Hajji Sara, Ben-Haddad Mohamed, Abelouah Mohamed Rida, De-la-Torre Gabriel E, Alla Aicha Ait
Laboratory of Aquatic Systems: Marine and Continental Environments (AQUAMAR), Faculty of Sciences, Ibn Zohr University, Agadir, Morocco..
Universidad San Ignacio de Loyola, Av. La Fontana 501, Lima 12, Peru.
Sci Total Environ. 2023 Mar 1;862:160815. doi: 10.1016/j.scitotenv.2022.160815. Epub 2022 Dec 9.
Wastewater treatment plants (WWTPs) are some of the main sources of microplastics (MPs) in the environment. However, studies on the occurrence and removal efficiency of MPs in WWTPs are still scarce, especially in African countries. Thus, the aim of this work was to study the abundance of MPs in the influent and effluent of two WWTPs (Aourir and M'zar) from the Agadir metropolis (Moroccan Atlantic). The two WWTPs receive different wastewater inputs (domestic and industrial). In addition, the impacts of seasonality on the fate and removal efficiency were investigated. The results showed that the MPs abundance in the wastewater decreased from 188 MPs/L in the influent to 50 MPs/L in the effluent for Aourir WWTP (domestic inputs); while the abundance was greater in the M'zar WWTP (urban and industrial inputs) recording a mean value of 519 MPs/L and 86 MPs/L in the influent and effluent, respectively. MPs collected in the Aourir WWTP ranged from 290 to 3200 μm, while MPs from the M'zar WWTP, ranged from 330 to 4200 μm. Overall, the size range of 100-500 μm was the most abundant for both WWTPs. Fibers were the highest MPs morphotype found, followed by fragments. MP colors were mainly red, black, blue, and transparent for both treatment plants. Additionally, FTIR spectroscopy showed the presence of eight different polymers, mainly polyethylene (PE), polypropylene (PP), and polystyrene (PS). Seasonal variation analysis showed that MPs abundance in summer was significantly higher compared to other seasons. However, the comparison of the removal efficiency (RE) between the different seasons indicated that the winter season (74 %) recorded the highest RE for Aourir WWTP. Conversely, spring (87 %) recorded the highest RE for M'zar WWTP. SEM/EDX micrographs showed different degrees of weathering and chemical elements adhering to the surface of the MPs. The findings of the current study will serve as a baseline for future considerations about management strategies, wastewater reuse, as well as the understanding of the occurrence of microplastic pollution along the marine ecosystems of Morocco.
污水处理厂是环境中微塑料的主要来源之一。然而，关于污水处理厂中微塑料的存在情况和去除效率的研究仍然很少，尤其是在非洲国家。因此，本研究的目的是调查摩洛哥阿加迪尔市（摩洛哥大西洋沿岸）两座污水处理厂（奥里尔和姆扎尔）进水和出水中微塑料的丰度。这两座污水处理厂接收不同的废水输入（生活污水和工业污水）。此外，还研究了季节性对微塑料归宿和去除效率的影响。结果表明，奥里尔污水处理厂（生活污水输入）废水中微塑料的丰度从进水的188个/升降至出水的50个/升；而姆扎尔污水处理厂（城市污水和工业污水输入）的微塑料丰度更高，进水和出水的平均值分别为519个/升和86个/升。在奥里尔污水处理厂收集的微塑料尺寸范围为290至3200微米，而姆扎尔污水处理厂的微塑料尺寸范围为330至4200微米。总体而言，100 - 500微米的尺寸范围在两座污水处理厂中最为常见。纤维是发现的最主要的微塑料形态类型，其次是碎片。两座污水处理厂中微塑料的颜色主要为红色、黑色、蓝色和透明。此外，傅里叶变换红外光谱显示存在八种不同的聚合物，主要是聚乙烯（PE）、聚丙烯（PP）和聚苯乙烯（PS）。季节性变化分析表明，夏季微塑料的丰度明显高于其他季节。然而，不同季节去除效率（RE）的比较表明，冬季（74%）奥里尔污水处理厂的去除效率最高。相反，春季（87%）姆扎尔污水处理厂的去除效率最高。扫描电子显微镜/能谱分析（SEM/EDX）显微照片显示微塑料表面有不同程度的风化和附着的化学元素。本研究的结果将作为未来管理策略、废水回用以及了解摩洛哥海洋生态系统中微塑料污染情况的基线参考。
