The contamination of freshwater ecosystems with microfibres has not yet been studied in Poland. We analysed samples from a river and three lakes located in central and northeastern Poland. A significantly higher number of fibres were reported in the river, which runs through large cities, compared with the lake situated within the Landscape Park. Fibres smaller than 1.0 mm dominated, especially in the river where they constituted 39% of all fibres detected. We found more microplastics (⩽ 4930 fibres·m⁻³) by using a mesh size of 20 µm compared with other studies of inland waters. The use of Raman spectroscopy allowed us to identify conventional plastic polymers: polyethylene terephthalate, polyester and polyurethane. We estimated that up to 25 g of microplastic in the form of fibres might be in the lake water under the surface. We found microplastic fibres in Majcz Lake situated within the Masurian Landscape Park. This suggests that microfibres are carried by the wind and rain and enter freshwater isolated from sewage outlets. By using the control sample and an air-test of microfibres in the laboratory, we observed that there is a high probability of contamination with microplastic in the field samples (up to 30% of all fibres detected). The contamination risk noted from the samples cannot be ignored; this could be particularly important for analysis of microplastic in remote freshwater ecosystems.

波兰尚未研究微纤维对淡水生态系统的污染。我们分析了位于波兰中部和东北部的一条河流和三个湖泊的样本。据报道，与风景公园内的湖泊相比，穿过大城市的河流中的纤维数量明显增加。小于1.0毫米的纤维占主导地位，尤其是在河流中，占所有检测到的纤维的39％。我们发现了更多的微塑料（⩽4930纤维·m ^-3），与其他内陆水域研究相比，使用的网目尺寸为20 µm。拉曼光谱的使用使我们能够识别常规的塑料聚合物：聚对苯二甲酸乙二酯，聚酯和聚氨酯。我们估计在表面下的湖水中可能有多达25 g呈纤维形式的微塑料。我们在Masurian景观公园内的Majcz湖中发现了微塑性纤维。这表明微纤维被风和雨携带并进入与污水出口隔离的淡水。通过在实验室中使用对照样品和对超细纤维进行空气测试，我们观察到现场样品中极有可能被微塑料污染（检测到的所有纤维中多达30％）。从样品中注意到的污染风险不容忽视；