Aim

was to assess whether a comprehensive approach linking existing knowledge with monitoring and modeling can provide an improved insight into coastal and marine plastics pollution. We focused on large micro- and mesoplastic (1–25 mm) and selected macroplastic items. Emission calculations, samplings in the Warnow river and estuary (water body and bottom sediments) and a flood accumulation zone monitoring served as basis for model simulations on transport and behavior in the entire Baltic Sea. Considered were the most important pathways, sewage overflow and stormwater. The coastline monitoring together with calculations allowed estimating plastics emissions for Rostock city and the Warnow catchment. Average concentrations at the Warnow river mouth were 0.016 particles/m³ and in the estuary 0.14 particles/m³ (300 µm net). The estuary and nearby Baltic Sea beaches were hot-spots for plastic accumulation with 6–31 particles/m². With increasing distance from the estuary, the concentrations dropped to 0.3 particles/m². This spatial pattern, the plastic pollution gradients and the observed annual accumulation values were consistent with the model results. Indicator items for sewer overflow and stormwater emissions exist, but were only found at low numbers in the environment. The considered visible plastics alone can hardly serve as indicator for microplastic pollution (<1 mm). The use of up-scaled emission data as input for Baltic Sea model simulations provided information on large scale emission, transport and deposition patterns of visible plastics. The results underline the importance of plastic retention in rivers and estuaries.

中文翻译：

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河口和波罗的海可见塑料的排放、运输和沉积——一种监测和建模方法

目的

是评估将现有知识与监测和建模联系起来的综合方法是否可以更好地了解沿海和海洋塑料污染。我们专注于大型微塑料和中塑料（1-25 毫米）以及选定的大塑料项目。排放计算、Warnow 河和河口（水体和底部沉积物）的采样以及洪水聚集区监测是整个波罗的海运输和行为模型模拟的基础。考虑的是最重要的途径，污水溢出和雨水。海岸线监测和计算可以估算罗斯托克市和沃诺流域的塑料排放量。Warnow 河口的平均浓度为 0.016 个颗粒/m³，河口为 0.14 个颗粒/m³（净值为 300 µm）。河口和附近的波罗的海海滩是塑料堆积的热点，每平方米有 6-31 个颗粒。随着与河口距离的增加，浓度下降到 0.3 个颗粒/平方米。这种空间格局、塑料污染梯度和观测到的年累积值与模型结果一致。存在下水道溢流和雨水排放的指标项目，但在环境中发现的数量很少。仅考虑的可见塑料很难作为微塑料污染（<1 mm）的指标。使用放大的排放数据作为波罗的海模型模拟的输入，提供了有关可见塑料的大规模排放、运输和沉积模式的信息。结果强调了塑料滞留在河流和河口的重要性。