墨水河沉积物中微塑料的丰度、形态及其空间分布

Microplastics in Moshui River Sediment: Abundance, Morphology and Spatial Distribution

河流输入是海洋中微塑料的重要来源,然而目前关于河流沉积物中微塑料污染的资料十分有限。本文对我国山东省墨水河流域17个不同站位沉积物中微塑料的丰度、分布和形态等进行了研究。发现墨水河沉积物干样中微塑料的丰度为0kg-1~170kg^-1,低于同类型河流沉积物;人口密度大、工农业活动频繁及污水处理厂布设处微塑料丰度一般较大;同时,水动力条件对沉积物中微塑料的分布也有重要影响:支流汇入处丰度升高,水流湍急或水位高的站位丰度较小。本研究中最常见的粒径为>500μm,占71%;纤维状的微塑料占比最大(46.91%),其次是薄膜(40.74%)和颗粒状微塑料(12.35%)。微塑料的形态表明,墨水河沉积物中的微塑料多为次级来源。本研究表明,河流沉积物已经受到微塑料的污染,应该引起高度重视并采取适当措施。

Riverine input is one of the most important sources of microplastics in marine systems. Very limited information is currently available for pollution status and characteristics of microplastics in river sediments. In this work, the abundance, morphology and spatial distribution of microplastics in seventeen sediment samples of Moshui River of Shandong Province, China, were studied. Our results showed that the total abundance of microplastics varied between 0 and 170 particles·kg^-1, which is less than those reported for most rivers with similar hydrological conditions. The abundance of microplastics was usually higher at locations near areas heavily populated, heavily impacted by industrial and agricultural activities and closely adjacent sewage treatment plants. At the same time, the abundance was also significantly influenced by hydrodynamic conditions. It increased strongly in sediment samples collected near the confluence of tributaries, and decreased with water depth. The abundance also decreased drastically in sediment samples collected at places with turbulent waters. The size of microplastics that were most frequently detected in this work was less than 500 μm, accounting for 71% of the all microplastics. Fibers(46.91%) were the most common type of particles, which were followed by films(40.74%) and granules(12.35%). The morphological characterization of microplastic particles indicated that they were likely to be of a secondary origin, from degraded plastic debris that has been in the surrounding environment. Our study unveiled the emerging pollution of inland river sediments by microplastics. High awareness should be paid to and actions should be carried out to reduce the accumulation of microplastics in rivers.