Australian Rivers Institute, School of Environment and Science, Griffith University, Southport Qld, 4222, Australia.
Australian Rivers Institute, School of Environment and Science, Griffith University, Southport Qld, 4222, Australia.
Environ Pollut. 2022 Nov 15;313:120079. doi: 10.1016/j.envpol.2022.120079. Epub 2022 Sep 2.
Wastewater and stormwater are both considered as critical pathways contributing microplastics (MPs) to the aquatic environment. However, there is little information in the literature about the potential influence of constructed wetlands (CWs), a commonly used wastewater and stormwater treatment system. This study was conducted to investigate the abundance and distribution of MPs in water and sediment at five CWs with different influent sources, namely stormwater and wastewater. The MP abundance in the water samples ranged between 0.4 ± 0.3 and 3.8 ± 2.3 MP/L at the inlet and from 0.1 ± 0.0 to 1.3 ± 1.0 MP/L at the outlet. In the sediment, abundance of MPs was generally higher at the inlet, ranging from 736 ± 335 to 3480 ± 4330 MP/kg dry sediment and decreased to between 19.0 ± 16.4 and 1060 ± 326 MP/kg dry sediment at the outlet. Although no significant differences were observed in sediment cores at different depth across the five CWs, more MPs were recorded in silt compared to sandy sediment which indicated sediment grain size could be an environmental factor contributing to the distribution of MPs. Polyethylene terephthalate (PET) fibres were the dominant polymer type found in the water samples while polyethylene (PE) and polypropylene (PP) fragments were predominantly recorded in the sediment. While the size of MPs in water varied across the studied CWs, between 51% and 64% of MPs in the sediment were smaller than 300 μm, which raises concerns about the bioavailability of MPs to a wider range of wetland biota and their potential ecotoxicological effects. This study shows that CWs can not only retain MPs in the treated water, but also become sinks accumulating MPs over time.
污水和雨水都被认为是将微塑料（MPs）带入水生环境的重要途径。然而，关于湿地（CWs）作为一种常用的污水和雨水处理系统，可能对 MPs 产生的潜在影响，文献中几乎没有相关信息。本研究旨在调查不同进水源（雨水和污水）的五个 CWs 中水中和沉积物中 MPs 的丰度和分布。进水口水样中 MPs 的丰度范围为 0.4±0.3 至 3.8±2.3 MPs/L，出水口为 0.1±0.0 至 1.3±1.0 MPs/L。在沉积物中， MPs 的丰度通常在进水口较高，范围为 736±335 至 3480±4330 MPs/kg 干沉积物，在出水口降低至 19.0±16.4 至 1060±326 MPs/kg 干沉积物。尽管在五个 CWs 中不同深度的沉积物芯之间没有观察到显著差异，但在淤泥中记录到的 MPs 比在砂质沉积物中更多，这表明沉积物粒径可能是影响 MPs 分布的环境因素之一。在水样中发现的主要聚合物类型是聚对苯二甲酸乙二醇酯（PET）纤维，而在沉积物中主要记录到聚乙烯（PE）和聚丙烯（PP）碎片。虽然研究中的 CWs 中水中 MPs 的大小不同，但 51%至 64%的沉积物中的 MPs 小于 300μm，这引起了对 MPs 对更广泛的湿地生物群及其潜在生态毒理学影响的生物可利用性的关注。本研究表明，CWs 不仅可以在处理水中保留 MPs，还可以随着时间的推移成为积累 MPs 的汇。
