Gathering information on plastic particles in composts and the processes they undergo is important in terms of potentially limiting their further entry into the environment, for example, in improving the fertilising properties of soils. Microplastics (MPs) were determined in composts produced from urban greenery. They are present in decreasing order: polyethylene terephthalate, polystyrene, polyethylene, and polypropylene. The determination of polymers and additives used to improve their properties was performed by pyrolysis and gas chromatography with mass spectrometric detection (Py-GC/MS). Additives and microplastics are most concentrated in composts in the 0.315˗0.63 and 0.63˗1.25 mm grain size class, together with the carbon contained in the compost dry matter. Additives form 0.11˗0.13% of MPs in dry matter of compost. The average concentration of microplastics in the particle size class from 0.63 to 1.25 mm is 2434 ± 224 mg/kg; in the total sample of composts, it is 1368 ± 286 mg/kg of P-MPs.

中文翻译：

---

城市堆肥中的塑料颗粒及其粒径分布

收集堆肥中塑料颗粒及其经历过程的信息对于限制其进一步进入环境（例如改善土壤的施肥性能）而言非常重要。在城市绿化产生的堆肥中测定了微塑料（MP）。它们按降序排列：聚对苯二甲酸乙二醇酯、聚苯乙烯、聚乙烯和聚丙烯。通过热解和气相色谱质谱检测 (Py-GC/MS) 来测定用于改善其性能的聚合物和添加剂。堆肥中的添加剂和微塑料最多集中在 0.315˗0.63 和 0.63˗1.25 毫米粒度级别，以及堆肥干物质中所含的碳。堆肥干物质中添加剂占 MP 的 0.11˗0.13%。粒径等级0.63至1.25毫米的微塑料平均浓度为2434±224毫克/千克；在堆肥总样品中，P-MP 含量为 1368 ± 286 mg/kg。