Eighty surveys of ten Scottish beaches recorded litter sizes and weights. A simple model of fragmentation explains the distribution of plastic beach litter weights, producing a logarithmic cascade in weight-frequencies having a power law exponent of 1.6. Implications of fragmentation are numerous. Heavy litter is rare, light fragments are common. Monitoring by number is sensitive to minimum observable fragment size, age of the litter, and energy of the foreshore. Mean litter item weights should be used to calculate beach plastic loadings. Presence/absence of mega litter can distort monitoring by weight. Multiple surveys are needed to estimate mega litter statistics. Monitoring by weight can change the perception of the importance of litter sources (e.g., in our surveys, contribution from fishing was 6% by number, 41% by weight). In order to introduce consistency between beach surveys using visual methods by number, a standard minimum plastic fragment size should be introduced.

对十个苏格兰海滩的八十次调查记录了垃圾的大小和重量。一个简单的破碎模型解释了塑料海滩垃圾重量的分布，产生了幂律指数为 1.6 的重量频率的对数级联。碎片化的影响是多方面的。重的垃圾很少见，轻的碎片很常见。按数量监测对最小可观察碎片大小、凋落物年龄和前滨能量敏感。应使用平均垃圾物品重量来计算海滩塑料装载量。大量垃圾的存在/不存在会影响重量监测。需要多次调查来估计大量垃圾统计数据。按重量监测可以改变对垃圾来源重要性的看法（例如，在我们的调查中，捕捞的贡献为数量的 6%，重量的 41%）。