research institute in Norway.
The NIST and JRC researchers continue to work together through a collaboration agreement and hope it will provide additional foundations for this field, such as a reference material for nanoplastics. For now, the group's multistep methodology provides a model for other scientists and laboratories to build on.“这项合作的最重要的部分是有机会交流思想，以了解我们如何共同努力，”哈克利说。
来源：https://www.nist.gov/