Hajji Sara, Ben-Haddad Mohamed, Abelouah Mohamed Rida, Rangel-Buitrago Nelson, Ait Alla Aicha
Laboratory of Aquatic Systems, Marine and Continental Environments (AQUAMAR), Faculty of Sciences, Ibn Zohr University, Agadir 80000, Morocco.
Laboratory of Aquatic Systems, Marine and Continental Environments (AQUAMAR), Faculty of Sciences, Ibn Zohr University, Agadir 80000, Morocco.
Sci Total Environ. 2024 Oct 1;945:174115. doi: 10.1016/j.scitotenv.2024.174115. Epub 2024 Jun 20.
Wastewater treatment plants (WWTPs) are significant contributors to microplastic (MP) pollution in marine ecosystems when they are inefficient. This study aimed to evaluate the effectiveness of microplastic removal from the effluent of the Anza WWTP (Morocco), which processes industrial and urban wastewater using a lamellar decantation system combined with a submarine emissary for treated water discharge. Additionally, this study investigated the presence of microplastics in the Atlantic seawater where treatment plant effluent is released. Microplastics were collected and extracted from wastewater and seawater samples to assess their abundance, shape, size, polymer type, and removal rates in the treatment plant. The findings revealed an average MP concentration of 1114 ± 90 MPs/L in the influent and 607 ± 101 MPs/L in the effluent, indicating a removal efficiency of 46 %. Seasonal analysis revealed the highest MP concentrations during the summer, with 2181.33 MPs/L in the influent and 1209 MPs/L in the effluent. Seawater samples from the discharge zone of the submarine emissary had an average MP concentration of 1600 MPs/m. Characterization of the MPs revealed that fibers were the most common form of MPs in all the samples. The 500-100 μm size fraction was predominant in the WWTP samples, while MPs smaller than 1 mm were more abundant in the seawater samples. Seven polymer types were identified using attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR), with PET, PE, PVC, PA, PS, PP, and EVA being the most prevalent. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDX) revealed various degrees of weathering and chemical elements adhering to the MP surfaces. The results of this study provide valuable insights into the effectiveness of conventional treatment systems in removing microplastics and offer a reference for developing management strategies to mitigate MP pollution in Morocco's marine ecosystems.
污水处理厂（WWTPs）运行效率低下时，会成为海洋生态系统中微塑料（MP）污染的重要来源。本研究旨在评估摩洛哥安扎污水处理厂处理工业和城市废水的效果，该厂采用层流沉淀系统结合海底排放口排放处理后的水。此外，本研究调查了污水处理厂排放口所在的大西洋海水中微塑料的存在情况。从废水和海水样本中收集并提取微塑料，以评估其丰度、形状、大小、聚合物类型以及在处理厂中的去除率。研究结果显示，进水的微塑料平均浓度为1114±90个/升，出水为607±101个/升，去除效率为46%。季节性分析表明，夏季微塑料浓度最高，进水为2181.33个/升，出水为1209个/升。海底排放口排放区域的海水样本中微塑料平均浓度为1600个/立方米。对微塑料的表征显示，纤维是所有样本中最常见的微塑料形式。在污水处理厂样本中，500 - 100微米尺寸的微塑料占主导，而在海水样本中，小于1毫米的微塑料更为丰富。使用衰减全反射傅里叶变换红外光谱（ATR - FTIR）鉴定出七种聚合物类型，其中聚对苯二甲酸乙二酯（PET）、聚乙烯（PE）、聚氯乙烯（PVC）、聚酰胺（PA）、聚苯乙烯（PS）、聚丙烯（PP）和乙烯 - 醋酸乙烯酯共聚物（EVA）最为常见。扫描电子显微镜与能量色散X射线光谱（SEM/EDX）联用显示，微塑料表面存在不同程度的风化和附着的化学元素。本研究结果为传统处理系统去除微塑料的效果提供了有价值的见解，并为制定管理策略以减轻摩洛哥海洋生态系统中的微塑料污染提供了参考。
