Most marine litter monitoring methods used on beaches focus on macro-litter (>25 mm) only and show shortcomings regarding smaller litter classes (<25 mm), especially at Baltic Sea beaches. Therefore, we used a sand rake method developed for large micro- (2–5 mm), and meso- (5–25 mm) litter to quantify the overall pollution status of Baltic Sea beaches and to test if the method is useful in terms of the requirements of the Marine Strategy Framework Directive (MSFD). Between July 2017 and October 2019, 197 sand rake method surveys were carried out at 35 regions around the Baltic Sea. In total, 9345 litter pieces were found on an area of 10,271 m2 of which 69.9% were 2–25 mm in size. Artificial polymers (4921 litter pieces) were predominant (mean 52.7% ± 13.3). Abundance of litter was 0.91 pieces/m2 ± 1.50 (median 0.40 pieces/m2). The most common litter were industrial pellets (19.8%), non-identifiable plastic pieces 2–25 mm (17.3%), cigarette butts (15.3%), and paraffin (11.9%). At 15 surveys at the German North Sea island of Sylt the litter abundance ranged from 0.45 pieces/m2 (median) to 0.59 pieces/m2 ± 0.37 (mean). Here, 69.2% of the litter was 2–25 mm in size and paraffin was predominant (69.2%). Beaches show a high pollution level with large micro- and meso-litter (2–25 mm) and our data can serve as a Baltic-wide pollution baseline. In contrast to the naked eye OSPAR method for macro-litter, the sand rake method is generally applicable on all sandy beaches, both urban and remote. This method also allows for the provision of a full spatial pollution pattern and can serve for assessing the effectiveness of marine litter mitigation measures.

中文翻译：

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波罗的海海滩的海洋垃圾污染——沙耙法的应用

海滩上使用的大多数海洋垃圾监测方法仅关注大型垃圾 (>25 毫米)，并且在较小的垃圾类别 (<25 毫米) 方面存在缺陷，尤其是在波罗的海海滩。因此，我们使用为大型微型（2-5 毫米）和中型（5-25 毫米）垃圾开发的沙耙方法来量化波罗的海海滩的整体污染状况，并测试该方法在以下方面是否有用海洋战略框架指令 (MSFD) 的要求。2017 年 7 月至 2019 年 10 月期间，在波罗的海周边 35 个地区进行了 197 次沙耙法调查。总共在 10,271 平方米的面积上发现了 9345 块垃圾，其中 69.9% 的大小为 2-25 毫米。人造聚合物（4921 窝）占主导地位（平均 52.7% ± 13.3）。垫料丰度为 0.91 件/平方米 ± 1.50（中值为 0.40 件/平方米）。最常见的垃圾是工业颗粒 (19.8%)、无法识别的 2-25 毫米塑料片 (17.3%)、烟头 (15.3%) 和石蜡 (11.9%)。在德国北海叙尔特岛的 15 次调查中，凋落物丰度范围从 0.45 件/平方米（中值）到 0.59 件/平方米 ± 0.37（平均值）。在这里，69.2% 的垫料大小为 2-25 毫米，石蜡占主导地位（69.2%）。海滩显示出高污染水平，有大量微型和中型垃圾（2-25 毫米），我们的数据可以作为波罗的海范围内的污染基线。与宏观垃圾的肉眼 OSPAR 方法相比，沙耙方法通常适用于所有沙滩，包括城市和偏远地区。这种方法还允许提供完整的空间污染模式，并可用于评估海洋垃圾缓解措施的有效性。