Microplastics are anthropogenic contaminants which have been found in oceans, lakes and rivers. Investigations focusing on drinking water are rare and studies have mainly been using micro-Fourier Transform Infrared Spectroscopy (μ-FT-IR). A major limitation of this technique is its inability to detect particles smaller than 20 μm. However, micro-Raman spectroscopy is capable of detecting even smaller particle sizes. Therefore, we show that this technique, which was used in this study, is particularly useful in detecting microplastics in drinking water where particle sizes are in the low micrometer range. In our study, we compared the results from drinking water distributed in plastic bottles, glass bottles and beverage cartons.

We tested the microplastic content of water from 22 different returnable and single-use plastic bottles, 3 beverage cartons and 9 glass bottles obtained from grocery stores in Germany. Small (–50-500 μm) and very small (1–50 μm) microplastic fragments were found in every type of water. Interestingly, almost 80% of all microplastic particles found had a particle size between 5 and 20 μm and were therefore not detectable by the analytical techniques used in previous studies. The average microplastics content was 118 ± 88 particles/l in returnable, but only 14 ± 14 particles/l in single-use plastic bottles. The microplastics content in the beverage cartons was only 11 ± 8 particles/l. Contrary to our assumptions we found high amounts of plastic particles in some of the glass bottled waters (range 0–253 particles/l, mean 50 ± 52 particles/l). A statistically significant difference from the blank value (14 ± 13) to the investigated packaging types could only be shown comparing to the returnable bottles (p < 0.05).

Most of the particles in water from returnable plastic bottles were identified as consisting of polyester (primary polyethylene terephthalate PET, 84%) and polypropylene (PP; 7%). This is not surprising since the bottles are made of PET and the caps are made of PP. In water from single-use plastic bottles only a few micro-PET-particles have been found. In the water from beverage cartons and also from glass bottles, microplastic particles other than PET were found, for example polyethylene or polyolefins. This can be explained by the fact that beverage cartons are coated with polyethylene foils and caps are treated with lubricants. Therefore, these findings indicate that the packaging itself may release microparticles. The main fraction of the microplastic particles identified are of very small size with dimensions less than 20 μm, which is not detectable with the μ-FT-IR technique used in previous studies.

微塑料是在海洋，湖泊和河流中发现的人为污染物。很少有针对饮用水的研究，并且研究主要是使用微傅立叶变换红外光谱（μ-FT-IR）。该技术的主要局限性在于它无法检测到小于20μm的颗粒。然而，显微拉曼光谱法能够检测甚至更小的粒径。因此，我们表明这项研究中使用的这项技术在检测粒径在低微米范围内的饮用水中的微塑料时特别有用。在我们的研究中，我们比较了在塑料瓶，玻璃瓶和饮料纸盒中分配的饮用水的结果。

我们测试了从德国杂货店获得的22个不同的可回收和一次性塑料瓶，3个饮料纸盒和9个玻璃瓶中水的微量塑料含量。在每种类型的水中都发现了小的（–50-500μm）和非常小的（1–50μm）微塑料碎片。有趣的是，发现的所有微塑料颗粒中，几乎80％的粒径在5到20μm之间，因此以前的研究中使用的分析技术无法检测到。可回收的平均微塑料含量为118±88颗粒/ l，而一次性塑料瓶的平均微塑料含量仅为14±14颗粒/ l。饮料纸盒中的微塑料含量仅为11±8颗粒/ l。与我们的假设相反，我们在一些玻璃瓶装水中发现了大量的塑料颗粒（范围为0–253颗粒/ l，平均为50±52颗粒/ l）。

可回收塑料瓶中水中的大多数颗粒被确定为由聚酯（主要为聚对苯二甲酸乙二醇酯PET，84％）和聚丙烯（PP； 7％）组成。这并不奇怪，因为瓶子由PET制成，瓶盖由PP制成。在一次性塑料瓶中的水中，仅发现了一些微型PET颗粒。在饮料纸盒以及玻璃瓶中的水中，发现了除PET以外的微塑料颗粒，例如聚乙烯或聚烯烃。这可以通过以下事实解释：饮料纸箱涂有聚乙烯箔，瓶盖用润滑剂处理。因此，这些发现表明包装本身可能释放出微粒。所识别的微塑料颗粒的主要部分尺寸非常小，尺寸小于20μm，