ABSTRACT: Plastic pollution is present in aquatic systems worldwide. While numerous studies have investigated microplastic interactions with marine organisms, microplastic effects on freshwater organisms, especially insects, have been rarely studied. Previous studies have mainly focused on dietary uptake of microplastics, but the presence of microplastics in animal constructions is largely unknown. To date, microplastics have only been observed in the tubes of a marine polychaete species. In freshwater systems, common caddisfly (Trichoptera) larvae build cases by using larval silk and mineral grains from benthic sediments, which are known microplastic sinks. Therefore, we examined caddisfly cases for microplastic presence. We collected caddisfly Lepidostoma basale cases in the field, disintegrated them using hydrogen peroxide, and determined microplastic polymer type through micro-Fourier-transform infrared spectroscopy. We found primary and secondary microplastics of different shapes, colors, sizes and chemical compositions (e.g. polypropylene, polyethylene, polyvinyl chloride). Thus, this is the first study to show that microplastics are present in the biological construction of a freshwater organism. Larval stages are usually more vulnerable than adult individuals, and microplastics can transport persistent organic pollutants and emit toxic leachates. In the caddisfly larval case, those substances are in close proximity to the sensitive larval body, which may be harmful for the larva and may eventually impede its development. We discuss the potential of caddisfly larval cases to act as microplastic bioindicators in freshwater habitats.

中文翻译：

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将不同特性的微塑料掺入淡水鳞翅目鳞茎鳞茎幼虫的幼虫中

摘要：全世界的水生系统中都存在塑料污染。虽然许多研究已经研究了与海洋生物的微塑性相互作用，但很少研究对淡水生物（尤其是昆虫）的微塑性影响。先前的研究主要集中在饮食中摄取微塑料，但是在动物结构中微塑料的存在在很大程度上是未知的。迄今为止，仅在海洋多毛类物种的管中观察到微塑料。在淡水系统中，普通的鳞翅目（Trichoptera）幼虫通过利用幼虫丝和底栖沉积物中的矿物颗粒（称为微塑性水槽）来造壳。因此，我们检查了caddisfly病例中是否存在微塑性。我们收集了鳞翅目鳞翅目案例中，使用过氧化氢将其分解，并通过傅里叶变换红外光谱法确定微塑性聚合物类型。我们发现了形状，颜色，大小和化学成分（例如聚丙烯，聚乙烯，聚氯乙烯）不同的主要和次要微塑料。因此，这是第一个表明微塑料存在于淡水生物的生物构造中的研究。幼虫阶段通常比成年个体更脆弱，微塑料可以运输持久性有机污染物并释放有毒的渗滤液。在毒蝇幼虫的情况下，那些物质非常靠近敏感的幼虫体，这可能对幼虫有害，并最终阻碍其发育。