Abstract：
BACKGROUND: Most European rivers have not yet achieved \"good\" ecological status. In addition, the presence and abundance of microplastics (MPs) in freshwater is a matter of great concern to the scientific community.
METHODS: This study assesses the ecological status of four sampling sites of Selho (S1-S4) and Costa-Couros (C1-C4) rivers (Guimarães, Portugal), and the abundance of MPs in sediments and benthic macroinvertebrates (Oligochaeta) from those sites.
RESULTS: All sites of both rivers under higher pressure did not reach a \"good\" ecological status (S2-S3, C2-C4) based on the macroinvertebrate community. High levels of nutrients were observed at all sites in both rivers (except C2), especially phosphorus. In the Oligochaeta\'s gut of Costa-Couros river, the high number of MPs seems to be associated with their weight (95.25 ± 25.61 to 1069.00 ± 385.30 MPs g/fresh weight), suggesting the existence of malnutrition and digestive disorders, whereas the highest number of MPs in gut (134.00 ± 30.36 to 558.6 ± 100.70 MPs g/fresh weight) were found for the heaviest organisms of Selho.
CONCLUSIONS: Thus, sites with higher ecological status do not necessarily have lower abundance of MPs. In the sediments, urbanization seems to be the main driver for MP contamination. MP contamination is pervasive across the sediments and Oligochaeta\'s gut in both rivers. Since MPs have the potential to cause harm to environmental and human health, it is essential to monitor not only the ecological status of freshwaters, but also emerging pollutants such as MPs.
METHODS: This study assesses the ecological status of four sampling sites of Selho (S1-S4) and Costa-Couros (C1-C4) rivers (Guimarães, Portugal), and the abundance of MPs in sediments and benthic macroinvertebrates (Oligochaeta) from those sites.
RESULTS: All sites of both rivers under higher pressure did not reach a \"good\" ecological status (S2-S3, C2-C4) based on the macroinvertebrate community. High levels of nutrients were observed at all sites in both rivers (except C2), especially phosphorus. In the Oligochaeta\'s gut of Costa-Couros river, the high number of MPs seems to be associated with their weight (95.25 ± 25.61 to 1069.00 ± 385.30 MPs g/fresh weight), suggesting the existence of malnutrition and digestive disorders, whereas the highest number of MPs in gut (134.00 ± 30.36 to 558.6 ± 100.70 MPs g/fresh weight) were found for the heaviest organisms of Selho.
CONCLUSIONS: Thus, sites with higher ecological status do not necessarily have lower abundance of MPs. In the sediments, urbanization seems to be the main driver for MP contamination. MP contamination is pervasive across the sediments and Oligochaeta\'s gut in both rivers. Since MPs have the potential to cause harm to environmental and human health, it is essential to monitor not only the ecological status of freshwaters, but also emerging pollutants such as MPs.
摘要：
背景：大多数欧洲河流尚未达到“良好”的生态状况。此外,淡水中微塑料（MPs）的存在和丰富是科学界非常关注的问题。
方法：本研究评估了Selho（S1-S4）和Costa-Couros（C1-C4）河流（吉马良斯，葡萄牙),以及来自这些地点的沉积物和底栖大型无脊椎动物（Oligochaeta）中MP的丰度。
结果：根据大型无脊椎动物群落，两条河流在较高压力下的所有站点均未达到“良好”的生态状态（S2-S3，C2-C4）。在两条河流的所有地点都观察到高水平的营养物质(C2除外)，尤其是磷。在科斯塔-库罗斯河的Oligochaeta肠道中，MP的高数量似乎与他们的体重有关（95.25±25.61至1069.00±385.30MPg/鲜重），表明营养不良和消化系统疾病的存在，而在Selho最重的生物中，肠道中的MPs数量最高（134.00±30.36至558.6±100.70MPg/鲜重）。
结论：因此，具有较高生态状况的站点不一定具有较低的MPs丰度。在沉积物中，城市化似乎是MP污染的主要驱动因素。MP污染在两条河流的沉积物和Oligochaeta肠道中普遍存在。由于国会议员有可能对环境和人类健康造成伤害，不仅要监测淡水的生态状况，还有新兴的污染物，如国会议员。
方法：本研究评估了Selho（S1-S4）和Costa-Couros（C1-C4）河流（吉马良斯，葡萄牙),以及来自这些地点的沉积物和底栖大型无脊椎动物（Oligochaeta）中MP的丰度。
结果：根据大型无脊椎动物群落，两条河流在较高压力下的所有站点均未达到“良好”的生态状态（S2-S3，C2-C4）。在两条河流的所有地点都观察到高水平的营养物质(C2除外)，尤其是磷。在科斯塔-库罗斯河的Oligochaeta肠道中，MP的高数量似乎与他们的体重有关（95.25±25.61至1069.00±385.30MPg/鲜重），表明营养不良和消化系统疾病的存在，而在Selho最重的生物中，肠道中的MPs数量最高（134.00±30.36至558.6±100.70MPg/鲜重）。
结论：因此，具有较高生态状况的站点不一定具有较低的MPs丰度。在沉积物中，城市化似乎是MP污染的主要驱动因素。MP污染在两条河流的沉积物和Oligochaeta肠道中普遍存在。由于国会议员有可能对环境和人类健康造成伤害，不仅要监测淡水的生态状况，还有新兴的污染物，如国会议员。
