Distribution and transport of microplastic and fine particulate organic matter in urban streams
Distribution and transport of microplastic and fine particulate organic matter in urban streams
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城市溪流中微塑料和细颗粒有机物的分布和迁移
DOI：
10.1002/eap.2429
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发表时间：
2021
影响因子：
5
通讯作者：
Hoellein, Timothy J.
中科院分区：
文献类型：
--
作者：
Vincent, Anna E. S.;Hoellein, Timothy J.
塑料垃圾在世界各地的生态系统中堆积。河流是海洋塑料垃圾的主要来源。然而，河流也保留和转化塑料污染。虽然计算河流中颗粒传输动力学的方法已经很成熟，但很少被用来量化微塑料(即颗粒<；5 mm)在流动水中的传输和滞留。需要测量河流中的微塑料移动，以便更好地了解塑料垃圾在分水岭和全球范围内的命运，并为污染预防战略提供信息。我们的目标是(1)量化不同河流生境中微塑料的丰度，(2)采用有机物“螺旋式”指标来衡量微塑料与细颗粒有机物(FPOM)的同时传输。我们量化了城市河流生境(即地表水、水柱、底栖生物)中微塑料和FPOM的丰度，并计算了两种颗粒物的下游颗粒速度、滞留指数、周转率和螺旋长度。使用特定栖息地的方法对微塑料立木储量进行了评估，并扩大了估计范围，以涵盖研究范围。颗粒的空间分布表明，微塑料和FPOM被保持在一起，可能是通过促进颗粒下沉或再悬浮的流体动力。与FPOM相比，微塑料颗粒具有更高的下游颗粒速度和更低的保留指数，这表明在研究范围内，微塑料被保留的程度低于FPOM。微塑料也表现出较低的周转率和较长的螺旋长度，这归因于塑料降解速度较慢。因此，河流对微塑料的保持能力低于FPOM，尽管这两种颗粒保留在相似的位置。由于微塑料耐降解，单个颗粒在矿化之前可以比FPOM运输更长的距离，因此在这个过程中，微塑料颗粒可能会遇到更大的水体，并与各种水生生物群相互作用。这些对颗粒传输的经验评估将有助于理解淡水资源中微塑料颗粒的命运和转化，并最终有助于完善全球塑料预算。
Plastic litter is accumulating in ecosystems worldwide. Rivers are a major source of plastic litter to oceans. However, rivers also retain and transform plastic pollution. While methods for calculating particle transport dynamics in rivers are well established, they are infrequently used to quantify the transport and retention of microplastics (i.e., particles < 5 mm) in flowing waters. Measurements of microplastic movement in rivers are needed for a greater understanding of the fate of plastic litter at watershed and global scales, and to inform pollution prevention strategies. Our objectives were to (1) quantify the abundance of microplastics within different river habitats and (2) adapt organic matter “spiraling” metrics to measure microplastic transport concurrent with fine particulate organic matter (FPOM). We quantified microplastic and FPOM abundance across urban river habitats (i.e., surface water, water column, benthos), and calculated downstream particle velocity, index of retention, turnover rate, and spiraling length for both particle types. Microplastic standing stock was assessed using a habitat‐specific approach, and estimates were scaled up to encompass the study reach. Spatial distribution of particles demonstrated that microplastics and FPOM were retained together, likely by hydrodynamic forces that facilitate particle sinking or resuspension. Microplastic particles had a higher downstream particle velocity and lower index of retention relative to FPOM, suggesting that microplastics were retained to a lesser degree than FPOM in the study reaches. Microplastics also showed lower turnover rates and longer spiraling lengths relative to FPOM, attributed to the slow rates of plastic degradation. Thus, rivers are less retentive of microplastics than FPOM, although both particles are retained in similar locations. Because microplastics are resistant to degradation, individual particles can be transported longer distances prior to mineralization than FPOM, making it likely that microplastic particles will encounter larger bodies of water and interact with various aquatic biota in the process. These empirical assessments of particle transport will be valuable for understanding the fate and transformation of microplastic particles in freshwater resources and ultimately contribute to the refinement of global plastic budgets.