Department of the Built Environment, Aalborg University, 9220 Aalborg Ø, Denmark.
Research Centre for Built Environment, Energy, Water and Climate, VIA University College, 8700 Horsens, Denmark.
Environ Sci Technol. 2023 Aug 22;57(33):12431-12441. doi: 10.1021/acs.est.3c03517. Epub 2023 Aug 10.
Shape matters for microplastics, but its definition, particularly for hyperspectral imaged microplastics, remains ambiguous and inexplicit, leading to incomparability across data. Hyperspectral imaging is a common approach for quantification, yet no unambiguous microplastic shape classification exists. We conducted an expert-based survey and proposed a set of clear and concise shapes (, , , , , , , , and ). The categories were validated on images of 11,042 microplastics from four environmental compartments (seven matrices: indoor air; wastewater influent, effluent, and sludge; marine water; stormwater; and stormwater pond sediments), by inviting five experts to score each shape. We found that the proposed shapes were well defined, representative, and distinguishable to the human eye, especially for and . , , and were though less distinguishable but dominated in all water and solid matrices. Indoor air held more , an abstract shape that appeared mostly for particles below 30 μm. This study highlights the need for assessing the recognizability of chosen shape categories prior to reporting data. Shapes with a clear and stringent definition would increase comparability and reproducibility across data and promote harmonization in microplastic research.
形状对微塑料很重要，但它的定义，特别是对于高光谱成像微塑料，仍然模糊不清，导致数据之间不可比。高光谱成像是一种常见的定量方法，但不存在明确的微塑料形状分类。我们进行了一项基于专家的调查，并提出了一组清晰简洁的形状（, , , , , , , , 和 ）。通过邀请五名专家对来自四个环境隔室（七种基质：室内空气；废水进水、出水和污泥；海水；雨水；和雨水池塘沉积物）的 11042 个微塑料图像进行评分，对这些类别进行了验证。我们发现，所提出的形状定义明确、有代表性且易于人眼区分，特别是对于 和 。 和 虽然不太容易区分，但在所有水和固体基质中都占主导地位。室内空气中含有更多的 ，这是一种主要出现在 30μm 以下颗粒上的抽象形状。本研究强调了在报告数据之前评估所选形状类别的可识别性的必要性。具有清晰严格定义的形状将增加数据之间的可比性和可重复性，并促进微塑料研究的协调一致。
